United States Air and Radiation EPA420-R-00-013
Environmental Protection August 2000
Agency
vxEPA Evaluation of On Board
Diagnostics for
Use In Detecting
Malfunctioning and
High Emitting Vehicles
> Printed on Recycled Paper
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EPA420-R-00-013
August 2000
of On for
In
Edward Gardetto and Ted Trimble
Transportation and Regional Programs Division
Office of Transportation and Air Quality
U.S. Environmental Protection Agency
NOTICE
This technical report does not necessarily represent final EPA decisions or positions.
It is intended to present technical analysis of issues using data that are currently available.
The purpose in the release of such reports is to facilitate the exchange of
technical information and to inform the public of technical developments which
may form the basis for a final EPA decision, position, or regulatory action.
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Executive Summary:
In this report we describe a test program designed to give preliminary answers to the questions:
* Is there a benefit of identifying the emissions problems of vehicles with the OBD
system and how does it compare to the available tailpipe tests?
* Will OBD pass any vehicles which are emitting at levels that are of concern in I/M?
A total of 201 vehicles qualified for this program, 194 with the MIL illuminated and 7 high
emitters with no MIL illumination. After testing these vehicles we concluded that:
* OBD technology is a viable I/M test for 1996 and newer vehicles. The emission
reductions available from basing repairs on OBD appear to be at least as large and possibly larger
than emission reductions obtained from I/M tailpipe tests.
* OBD did miss some high emitters but performed better than available I/M tailpipe tests.
* Some areas of OBD technology still need to be refined and the vehicles with OBD
technology should be monitored for the effect of aging.
* OBD I/M offers preventative maintenance which allows benefits previously unavailable
to I/M programs to be claimed.
Background:
On August 6, 1996, under the authority of the Clean Air Act (CAA) as amended in 1990,
the EPA published rules requiring the use of On-Board Diagnostics (OBD) in inspection and
maintenance (I/M) programs (40 CFR parts 51 and 85). This provision required I/M programs to
incorporate an OBD check of OBD equipped vehicles in addition to traditional tailpipe testing on
January 1, 1998. The Agency decided to delay the mandatory startup of OBD I/M until January 1,
2001 for a variety of reasons. The primary reason was that there was little data on the
performance of OBD systems in-use, given the relative newness of OBD technology. An
additional concern existed over the level of understanding of the technology in the states and
repair industry. During the delay period the Agency conducted a test program to evaluate the
usefulness of OBD for I/M and to determine the associated emission benefits. This effort was
coordinated with stakeholders through the Mobile Sources Technical Review Subcommittee, a
workgroup formed by the Clean Air Act Advisory Committee (CAAAC). The CAAAC was
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formed under the 1972 Federal Advisory Committee Act (FACA) in order to advise the Agency
on technical matters.
Under the original OBD I/M requirement (Aug. 6, 1996), the Agency intended to collect
test data from all I/M programs using both the EVI240 tailpipe test and OBD. Using the data
collected, the Agency would determine the effectiveness of the OBD test in comparison to the
EVI240 test and develop emission reduction credits associated with the OBD test. Subsequent to
the 1996 regulation, the I/M test environment changed significantly and the use of the EVI240 test
was not as prevalent as expected. Additional information came to light in the same time frame
which indicated that the EVI240 test as originally designed has what is known as a
"preconditioning" issue1. Technical discussions about the appropriateness of comparing OBD to a
"hot" start test (EVI240) and not the Federal Test Procedure (FTP), which is a "cold" start test,
were raised both internally at EPA and within the FACA. The cumulative impact of these
concerns in I/M was that the comparison of OBD to I/M tailpipe testing, as conducted in the
inspection lanes, became of questionable value. The test program described here was undertaken
by EPA in order to alleviate the need for states to run dual tests (tailpipe and OBD) in their I/M
lanes as a form of data gathering2. This report is the result of that test program.
Test Study Design:
It was decided (based on advice from the FACA) to conduct an FTP based test program with a
minimum of 200 vehicles3. Vehicle numbers were limited by economics (FTP tests cost several
thousand dollars per test per vehicle) and the understanding that the goal of this test program was
to provide a first look at the use of OBD compared to tailpipe I/M testing. It is generally accepted
that the EVI240 is the most accurate I/M test4, so we decided that the EVI240 would be considered
a best case scenario.
In developing the test program several questions had to be considered. First, what is the benefit of
using OBD systems to identify emissions exceedences and how does it compare to available
tailpipe tests in identifying emissions problems? For this question, vehicles with the malfunction
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indicator light (MIL) illuminated would be recruited for the test program. All the post-repair
emissions evaluations would have to be based solely on the diagnosis provided by the OBD
system as this is accepted industry repair practice for post 1996 model year vehicles.
Second, does OBD miss any vehicles which are emitting at levels that are of concern in I/M (i.e.
high tailpipe emissions with no MIL)? For this question, vehicles with potentially high emissions
that were not detected by the OBD system would have to be identified.
Because of concerns about the relatively small sample size and the ease of procurement of
domestic vehicles it was decided that the sample should be weighted based on manufacturer
production for the largest 6 producers. The remaining manufacturers represent a small percentage
(< 10%) of the entire fleet. "Other" was used to represent the remaining manufacturers. There
was also concern that light-duty trucks (LDT) would not be adequately represented unless the
sample was weighted for their inclusion. Table 1 below was developed for a 200 vehicle sample
based on 1997 sales5.
Table 1: Procurement Goals Based on Production
MFR
LDV
LDT
Total
GM
35
27
62
Ford
21
29
50
Daimler-
Chrysler
10
20
30
Toyota
11
5
16
Honda
11
1
12
Nissan
7
3
10
Other
10
10
20
Total
105
95
200
Once identified, vehicles would receive the EVI240 and FTP emissions tests and an OBD system
check prior to any maintenance being performed. This would provide the "As-Received"
emissions profile of the vehicle. The FTP would be considered the standard for comparing any
emissions reductions and the EVI240 and OBD checks would only provide information on
identifying vehicles into categories (pass/fail). For vehicles that needed repairs (based on OBD or
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tailpipe results), a second series of tests would be run to provide information on the emission
changes as a result of the repairs.
Methods:
During a two year period (9/97- 10/99) sampling was conducted at 4 labs [National Vehicles and
Fuels Emissions Laboratory (NVFEL) in Ann Arbor, Michigan; Automotive Testing Laboratory
(ATL) in Mesa, Arizona; Colorado Department of Health Laboratory (CDH) in Aurora, Colorado;
and California Air Resources Board (CARB) in El Monte, California].
For vehicles with the MIL illuminated, any vehicle with a non-evaporative emissions related
trouble code (evaporative emissions will be discussed in a separate report) commanding the MIL
on was accepted into the program6. These vehicles were selected without knowledge of the
tailpipe emissions. Vehicles with misfire codes are relatively common, therefore, an upper limit
of 25% of any manufacturer's sample was established, based on a fleet survey of 100,000
vehicles in Wisconsin and the relative occurrence of misfire diagnostic trouble codes (DTC)s in
the I/M lane7. Locating vehicles with MILs illuminated was difficult. Vehicles were solicited
through newspaper ads, notices in the E-Mail of large organizations etc., but in the end,
recruitment relied heavily on rental fleets, repair facilities, and used car dealers. These businesses
provided a more concentrated source of new vehicles to select from and monitor for MIL
illumination.
FTP testing was performed using methods described in CFR 86.130-96 with the exception that no
diurnal heat build was performed and no SHED testing was conducted. EVI240 testing was done
in accordance with EPA Technical Guidance EPA-AA RSPD EVI 98-1. OBD information was
gathered using SAE compliant (SAE 1978) scan tools from various manufacturers. Maintenance
on vehicles was performed at either the original manufacturer's dealership or by mechanics
following the manufacturer's available service information.
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Vehicles procured with the MIL illuminated were inspected for safety and OBD information then
tested using the LAB240 (see definition in appendix 5) procedure with the fuel that was in the
tank (fuel samples were taken and analyzed for sulfur content). The vehicles were then drained of
in-use fuel and refueled with indolene test fuel. Next the vehicles received a standard FTP and a
second LAB240. These FTP emissions represent the "before" level of emissions. The vehicles
were then sent for repairs, if called for by either the OBD status or the FTP emissions levels.
After repair it was again tested on the FTP to determine the "after" level of emissions. Any
difference measured between the two FTPs represented the air quality improvement attributable to
the repair. (See appendix 2 for test sequence details)
Maintenance performed in this program followed OEM published procedures and (in some cases
consultation with OEM engineers augmented published information when high tailpipe emissions
with no OBD problem existed). In cases where a scan of the OBD system indicated a diagnostic
trouble code, but the technicians could find nothing wrong, the OBD system was reset. The OBD
system was then allowed to verify the absence of any OBD problem.
Two vehicles came in with emissions extremely high and/or running so poorly that they could not
be FTP tested. These were repaired and their costs were included in the cost data but since we had
no initial test we could not ascertain an air quality benefit. See discussion in appendix 6, Table x2.
Procurement of High emitting vehicles with no MIL illumination
To recruit vehicles with high emissions and no MIL illumination we used LANE240 (see
definition in appendix 5) test data. Additionally some attempts were made at identifying vehicles
which experience indicated could have high emissions (e.g. high mileage, driveability problems).
The most stringent EVI240 standards8 were applied even though the actual state I/M program did
not fail vehicles based on these values. For testing conducted at the ATL facility an agreement
was made with the contractor for one of the local EVI240 lanes to test 1996 and newer vehicles
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using the full test (no fast pass) and applying the appropriate cut points. When a vehicle was
identified, ATL personnel were notified and the owner was approached regarding the use of the
vehicle in the test program. ATL also put pamphlets in all of the other Phoenix I/M lanes
requesting owners to contact them if they failed the LANE240 test. At the CDH lab, LANE
EVI240 failing vehicles were identified using the state's computer data base. Owners were
contacted via phone or mail to request the use of the vehicle in the test program. For vehicles
recruited using LANE EVI240, if the vehicle passed the LAB EVI240 they were released because
they were an error of commission by the LANE EVI240. Because the NVFEL lab is not located
near an operating I/M program no attempts were made using I/M as a screening tool. NVFEL,
along with ATL and CDH did attempt to find vehicles which OBD may have missed by recruiting
vehicles that were suspected of having high emissions even without any quantitative verification.
These vehicles tended to be ones that local mechanics said were running poorly, or vehicles with
very high mileage. On the vehicles which were suspected high emitters without any tailpipe data,
the LAB EVI240 was also used as a screening tool.
Results:
Sample
201 vehicle tests were conducted in the program, versus a target of 200 vehicles (1 vehicle
procured twice). Table 2 represents the breakdown of this sample by manufacturer and vehicle
type, cars (LDV) and trucks (LDT).
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Table2: Description of Sample by Manufacturer and Type
MFR
LDV
LOT
Total
GM
#procured
(% of goal)
45
(128%)
18
(66%)
63
(102%)
Ford
31
(148%)
28
(96%)
59
(116%)
Diamler-
Chrysler
22
(220%)
16
(80%)
38
(127%)
Toyota
5
(45%)
1
(20%)
6
(38%)
Honda
8
(73%)
0
(0%)
8
(67%)
Nissan
7
(100%)
4
(133%)
11
(110%)
Other
14
(140%)
2
(20%)
16
(80%)
Total
132
(126%)
69
(73%)
201
(100%)
The category of "other" is made up of the following LDVs and LDTs in the sample:
Mazda n= 2
VW n=3
Isuzu n=2(LDT)
Hyundai n= 3
Kia n= 1
Saab n= 1
Volvo n= 1
Suzuki n= 3
Breakout by model year
LDV
LOT
1996
28
27
1997
33
22
1998
38
14
1999 2000
32 1
6 0
Odometer readings
MINIMUM
AVERAGE
MAXIMUM
LDV
29
26440
93575
LOT
3981
54505
245000
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Of the 201 vehicles in the sample, 194 were procured with the MIL illuminated. Table 3 shows
how these vehicles compared to the FTP tailpipe test.
Table 3: Vehicles with MIL illuminated
LDV
LOT
Total
# with MIL illuminated
(# that MIL went out*)
128 (subset of 5)
66 (sub set of 6)
194 (subset ofll)
# which failed FTP over
appropriate cert, standard
40
18
58
subset that failed over 1.5
times standard
21
10
31
* denotes that MIL self-extinguished while vehicle was undergoing FTP testing
Table 3 includes two vehicles which are assumed to have failed their as-received FTP at over 1.5
times the applicable tailpipe standards9. These vehicles could not be driven on the FTP trace and
therefore no tailpipe readings are available. A description of these vehicles is in appendix 6.
Part of the recruitment process was to find vehicles with high emissions and no MIL illumination.
EVI lanes or technicians identified eight (8) vehicles which ultimately qualified as having high
emissions with no MIL illumination. These vehicles represent vehicles which failed a LAB240
without MIL illumination. Table 4 represents a summary of these data
Table 4: Sample of Vehicles with no MIL Illumination
LDV
LOT
Total
# with no
MIL
4
4*
8
# which failed FTP over cert.
standard (includes over 1.5X)
2
3*
5
# which failed FTP over 1.5
times standard
1
3*
4
*CDH04 was recruited for no MIL but subsequent scanning of the OBD systems showed that the MIL was commanded on. This truck is not
considered an OBD miss.
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The ability of OBD to correctly identify vehicles which are emitting at levels significantly over
their applicable certification standard (2x) was also investigated. The subgroup of vehicles
making up this sample is listed in Table 5.
Table 5: Vehicles over twice their certification standard
LDV
LOT
# over twice
cert standard
15
6
# with MIL on
(w/FTP over 2X)
14
5
# which failed LABIM240
(w/FTP over 2X)
7
6
The one LDV (CDH03) and one LOT (CDH33) which were missed by OBD were failed by the
LAB EVI240; the eight LDVs which were missed by the LAB EVI240 were failed by the OBD
scan.
Information on the ability to repair high emitting vehicles based solely on extinguishing the MIL
was also collected. Of the 15 LDVs with emissions over twice their standard 12 (80%) retested,
after repairing for the MIL illumination, to below the certification standard. For LDTs the number
was 4 (80%) of 5 over twice certification standards. All the LDVs tested below 1.5X the
applicable standards after repair. The vehicles remaining above their standard after repair but with
no MIL are discussed in another section of this report (Table 10).
Repairs conducted in this test program provide information on the cost of repairing for MIL
illuminations (Table 6). Many of the vehicles in this program were still within their warranty
period and cost details were not given on the repair invoice. Costs for repairs were assigned to
them based on parts costs and a labor rate of $70 per hour. Vehicles with "maintenance not
required" (MNR) were charged 1 hour of labor. See appendix 3 for details on how costs were
assigned.
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Table 6: Average Cost of OBD Repair
LDV
LOT
Total
# repaired
for MIL
128
66
194
# with
MNR
25
14
39*
Average cost of repair
(includes 1 hr cost for
MNR)
$252
$284
Average cost of repair
excluding MNR
$287
$322
* 29 of the 39 had misfire or fuel trim OBD codes which we believe would be repaired in the field but were not
repaired for this program.
The cost of repairs varied greatly in the sample. The most costly repair was $2,150 for repair of
two cylinder heads on a LDV (CDH 32). The most costly LOT (ATL 090) repair was $1,974 for
replacement of a transmission (OBD transmission fault detected (see discussion in appendix 7).
The median repair cost for LDV was $160 while for LDT the median was $210. Based on
current waiver regulations (~$600 waiver limit10), at least 94% of the LDV and 91% of the LDT
could be repaired for below current I/M waiver limits.
Emissions reductions attributable to OBD repairs (and LAB IM240) are in Table 7. The IM240
repair data overlap with the OBD repair information in this table based on each test's ability to
identify a vehicle. It should be noted that CDH did not measure non-methane hydrocarbon
(NMHC) and CARB did not measure total hydrocarbon(THC) for their respective vehicles. The
THC and NMHC averages in the tables reflect averages calculated from vehicles with only these
measured emissions. LDV and LDT data are presented separately because we think that there is a
significant difference in the stringency of the control strategies. The reader may combine these
data without hazard as they were all gathered and combined in the same fashion.
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Table 7: Average Reductions from Repairs
LDV
average
reduction for
OBD repair
N=126
average
reductions for
OBD repairs
with $600
repair limit
n=118
average
reduction for
EVI240 repair
n=7
THC
.138 gpm
n=114
0.1 gpm
n=108
1.04 gpm
n=7
NMHC
0.1 gpm
n= 111
0.1 gpm
n= 105
0.9 gpm
n=5
CO
2.40 gpm
n=126
2.42 gpm
n=118
15.4 gpm
n=7
NOx
0.1 gpm
n=126
0.1 gpm
n=118
0.6 gpm
n=7
CO2
6.47
gpm
n=114
6.21
gpm
n=108
14.71
gpm
n=7
MPG
-0.53 mpg
(increase in
fuel economy)
n=114
-0.53 mpg
n=108
-2.36 mpg
n=7
Vehicle ATL78 was not included in the calculations of for either OBD or EVI240 since no FTP
results were available. Vehicle ATL96 was excluded from the calculations for OBD (EVI240 did
not identify this vehicle) for the same reason.
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Table 7 continued
LOT
average reduction
for OBD repair
n=65
average
reductions for
OBD repair with
$600 limit n=60
average reduction
for EVI240 repair
n=7
THC
.11 gpm
n=65
0.10 gpm
n=60
0.84 gpm
n=7
NMHC
0.05 gpm
n=49
0.05 gpm
n=46
0.37 gpm
n=5
CO
1.56 gpm
n=65
1.62 gpm
n=60
10. 47 gpm
n=7
NOx
0.13 gpm
n=65
0.08 gpm
n=60
0.60 gpm
n=7
CO2
-2.66gpm
n=64
-3.42gpm
n=60
8.27gpm
n=7
MPG
-0.03 mpg
n=64
-0.02 mpg
n=59
-0.79 mpg
n=7
Vehicle CDH04 was not included in the calculations of for either OBD or EVI240 since no FTP
results were available.
Vehicles that failed the LAB240 with the MIL illuminated were repaired based mainly on the
OBD codes and therefore are not completely independent of OBD effects. Another way to look at
the same repair reductions is to quantify the total grams per mile reduced over the study and not
on a per vehicle average. This is reflected in Table 8.
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Table 8: Summation of reductions associated with OBD repairs and IM240
LDV
Summation reduction
for OBD repair
Summation reduction
for IM240 repair
LOT
Summation reduction
for OBD repair
Summation reduction
for IM240 repair
THC
15.8 gpm
7.2 gpm
THC
7.5 gpm
5. 9 gpm
NMHC
11.1 gpm
4.5 gpm
NMHC
2.6 gpm
1.8 gpm
CO
303 gpm
108 gpm
CO
102 gpm
73 gpm
NOx
12.0 gpm
3.9 gpm
NOx
8.2 gpm
4.2 gpm
CO2
737 gpm
103 gpm
CO2
-170 gpm
58 gpm
MPG
-60 mpg
-16 mpg
MPG
-2 mpg
-5 mpg
The ability of OBD systems to identify components which are not functioning properly, even
when the vehicle was emitting below applicable standards, was investigated in this study. Table 9
lists the result of maintenance performed on vehicles with tailpipe emissions below the applicable
certification standards.
Table 9: Maintenance aspect of OBD MIL illumination identification
LDV
LOT
Total
MIL on/passing FTP
88
48
136
malfunctioning part
found
63
34
97
Unable to duplicate
malfunction (MIL
extinguished)
25 (3)
14 (6)
39 (9)
See appendix 4 for a list of parts replaced
During this test program 5 vehicles without MIL illuminations were found to have tailpipe
emissions exceeding both their applicable standards and the 1.5 times target trigger level for MIL
illumination. These vehicles are listed in Table 10 with the cause of their high emissions. Two of
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these vehicles are post OBD repairs for MIL illumination (ATL130 and ATL120). These two
vehicle's emissions remained above the trigger level even after all reasonable diagnostics had
been completed.
Table 10: Discussion of specific vehicles
Vehicle
FTP Emissions
Problem found
CDH03; 1996 Chrysler
Neon, odometer 86236
LANE IM240 failure
As-Received
FTP:THCCO NOX
1.73 52 0.25
OBD error of omission; unanticipated
oxygen sensor failure; later model years
have revised logic which would have
illuminated MIL
CDH04; 1996 GM S10
Pickup Truck, odometer
27,063
LANE IM240 failure
Could not be driven
on FTP
Projected FTP failure
(See appendix 6, table
X2)
OBD commanding MIL on but electrical
short caused no MIL illumination; Scan
of system showed MIL commanded
"On". This vehicle would be identified
in an OBD I/M scenario.
CDH33; 1997 Daimler-
Chrysler 1500 Pick-up
truck, odometer 113,543
LAB IM240 failure
As-Received
FTP:THCCO NOX
0.55 12.8 2.9
THC level is below 1.5 times
certification standard (NMHC is
unknown) but CO and NOx are over 1.5
times. See discussion of catalyst monitor
ATL130; 1996Isuzu
Hombre (GM certified
system) 23 5K odometer
MIL on prior to repair; off
after repairs.
Post Repair
FTP:THCCO NOX
0.5 17.1 0.6
OBD repair did not return vehicle to
below 1.5 times certification standards
(HC below CO is over) See discussion
on catalyst monitor.
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ATL120; 1997 GM Gr
Am odometer 47,173
MIL on prior to
diagnostics
Post Repair
FTP:THCCO NOX
0.14 1.6 1.0
No problem found during diagnostics
(HC and CO below trigger levels for
OBD; NOx above OBD trigger level)
LDV CDH03 from the table above is considered an OBD error of omission due to the emissions
levels and the lack of MIL illumination. The repair of the oxygen sensor returned this vehicle to
acceptable emissions level. Further investigation of this problem by Daimler-Chrysler engineers
found an unanticipated failure mode of the rear oxygen sensor. Daimler-Chrysler found that this
failure mode would be detected by all later OBD systems in their product line. No additional
examples of this type of oxygen sensor failure mode were located in this test program. LOT
CDH04 is not considered an OBD error for this study since the OBD computer was commanding
the MIL to be illuminated, but the nature of the problem (short in the electrical system) would not
allow the MIL to illuminate. This type of problem would be caught by scanning the OBD system,
as opposed to just a visual check of the MIL (as required by EPA regulations). LOT CDH33,
LDT ATL130 and LDV ATL120 fall into a category of OBD error of omission that is allowable
under the current OBD regulations. Each of these vehicles appears to have emissions problems
(CO and NOx) due to catalyst efficiency losses (this is based on evaluation of the emission control
systems on each vehicle). These vehicles do not exceed the HC trigger level, which is used as the
monitor for loss of catalyst efficiency11, therefore, these systems are not in violation of the OBD
requirements. In this study, due to the lack of a detailed (complete bench analysis of each
emission component) analysis of the entire emissions system, it was not possible to say for certain
that these CO and NOx problems were exclusively due to loss of catalyst efficiency. Extensive
engineering analysis of the engine controls and catalyst system would be required to address this
area. This was beyond the scope of this study.
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Recruitment of vehicles from IM lanes with excessive emissions and no MIL resulted in a very
low number of vehicles in this program. As shown in Table 11, we recruited 17 vehicles that had
failed the LANE240 with no MIL illumination. Fifteen (15) of the 17 passed the LAB 240. We
gathered no FTP data on the 15 since the purpose of this area of the test program was to find
vehicles with high emissions and no MIL illumination.
Table 11: Attempts at I/M lane procurement
Failed LANE IM240/No MIL
17
Passed LAB EVI240
15
All 17 vehicles failed the LANE EVI240 for CO; seven (7) failed exclusively for CO .
Discussion of results:
The vehicle sample from this test program has several aspects which should be noted. First,
LDVs are over represented in comparison to LDTs (132 to 69 respectively). This may be due to
the LDTs having lower emissions relative to their less stringent emissions standards. Since most
of these LDT's emission control systems are very similar to LDV systems, manufacturers may
have made the OBD systems less sensitive to specific component degradation. This would cause
less MIL illuminations for LDTs than for similar LDVs. Also, because LDTs have higher
allowable tailpipe emissions (but similar emission control systems) than LDVs, normal
degradation of the emissions to high levels should take longer. How or if this impacts conclusions
from this study is not known at this time. Congruent with this fact is the matter of the low age of
the fleet of vehicles being evaluated. Because of the short period these vehicles have been in use,
procurement for this program was difficult and average mileage low (37,000 miles). We do not
believe that this should impact conclusions being drawn from this study since the OBD system is
for the most part a software/solid state system and not subject to ageing impacts. The main
impact of the newness of these vehicles is in the cost of procuring study vehicles and limited
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exposure of input and control hardware to real world effects (heat, cold, water, salt). Continued
study of this fleet as it ages and accumulates mileage is recommended but little data exists to draw
any meaningful conclusions regarding these impacts at this time (EPA is completing a high-
mileage study of OBD vehicles in the fall of 2000). The possibility exists that synergistic effects
of multiple components aging may impact the OBD systems ability to detect vehicles which have
high emissions. At this time no evidence suggests this possibility will cause dramatic change in
OBD's usefulness for I/M.
Within this study, the sample of Honda and Toyota are under represented due to difficulty in
finding vehicles made by these manufacturers which met the acceptance criteria. One explanation
for this may be that both manufacturers have a reputation of high quality and limited emissions
problems. The possibility remains that the OBD systems on these manufacturers vehicles are not
functioning as required and therefore MIL illuminations are limited. Given the age of the fleet
being evaluated and the limited ability to find Hondas and Toyotas at I/M lanes (Hondas and
Toyotas generally have a low failure rate in I/M), no real conclusion can be reached on these
manufacturer's OBD systems based on these data. More targeted study of these two major
manufacturers appears warranted as their products age. An additional targeted engineering study
could be performed to offer a level of comfort on this matter.
Of the 194 vehicles that were accepted into the program with the MIL on, 43 or 22% were sent
home without any repairs and were listed as "maintenance not required" (MNR). This segment,
which some may characterize as "false failure", requires further explanation. Ten of these vehicles
were sent home because the MIL extinguished before initial testing was completed. Since our
repair goal was to extinguish the MIL, and self extinguishing is normal operation, we had no
more interest in these vehicles and we did no further testing.
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Of the 33 remaining vehicles 30 passed the FTP. Two (ATL94 and ATL98) were below 1.5 times
FTP and one (ATL120) was an acknowledged dirty vehicle, for which we could not find an
appropriate repair. We judge that all 43 of these vehicles had intermittent problems. Almost half
(15) had misfire codes. Misfires are notoriously intermittent and in some cases we were able to
make a vehicle misfire in the lab by spraying the engine compartment with water (similar to real
world conditions). In at least one case we were unsuccessful with this technique even though we
could plainly see where the misfire was occurring from an ignition wire that was not routed
correctly. An additional 11 of the 33 had fuel trim OBD codes which OEM diagnostics failed to
identify a specific cause.
While an argument can be made that these nonrepaired vehicles initially having OBD failures
found in this test program represent OBD's equivalent to the tailpipe false failure, we believe that
this problem is overstated in this study (due to procurement methods which solicited vehicles as
soon as MIL illumination occurred) and that OBD offers a better method of dealing with these
problems than traditional tailpipe I/M. The OBD technology offers the technician the ability to
diagnose the I/M problem directly from the same system that was used to fail the vehicle at the
inspection lane. Additionally, if the technician can not find any problem with the system and the
system does not retrigger the MIL, the technician has a higher level of assurance that the vehicle
will pass the retest at the inspection lane. Smooth implementation of OBD checks in I/M
programs will rely on educating the public, I/M inspectors, and the automotive service industry
about OBD technology.
It is believed that changes to the OBD regulations which make extinguishing MILs easier for
misfire and fuel system problems should reduce this concern (intermittent MILs) on future model
years. These intermittent problems that occur are no different than intermittent problems that
occur on pre-OBD n vehicles and are merely a by-product of engineering applications. OBD is
not designed to eliminate these intermittent problems, only to indicate and provide a possible root
19
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cause for the technician to investigate. It should be acknowledged that these intermittent
problems existed prior to OBD technology and are not created by the technology. These problems
may cause frustration with consumers and technicians but are believed to be a problem which is
addressable through proper education of technicians and owners. Discussions with repair
technicians and members of the Service Technician Society (STS) have shown that the
intermittent misfire and fuel trim problems are being addressed with real field fixes. Anecdotal
evidence indicates that field repairs are limiting the recurrence of these codes.
Conclusions:
From this study we conclude that the OBD technology is a viable I/M test for 1996 and newer
vehicles. The magnitude of emissions reductions available from basing repairs on OBD appear at
least as large, if not greater, than available I/M tailpipe tests. In direct comparison to the EVI240
the OBD technology offers the ability to identify more of the vehicles with tailpipe emissions
which exceed certified standards (see Tables 3, 4, and 5). With only a couple of exceptions OBD
identifies the same vehicles that EVI240 does and additionally identifies components which have
degraded and may cause future emissions problems. While the instantaneous emissions benefits
of identifying and repairing these components are small, long term durability of expensive
components (catalytic converter, fuel injectors, oxygen sensors, transmissions) may be extended
from this type of preventative maintenance. Additionally, we found that OBD repairs effectively
returned vehicles to their proper operating conditions and that tailpipe emissions, for a majority,
returned to below certification levels. The cost of repairs for extinguishing the MIL appears
reasonable with a limited number of exceptions. We believe it is almost impossible to separate
the cost of repairing EVI240 failures from OBD failures since OBD diagnostics are the basis for
almost all emission system repairs on these vehicles and in the field.
While OBD does not appear to identify all of the high emitting vehicles, including a tailpipe test
as part of an I/M test program design in order to catch the small fraction of failures missed by
20
-------
OBD, would be questionable due to cost and air quality benefits associated with the gain. The
probability of false failure with the tailpipe test appears to be high at this time for these vehicles
(model year 1996 and newer). Another problem with tandem testing would be explaining
conflicting test results between the OBD test and the tailpipe test. While there exists many
plausible engineering explanations for conflicting results, the perception problem created with the
general public would not be easily addressed. The high level of confidence in the existing tailpipe
test results could be a barrier to the acceptance of the OBD technology.
The rate of EVI240 lane false failures (15 out of 17) is troubling. Further investigation concerning
EVI240 testing accuracy is justified before any recommendation for tailpipe testing these newer
vehicles is warranted. Current revisions to the EVI240 test cycle (AZ147 cycle) may offer better
results but this is unknown at this time. All previous studies on tailpipe testing effectiveness have
evaluated fleets in general and not the effectiveness on new vehicles specifically. The results
from this test program would support further study of any tailpipe test on this specific technology
group before including a tailpipe test. Other I/M tailpipe tests may have similar or worse
problems with new vehicles. It should be pointed out that in its comparison of the emission
reductions attributable to OBD-I/M versus EVI240, the OBD tailpipe study was biased in favor of
the EVI240 to ensure that the conclusions drawn regarding OBD-I/M relative effectiveness were
conservative. Specifically, when a vehicle was identified as a likely EVI240 false failure based
upon a comparison of LANE240 and LAB240 test results, that vehicle was then dismissed from
further participation in the study. As a result, the gpm emission reductions attributed to EVI240
were not "watered down" down by the false failures noted between the LANE- and LAB240s.
Conversely, potential OBD false failures were included in the sample and were actively recruited.
Therefore, the gpm reductions attributed to either test based upon this pilot really do represent the
"best case" scenario for EVI240 and the "worst case" scenario for OBD-I/M.
21
-------
In this study the cost of performing OBD repairs to extinguish MILs appear accurate and
reasonable in cost. No calculations of cost effectiveness were performed for this report due to the
limited scale of this study and any comparisons would be with fleet cost effectiveness values. The
average repair costs of $252 and $284 for OBD LDV and LDT respectively is higher than the CPI
corrected value for EVI240 repairs from the 1992 I/M regulation of $200. We believe that this is
mainly due to the very small percentage of very expensive repairs found in this study. We believe
that any comparison of cost effectiveness should account for the level of false failures which
occur in tailpipe testing demonstrated in this study. Without adjustments for this concern and life-
cycle analysis of OBD's preventative repairs any comparison is of limited application.
Recommendations:
Several areas of the OBD technology appear to justify further examination. The no malfunction
found vehicles raise concerns of overly sensitive OBD systems that detect problems that cannot be
repaired due to their intermittent nature. This could lead to frustration for vehicle owners and
technicians and could impact acceptance of OBD technology. In this study, the prevalence of this
problem may be overstated due to the nature of recruitment (vehicles were very hard to find and
vehicles were recruited as soon as MILs were illuminated). In a "real world" scenario, many of
these vehicles would have had the MIL extinguished naturally through normal driving (none of
the vehicles which had their MIL extinguish during the test program were procured from the I/M
lanes, which adds credence to this hypothesis).
The OBD catalyst efficiency monitoring requirements appear to offer somewhat of a window for
vehicles to exceed their tailpipe emissions levels for CO and NOx without any MIL illumination.
It is unknown from this study if the vehicles which failed for CO and NOx due to apparent
catalyst problems would eventually illuminate the MIL based on loss of efficiency for HC.
Further study in this area appears justified and the assumptions in monitoring catalysts should be
22
-------
revisited for possible refinement. Along these lines CARB has proposed OBD regulation changes
which would address catalyst NOx conversion efficiency12.
This test program was run on vehicles which are relatively new and therefore can not address the
impacts of time on these systems. While care was taken not to test vehicles with little or no
mileage accumulated, nothing can substitute for exposure of these systems to seasonal changes
and mass of fuel through the systems which come with natural aging. Based on this we feel that
further monitoring of this technology as it ages is advised. With this understood, we believe that
this technology has demonstrated an ability to identify vehicles with high emissions or defective
components which is as good or better than available tailpipe tests at this time. Additional study
of this technology as mileage is accumulated and as time passes is advised in order to offer
continuing confidence in this method of identifying vehicles in the fleet which should be repaired.
Vehicles that were not adequately represented in this study, i.e. Hondas, Toyotas, and to some
degree trucks, should be also be investigated further.
23
-------
Appendix:
1 Regulatory Summary
The following discussion provides a summary of the regulatory history and the current regulatory
requirements for EPA's OBD program. A detailed discussion of the specific EPA OBD
requirements that manufactures are required to comply with are contained in the Federal Register
(58 FR 9468 for '94-'97 model years, 63 FR 7081 for '98 and later model years). CARB OBDII
requirements can be obtained from the California Air Resources Board. The documents cited
throughout this discussion are available on EPA's OBD Web site at
"www.epa.gov/oms/obd.htm". CARB documents can be found at "www.arb.ca.gov".
On February 19, 1993, the EPA published a final rulemaking (58 FR 9468) requiring
manufacturers of light-duty vehicles (LDV) and light-duty trucks (LDT) to install on-board
diagnostic (OBD) systems on such vehicles beginning with the 1994 model year. The regulations
promulgated in that final rulemaking require manufacturers to install OBD systems that monitor
emission control components for any malfunction or deterioration causing certain emission
thresholds to be exceeded. The regulations also require that the driver be notified of the need for
repair via a dashboard light when the diagnostic system has detected a problem. Under these
regulations, a vehicle's OBD system must be capable of detecting a malfunction or deterioration of
emission-related components before such a malfunction or deterioration individually causes an
emission increase greater than certain thresholds. For example, the OBD system must identify
catalyst deterioration before it results in both exhaust emissions greater than 0.6 g/mi THC and an
exhaust emission increase of greater than 0.4 g/mi THC. As mandated by the Clean Air Act
Amendments of 1990, the original Federal OBD regulations required manufacturers to monitor
the catalyst, oxygen sensors and to detect misfire. The 1993 regulations also required
manufacturers to monitor for evaporative system leaks and for any other component malfunction
or deterioration that could impact emissions.
24
-------
The 1993 regulations provided that manufacturers could certify to CARB OBDII requirements to
meet Federal OBD requirements, which in most cases are at least as stringent as the Federal OBD
requirements. This compliance option was available to manufacturers through the 1998 model
year. The 1993 requirements are applicable to MY 1994-1998.
On December 22, 1998 (63 FR 70681), EPA promulgated a final rulemaking to update the
original Federal OBD regulations finalized in 1993. One of the primary goals of the 1998
regulation was to redesign the Federal OBD requirements such that they more closely resembled
the CARB OBDII requirements. As a result, EPA moved the Federal OBD program away from
the additive threshold approach and adopted aspects of CARB multiplicative approach. In other
words, OBD systems would be required to monitor deterioration and malfunction of emission-
related components at 1.5 times the applicable standard for HC, CO, and NOx. In addition, the
Federal OBD monitoring requirements were expanded from the 1993 list (this reflected EPA's
requirement from the CAA to move to an OBD system check to enhance or replace traditional
tail-pipe tests in Inspection/Maintenance programs).
The 1998 regulations extended indefinitely the CARB OBDII compliance option to manufacturers
beyond the 1998 model year. However, EPA is required to update its regulations whenever
CARB finalizes changes to their regulations. EPA will publish a Federal Register notice in these
instances announcing the adoption of the latest CARB changes and will invite comment from
interested parties. The changes finalized in the 1998 regulations are applicable to 1999 and later
model years.
25
-------
2 Test Sequence Used at Laboratories
i. Procurement and acceptance into the program
ii. LA-4 cycle (preconditioning for IM240 test)
iii. IM240 test
iv. Drain in-use fuel
v. Fill with indolene (40% fill)
vi. LA-4 cycle (preconditioning for FTP test)
vii. 12 hour soak (no diurnal heat build)
viii. FTP test (no evaporative test)
ix. EVI240 test
x. Repair if necessary
xi. OBD Readiness flags cleared thru operation of vehicle
xii. Repeat starting at iv
3. Estimating Costs
Repair information for vehicles was reported in several different ways. Some work invoices listed
the parts that were replaced or the repairs that were made with no indication of cost, others listed
the cost of the parts only, while some work invoices listed only the total cost of the repair with no
breakdown of parts and labor. Many of the vehicles in the test program were still under warranty
and were sent to the dealers for repair. In most of those cases, since there was no charge, there
was no cost information. Information was gathered from dealerships to assign repair costs in
these cases.
To assign a cost to each vehicle we took the following steps:
I/ List of all the "hard" data, (labor hours, labor charge, parts charge, total charge)
II The miscellaneous charges were added as though they were labor or parts
3/ The labor rate was assumed to be $70 per hour. (Actual rates varied from $50 to $70)
4/ The number of labor hours can now be calculated from the labor cost data and this is
added to our table of "hard" data.
26
-------
5/ For multiple repairs that are similar (O2 sensors is the best example) we averaged the
parts and labor hours and assigned those values to the vehicles that have no cost data available.
61 Where we had no "hard" data for labor hours we used the composite judgement of
several people that were experienced in these repairs.
II All vehicles for which there were no problems found were assigned one hour labor, in
the absence of other data, under the assumption that most shops would charge that amount for the
DTC scan
We believe this approach to be as conservative as possible, biasing the cost data, if at all, to the
high side.
27
-------
4 Broken parts
A breakdown of the broken parts found for vehicles with passing FTP scores and a MIL
illumination is in Table XI.
Table XI: Broken Parts Found with Passing FTP emissions
Systems/Components
O2 Sensor
EGR.System
Ignition System (spark plugs, ignition wires, other)
Transmission related components
PCM, Reprogram or Replace
Wire Harness problems
Engine, Mechanical (cylinder head, harmonic balancer, valve springs)
Vacuum Leaks
Thermostat, Cooling System
Fuel Pump
Cam Sensor
Secondary Air Combo Valve
Throttle Position sensor
Exhaust Leak
Mass Air Flow sensor
Intake Air Controller
Evaporative emissions valve
Catalyst
LDV
11
4
10
3
10
6
1
4
1
2
2
2
1
0
1
1
1
3
LOT
15
6
1
4
1
1
1
2
0
0
0
0
1
1
0
0
0
1
28
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5 Lane IM240 and Lab IM240
There are a number of differences between the way an IM240 test is conducted in an inspection
lane and the way that the test is conducted in an emissions laboratory. Some of them are:
I/ quality of the test equipment
II frequency of calibration of test equipment
3/ skill of technician
4/ control of ambient conditions
5/ control of tire pressure
61 operating temperature of the vehicle
The first five items are of critical importance for a certification test in the laboratory but it is our
opinion that they are diminished in comparison to the last item for I/M testing.
By far the greatest importance is item six. There is a large variation in emissions between a partly
warmed vehicle and a fully warmed vehicle. In the laboratory an LA4 (1372 seconds ) test cycle
is run before the LAB240 test to assure that the engine is fully warmed up and the catalyst hot.
Vehicles arriving at I/M inspection lanes are assumed to be at operating temperature due to the
driving prior to arrival at the lane (this may or may not be true). Attempts have been made in I/M
systems to address this preconditioning problem through various methods.
29
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6 Non-Testable Vehicles
Table X2 is a description of why each vehicle was not testable and why the FTP is assumed to be
over the applicable standards.
Table X2: Description of Vehicles/Trucks Assumed to Fail FTP
Vehicle
FTP dynamometer concerns
Available data
CDH4, 1996 S-10
Pickup MIL off
(computer
commanding MIL
"On")
Truck could not accelerate and would
stall in 3rd gear on FTP
Lab EVI240 results:
(THC/CO/NOx)
11.8/147/0.02
Black plume of smoke from
tailpipe
ATL78, 1999
Malibu
MIL illuminated
74,000 miles
EVI240 test of the vehicle caused
closure of test cell due to hydrocarbon
contamination of instruments.
Decision made to not run FTP.
Lab EVI240 results:
32.1/45.6/0.14
Raw fuel out of the tailpipe
during testing
7 Vehicle ATL 90
ATL 90, a GM Cheyenne truck.- The transmission of this high mileage truck had been replaced
with an incorrect transmission and so is technically a case of tampering. However the truck was
clean and the difference between the two transmissions was, in our opinion, insignificant for
operation or emissions but was such that the computer was not compatable with the transmission.
The only possible repair was replacement of the transmission at high cost ($2,000) for no benefit
and therefore no repair was performed.
30
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Reference
1. SAE paper 962091; "Preconditioning Effects on I/M Test Results Using IM240 and ASM
Procedures. Heirigs, Philip; Gordon, Jay
2. Federal Register Volume 61, No. 152; August 6, 1996; page 40940
3. Mobile Source Technical Review Subcommittee meeting of'1116191
4. Sierra Research Report under EPA Contract 68-C4-0056; WA 2-03; "Development of a
Proposed Procedure for Determining the Equivalency of Alternative Inspection and Maintenance
Programs" page 7.
5. Automotive Industries; page 17; February, 1998,.
6. "Recommended Practice for Diagnostic Trouble Code Definitions" SAE J2012; Society of
Automotive Engineers, Inc.; Revision date March 1999.
7. "Analysis of the OBDII Data Collected From The Wisconsin I/M Lanes", Ted Trimble,
Environmental Engineer, U.S. EPA, August, 2000.
8. "EPA I/M Briefing Book; Everything You Ever Wanted to Know About Inspection and
Maintenance"; EPA-AA-EPSD-IM-94-1226, Section Four, page 10; United States
Environmental Protection Agency, Office of Air and Radiation, February 1995
9. For LDVs: 40 CFR Part 86.096-8 (a)(l); for LDTs: 40 CFR Part 86.097-9 (a)(l)
10. Clean Air Act, Section 182 (c)((3)(C)(iii); July 1992
11. California Air Resources Board Regulation "Malfunction and Diagnostic System
Requirements, 1968. l(b)(l.2.1 - 1.2.4)
12. California Air Resources Board, MSC 99-12, Notice of Proposed Regulation Changes to
1968.1(b)(1.2.4)
31
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lab Vehicle nuiYr
Make
engi
Model Size odometer
liters m
ARB
ARB
ARB
ARB
ARB
ARB
ARB
ARB
ARB
ARB
ARB
ARB
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
1
2
3
4
5
6
7
8
9
10
11
12
1
2
3
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
21
22
24
25
26
98 GM
98 DC
97 DC
98 ford
97 GM
97 Suzuki
98 honda
98 hyundai
97 ford
98 honda
97 honda
97 DC
97 GM
97 GM
98 Nissan
97 DC
97 DC
97 GM
97 Nissan
96 GM
97 SUZUKI
97 Hyundai
98 DC
98 Ford
98 DC
97 Nissan
96 Ford
96 GM
98 Nissan
98 Hyundai
96 Ford
97 DC
98 DC
98 Ford
98 FORD
Lumina
breeze
neon
contour
camero
metro
accord
accent
aspire
civic
accord
intrepid
Malibu
Grand Am
Sentra
Sebring
Neon
Grand Am
Maxima
Lumina
Metro
Elantra
Breeze
Contour
Neon
Sentra
Mustang
lumina
Altima
Sonata
Contour
Neon
Stratus
Taurus
Grand Mar
3.1
2.4
2
2
3.8
1
2.3
1.5
1.3
1.6
2.2
3.5
3.1
2.4
1.6
2.5
2
2.4
3
3.1
1.3
1.8
2
2
2
1.6
3.8
3.1
2.4
2.4
2
2
2.4
3
4.6
lies
5844 initial
final
40 initial
final
25148 initial
final
29407 initial
final
21 806 initial
final
22779 initial
final
2259 initial
final
16528 initial
final
20702 initial
final
654 initial
final
23199 initial
final
23534 initial
final
15386 initial
final
22717 initial
final
309 initial
final
14036 initial
final
18232 initial
final
21729 initial
final
18897 initial
final
40698 initial
final
19764 initial
final
13373 initial
final
2774 initial
final
4737 initial
final
9468 initial
final
22470 initial
final
14823 initial
final
70600 initial
final
29 initial
final
3650 initial
final
41427 initial
final
25862 initial
final
3178 initial
final
1497 initial
final
6516 initial
F
THC nmHC CO
gr/mi gr/mi c
0.287
0.116
0.092
0.091
0.072
0.066
0.129
0.129
0.118
0.118
0.894
0.086
0.113
0.111
0.182
0.182
0.572
0.071
0.143
0.143
0.174
0.174
0.076
0.076
0.083
0.083
0.1
0.089
0.131
0.133
.20
0.20
0.084
0.084
0.186
0.176
0.129
0.138
0.13
0.13
0.091
0.07
0.112
0.112
0.098
0.08
0.09
0.09
0.08
0.18
0.15
0.06
0.07
0.29
0.07
0.04
0.03
0.04
0.04
0.06
0.06
0.12
0.08
0.09
0.11
0.06
0.06
0.12
0.12
0.24
0.10
0.08
0.08
0.07
0.06
0.12
0.12
0.11
0.11
0.86
0.08
0.10
0.10
0.16
0.16
0.52
0.06
0.13
0.13
0.15
0.15
0.07
0.07
0.07
0.07
0.09
0.08
0.11
0.12
0.17
0.17
0.08
0.08
0.17
0.16
0.11
0.11
0.12
0.12
0.08
0.06
0.10
0.10
0.09
POST FTP
T P 240
Nox OBD PcodTHC CO Nox repairs
)r/mi gr/mi gr/mi
1.0
1.4
1.7
1.4
2.4
3.1
0.9
1.0
4.4
1.6
2.0
0.5
0.7
0.7
0.6
0.6
1.6
0.9
0.8
0.7
1.0
1.0
1.1
1.3
2.7
1.5
1.3
1.3
1.3
1.3
0.9
0.9
0.8
0.8
2.5
1.2
1.3
0.9
2.4
2.4
9.9
0.7
0.7
0.7
2.0
2.0
2.1
2.1
0.8
0.8
0.7
1.2
1.7
1.7
2.5
2.5
0.7
0.7
1.2
1.1
1.2
1.2
0.9
0.9
1.8
1.7
1.1
1.1
1.2
0.08 302
0.06
0.03 700
0.03
0.12 703
0.19
0.09 133
0.10
0.84 102
0.12
0.09 113
0.10
0.04 135
0.04
0.13 1614
0.13
0.39 420
0.10
0.06 118
0.05
0.12 740
0.12
0.13306
0.23
0.58 420
0.09
0.60 300
0.54
0.17400
0.11
0.14 740
0.14
0.17300
0.17
0.27 300
0.40
0.48 174
0.16
0.25 300
0.25
0.14 113
0.07
0.16 136
0.17
0.35 300, 304
0.35
0.12302
0.12
0.07 305
0.07
0.12 136
0.07
0.10304
0.08
0.56
0.56
0.01 300
0.01
0.18 400
0.17
0.17301,302,3
0.16
0.17304
0.17
0.07 401
0.09
0.06 500
0.06
0.04 122,1120
0.00
0.01
0.03
0.01
0.01
0.01
0.02
0.01
0.10
0.01
0.01
0.00
0.01
0.01
0.06
0.02
0.07
0.06
0.01
0.03
0.02
0.12
0.01
0.01
0.02
0.02
0.02
0.03
0.0
0.01
0.01
0.03
0.03
0.05
0.30
0.03
0.02
0.02
0.09
0.02
0.02
0.01
0.02
0.02
0.02
0.05
0.01
0.00
0.01
0.03
0.03
0.02
0.01
0.00
0.01
0.01
gr/mi gr/mi
0.135
0.152
0.373
0.202
0.31
0.23
0.982
0.242
1.213
0.279
2.833
0.775
0.323
0.176
3.125
0.281
2.86
0.674
0.352
0.115
0.023
1.12
0.04
0.15
0.2
0.64
0.69
0.16
0.13
0.26
0.08
0.55
0.16
0.48
6.48
0.16
0.1
0.06
1.53
1.75
0.1
0.2
0.61
0.24
0.36
0.45
0.13
0.08
0.08
0.7
0.7
0.23
0.21
0.2
0.06
0.09
0.02 repair loose plug wire, #2 cyl
0.18
0.00 loose wire, tcm to relay
0.01
0.12 brake switch new head
0.15 new injectors clean plugs
0.11 mil off prep #1, fixed fuel leak
0.11 new O2 sensor
0.75 new MAF sensor,new cat
0.01
0.06 repair IAT circuit/sensor wires
0.05
0.01 npf; fuel trim
0.12 npf;
0.42 cat replaced, front O2 senson
0.33 rear O2 sens mistakenly replaced
0.04 overheating on road
0.06 remove plastc shield from radiator
0.06 npf
0.16 spark plug replaced,
0.11
0.61 Replaced Ign. Module, rearO2, .
0.01 cat replaced,
0.94 Replaced Oil Pump.
0.81
0.17 Replaced EGR
0.11 back pressure tube
0.09 npf; transmission
0.08 npf; misfire
0.49 Replaced Oil Pump.
0.68
0.31 Replaced front O2 sensor
0.16 replace egr tube gasket
0.21 npf; misfire
0.01 Repaired broken IAT wires
0.16
0.09 Replaced rear O2 sensor.
0.17
0.57 npf; misfire
0.14 npf; misfire
0.06 npf; misfire
0.03 Replaced O2 sensor
0.08
0.08 reinstall Spark plug boot on #4
0.03
0.45 fail state l/m NPF
0.01 npf; misfire
0.07 Install vacuum signal line
0.05 to egr
0.19 repaired Capacitor wire at coil
0.13
0.05 npf; misfire
0.0 New PCM
0.1
0.0 npf; vehicle npf
0.01 TPS had been replaced once before. Vehicle takf
hours parts
labor $
1
2
2.5 70
4 400
2
1
1
3 350
0.5
1
1 2
4 620
2.5 45
2 2.5
1
1
2.5 45
2 85
1
1.5
1.5 70
1
1
1
1.5 70
1
1
1.5
1.5
1
1.75 200
1
1
labor
$
70
140
175
280
140
70
70
210
35
70
70
280
175
140
70
70
175
140
70
105
105
70
70
70
105
70
70
105
105
70
122.5
70
70
total
$
70
140
1838
245
680
140
70
70
560
35
70
72
900
220
142.5
70
70
220
225
70
105
175
70
70
70
175
70
70
105
105
70
322.5
70
70
-------
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
27
30
31
32
35
37
40
43
44
49
50
53
56
59
60
61
62
63
64
65
66
68
69
71
73
74
75
76
77
78
79
81
83
87
89
91
96
97 Honda
98 Ford
96 GM
98 Ford
98 GM
97 GM
96 niss
98 Toyota
98 GM
98 GM
98 GM
98 Ford
98 FORD
96 GM
96 Ford
99 Toyota
96 Ford
98 Ford
99 GM
99 DC
99 GM
98 GM
99 Toyota
97 Kia
99 Nissan
98 Ford
99 Nissan
99 GM
99 Ford
99 gm
99 Toyota
99 GM
99 GM
96 GM
99 GM
99 GM
99 DC
Civic
Taurus
Lumina
Taurus
LeSabre
Achieva
sentra
Camry
Camaro
Regal
88 LS
Escort
Tracer
Cierra
Taurus GL
Camry
Taurus
Taurus
Malibu
Breeze
Regal
Camaro
Camry
Sephia
Infiniti Q45
Taurus
Altima
Gr. Am
Contour
malibu
Camry
Malibu
Lumina
Cavalier
Cavalier
Intrigue
Sebring
1.6
3
3.1
3
3.8
2.4
1.6
2.2
3.8
3.8
3.8
2
2
3.1
3
2.2
3
3
3.1
2
3.8
3.8
2.2
1.6
4.1
3
2.4
3.4
2
3.1
2.2
3.1
3.1
2.2
2.2
3.8
2.5
final
10570 initial
final
5475 initial
final
29197 initial
final
6496 initial
final
15916 initial
final
29233 initial
final
31 366 initial
final
440 initial
final
20051 initial
final
27501 initial
final
15239 initial
final
7424 initial
final
24066 initial
final
54355 initial
final
91173 initial
final
9795 initial
final
55296 initial
final
17567 initial
final
7834 initial
final
9535 initial
final
6443 initial
final
9448 initial
final
11508 initial
final
32048 initial
final
7252 initial
final
19410 initial
final
10146 initial
final
23208 initial
final
5860 initial
final
7400 initial
final
12848 initial
final
7064 initial
final
8896 initial
final
93575 initial
final
4465 initial
final
10202 initial
final
951 4 initial
0.091
0.068
0.068
3.099
0.105
0.241
0.241
0.121
0.104
0.08
0.08
0.118
0.118
.15
$0.15
0.114
0.106
0.174
0.074
0.071
0.07
0.277
0.079
0.059
0.078
0.052
0.04
0.181
0.171
0.167
0.146
0.063
0.063
0.124
0.124
0.104
0.103
0.126
0.12
0.145
0.082
0.057
0.054
0.085
0.082
0.079
0.079
0.103
0.081
0.148
0.144
0.123
0.115
0.075
0.072
0.224
0.109
0.1
0.059
.08
0.083
0.052
0.135
0.126
0.278
0.076
0.164
0.147
0.192
0.09
0.08
0.08
0.08
0.05
0.05
2.63
0.09
0.21
0.21
0.10
0.09
0.07
0.07
0.10
0.10
0.14
0.14
0.10
0.10
0.14
0.06
0.06
0.06
0.25
0.06
0.05
0.07
0.05
0.04
0.16
0.15
0.13
0.12
0.05
0.05
0.10
0.10
0.09
0.09
0.10
0.10
0.13
0.07
0.05
0.05
0.07
0.07
0.07
0.07
0.08
0.07
0.13
0.13
0.10
0.10
0.06
0.07
0.21
0.09
0.08
0.05
0.1
0.1
0.0
0.1
0.1
0.2
0.1
0.1
0.1
0.2
0.1
0.1
0.07
1.0
1.6
1.6
122.0
1.4
3.3
3.3
1.2
1.2
0.9
0.9
2.6
2.6
0.8
0.8
1.2
1.2
3.0
1.3
1.1
1.3
1.4
1.1
1.2
0.7
0.9
0.5
1.9
1.9
2.6
1.4
0.9
0.9
1.4
1.4
1.2
1.2
1.3
1.4
1.9
0.7
1.1
1.0
0.9
0.7
1.2
1.2
1.3
0.9
1.5
1.4
1.3
1.1
1.2
1.0
0.9
1.3
5.9
1.3
0.8
1.2
0.4
1.2
1.5
2.9
0.9
1.8
1.7
5.5
1.6
1.0
1.1
0.06
0.04 302, 304, 1
0.04
0.07 172, 175
0.10
0.50
0.50
0.07 161
0.08
0.16300
0.16
0.17503
0.17
0.28
0.28
0.22 401
0.14
1.31 120,135, 1
0.21
0.24 131
0.24
0.13304
0.14
0.10 171
0.09
0.12 1504
0.07
0.35 1406,300
0.33
0.51 340
0.34
0.15 1133
0.15
0.32 1504,153
0.32
0.09 1309
0.08
0.16301
0.13
0.20 136
0.14
0.09 131
0.10
0.06 306
0.07
0.14 1133
0.14
0.30 420
0.05
0.42 505
0.19
0.10 1309
0.08
0.06 740
0.05
0.27 113
0.18
0.05 1131
0.10
201,301
0.09
0.15 1133
0.08
0.14 131,306
0.12
0.53 420
0.09
0.22 141
0.17
0.05 1133
0.07
0.21 131, 1887
0.12
171
0.01
0.04
0.03
0.01
0.06
0.01
0.02
0.02
0.03
0.02
0.02
0.00
0.01
0.03
0.02
0.01
0.01
0.01
0.06
0.04
0.06
0.04
0.02
0.05
0.02
0.04
0.01
0.04
0.02
0.00
0.02
0.03
0.01
0.03
0.01
0.04
0.02
0.01
0.01
0.02
0.91
0.02
0.01
0.02
0.00
0.21
0.01
0.12
0.10
0.10
0.09
0.04
0.01
0.05
1.07
0.16
0.09
1.54
0.02
0.42
0.2
0.3
0.05
0.15
0
0.28
0.09
0.16
0.58
0.41
0.08
0.95
0.41
2.76
1.06
0.35
0.67
0.1
0.02
0.02
0.59
0.2
0.1
0
0.05
0.28
0.58
0.04
0.06
0.04
0.27
0.06
0.01
73.3
0.29
0.07
0.12
0.01
2.4
0
0.91
0.76
6.34
6.06
0.6
0.2
0.00
0.03 npf; misfire
0.05 Replaced sending unit
0.08
0.48 failed state I/M test, npf
0.06 Replaced Fuel Sending Unit
0.02
0.19 npf; misfire
Replaced VSS & Gear
0.09 fail state l/m
0.16 Replaced EGR vacuum line
0.08
0.06 Repaired Shorted Wiring
0.18 npf; fuel trim
0.22 spark plug and wire replaced
0.12
0.1 1 replace manifold vac. hose
0.13 r/r vent sol reprogram
0.03
0.13 computer replaced
0.29
0.45 replace camshaft sensor and
0.32 drive shaft
0.09 npf, fuel trim
0.31 npf; fuel trim
0.32 R/R pcm and throttle valve
0.16 npf; misfire
0.22
0.16 replaced o2 sens and F.P. relay
0.10
0.01 replaced o2 sens
0.06 reprogram PCM
0.05
0.05 npf; fuel trim
0.37 replace exhaust, ox sensor
0.01 and catalyst
0.33 idle air control motor
0.05 new PCM
0.01 tfans,pcm new
0.03
0.35 wiring at ECT
0.05 light went out, battery went dead
no initial ftp wiring at #1 injector
0.07 R/R MAF
0.03
0.26 R/R O2 B1S1
0.14
0.61 R/R cat
0.07
0.26 R/RB1S1 O2
0.18
0.01 light went out; fuel trim
0.00
0.18 R/R O2
0.18
fuel pump
1
2
1
1
1.5
npf 1
NPF
0.5
1.5
1
1.5
1.5
1.6
2
2
1
1
2.1
1
2
1.5
1.2
1
3
1.75
1.8
2
1.5
1
1
1.5
1.5
2
1.5
1
1.5
1.75
50
50
12
70
10
24
3
36
200
125
344
100
70
550
95
200
250
110
70
300
73.08
15
70
95
70
140
70
70
105
70
35
105
70
105
105
112
140
140
70
70
147
70
140
105
84
70
210
122.5
126
140
105
70
70
105
105
140
105
70
105
122.5
70
190
70
120
117
140
45
105
70
129
108
148
340
265
70
70
491
70
240
175
84
70
760
217.5
326
390
105
70
70
215
175
440
178.08
85
175
217.5
-------
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
95
98
100
101
102
103
104
105
106
108
110
111
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
131
1
2
6
7
10
11
12
13
97 Mazda
99 GM
97 Ford
99 toyota
99 Saab
98 GM
97 Ford
99 GM
99 Ford
98 FORD
98 Ford
99 DC
98 Ford
99 GM
99 DC
99 Ford
99 FORD
99 GM
97 SUZUKI
97 GM
99 DC
99 GM
97 ford
99 honda
99 GM
98 GM
98 gm
96 gm
98 gm
98 DC
97 vw
98 GM
97 HONDA
97 ford
98 GM
98 GM
97 vw
626
Gr. Am
Aspire
cam ray
9-3
Cavalier
Taurus
regal
Mustang
Tracer
Escort
Intrepid
Escort
Grand Am
Stratus
Escort
Sable
Cavalier
Metro
Grand Am
stratus
DeVille
Escort
Accord
Intrigue
sunfire
sunfire
Lumina
Cavalier
breeze
passant
deville
ACCORD
aspire
sunfire
cavalier
passant
2
2.4
1.3
2.2
2
2.2
3
3.8
3.8
2
2
2.7
2
3.4
2.4
2
3
2.2
1.3
2.4
2.4
4.6
2
2.3
3.8
2.2
2.2
3.1
2.2
2
2.8
4.6
2.2
1.3
2.2
2.2
2.8
final
36596 initial
final
15618 initial
final
24936 initial
final
11575 initial
final
19237 initial
final
27140 initial
final
52650 initial
final
15563 initial
final
13701 initial
final
201 37 initial
final
26205 initial
final
14664 initial
final
351 77 initial
final
12921 initial
final
19475 initial
final
151 04 initial
final
5596 initial
final
20432 initial
final
55195 initial
final
47,173 initial
final
17000 initial
final
18900 initial
final
71 000 initial
final
5000 initial
final
28000 initial
final
31606 initial
final
26000 initial
final
34769 initial
final
31 424 initial
final
2405 initial
final
23437 initial
final
9495 initial
final
17155 initial
final
3841 8 initial
final
13766 initial
final
16660 initial
final
38278 initial
0.1
0.11
0.11
0.24
0.24
0.19
0.17
0.07
0.07
0.13
0.14
0.27
0.13
0.14
0.13
0.096
0.051
0.18
0.077
0.052
0.054
0.073
0.054
0.328
0.121
0.053
0.047
0.328
0.084
0.227
0.067
0.058
0.056
0.28
0.09
0.151
0.16
0.7
0.06
0.14
0.14
0.1
0.09
0.21
0.16
0.08
0.06
0.04
0.04
0.07
0.08
0.12
0.12
0.12
0.1
0.2
0.1
0.28
0.12
0.085
0.071
0.136
0.118
0.23
0.227
0.103
0.103
2.093
0.181
0.092
0.0872
2.434
0.109
0.163
0.08
0.09
0.09
0.18
0.18
0.17
0.16
0.06
0.06
0.12
0.12
0.22
0.10
0.11
0.10
0.08
0.04
0.14
0.07
0.05
0.05
0.07
0.05
0.29
0.10
0.05
0.04
0.30
0.07
0.18
0.06
0.05
0.05
0.25
0.08
0.13
0.14
0.61
0.05
0.12
0.12
0.07
0.07
0.18
0.14
0.07
0.06
0.03
0.03
0.05
0.07
0.09
0.09
0.10
0.08
0.17
0.09
0.25
0.09
0.07
0.06
0.10
0.10
0.21
0.21
0.08
0.08
1.77
0.16
0.08
0.07
2.37
0.09
0.13
1.0
1.1
1.1
4.0
4.0
1.4
1.2
0.9
0.9
1.4
1.8
5.8
3.2
2.3
1.5
1.1
0.9
6.1
0.7
0.5
0.5
1.0
0.6
4.3
0.6
0.6
0.5
2.4
1.4
8.3
1.0
0.5
0.7
1.4
1.1
2.5
3.7
32.3
1.3
1.6
1.6
1.3
1.4
1.6
0.7
1.1
0.8
1.0
1.0
0.8
1.1
5.2
5.1
3.8
2.7
2.5
0.8
4.8
2.8
0.7
0.5
1.3
1.2
1.7
1.8
1.5
1.5
30.3
1.7
1.7
2.1
10.9
2.4
1.7
0.09
0.18 421
0.17
0.13 171, 172,3
0.13
0.15303,505
0.21
0.14 1133
0.14
0.19 1652
0.15
0.12 118
0.08
0.40 340
0.21
0.14 131
0.09
0.08 190,1132,
0.05
0.19 401
0.09
0.14 172
0.07
0.29 161,432, 1
0.28
0.10 172
0.09
0.47 121
0.13
0.15700,733,7
0.09
0.10 135
0.07
0.18 301
0.13
0.04 141
0.04
0.13 113
0.37
0.97 122,1404
0.97
0.09700,731,7
0.10
0.21 742
0.18
0.10 302
0.12
0.03 1259
0.03
0.43 135,140
0.22
0.20 121,404,1
0.07
0.15 141
0.17
0.50 141
0.17
0.08 300
0.11
0.21 401
0.13
0.19 411
0.09
0.16 606, 741
0.14
0.14302
0.14
0.03 302
0.12
0.33 1133
0.13
0.09 302
0.11
0.17 300
0.00
0.04
0.03
0.13
0.06
0.03
0.02
0.01
0.02
0.06
0.04
0.04
0.03
0.01
0.01
0.12
0.01
0.01
0.01
0.02
0.01
0.29
0.04
0.01
0.01
0.01
0.02
0.32
0.02
0.01
0.01
0.02
0.00
0.03
0.02
0.49
0.01
0.02
0.58
0.02
0.05
0.06
0.01
0.01
0.00
0.01
0.01
0.05
0.05
0.06
0.05
0.11
0.02
0.14
0.06
0.03
0.02
0.05
0.03
0.07
0.05
0.05
0.95
0.04
0.02
0.02
1.68
0.03
0.05
0.1
1.1
0.8
2.5
0.9
0.3
0.2
0
0
1.74
1.3
0.2
0.1
0.42
0.16
2.1
0
0.15
0.1
0.51
0.08
6.12
0.23
0.19
0.08
0
0.05
0.4
0.33
0.24
0.03
0
0
0.22
0.2
33.6
0.5
0.4
22.6
0.4
0.2
0.2
0.4
0.3
0.5
0.3
0.5
3.5
3.8
5.2
3.0
3.0
0.0
3.6
1.8
1.4
0.3
0.3
0.3
0.4
0.3
1.0
34.1
0.6
0.8
0.8
29.7
1.2
0.6
0.06
0.18 reprogram prom
0.22
0.04 npf; fuel trim
0.13 Replaced dist. cap/rotor/plug wire
0.30
0.05 light went out; npf; fuel trim
0.11 loose connection at PCM
0.10
0.08 Repair open wires at Coolant Sensor
0.03
0.32 R/R cam sensor $124 parts only
0.22
0.25 R/R O2 sensor
0.02
0.10 Replace PCM, wiring above trans broke
0.03
0.19 Replace EGR sensor
0.08
0.18 Reflashed PCM
0.05
0.16 Replace O2
0.25
0.07 Reflashed PCM
0.12
0.27 Replaced TPS
0.14
0.11 Replace Tr Input Sensor
0.05
0.1 1 Repair Wiring to O2 Sensor
0.10
0.34 new head
0.27
0.01 Replaced O2 sensor
0.03
0.06 Fix iat wiring
0.21
0.90 npf; fuel trim
0.11 R/R trans input sensor
0.03
0.13 R/R trans upper valve body assembly
0.16
0.17 leak at purge line
0.15 harmonic balancer bad
0.00 npf; fuel trim
0.21 R/R O2 sensor
0.17
0.10 repair tps wiring
0.02
0.04 O2 sensor
0.10
0.65 R/R O2 sensor
0.21
0.01 R/R plug wires 2&3 cylinders
0.03
0.19 replace egr back pressure transducer w/sol
0.05
0.12 replace combo valve for secondary air
0.02
0.08 dealer replaced speedsensor
0.07
0.20 light out; misfire
0.01 replaced plugs and installed
0.14 #2 plug wire
0.18 replace front o2 sens and therm ostadt
0.10
0.01 replace plugs and wires
0.05
0.15 replace plugs and wires
1
1
0.5
1.5
0.25
1.2
2.5
3
2
1.9
1.5
1.9
1.571429
1.285714
1.857143
7.142857
1
1
1
1.5
7.3
2.5
1
3.5
1
1
1
1
2
1.5
1.5
2
3
2.5
2.5
15
124
76
350
140
76
43
15
164
20
425
60
58
125
77
17
90
280
80
20
75
40
250
70
70
35
105
17.5
84
173
210
140
130
105
130
110
90
130
500
70
70
70
105
511
175
70
245
70
70
70
70
140
105
105
140
210
175
175
70
70
50
105
17.5
208
249
560
280
130
181
130
153
105
130
500
234
70
70
125
936
235
70
303
70
195
147
87
230
385
185
160
285
215
425
-------
EPA
EPA
EPA
EPA
EPA
EPA
EPA
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
14
17
18
23
26
28
29
3
6
7
15
18
20
21
25
26
28
29
31
32
34
37
38
4
23
28
29
33
34
36
38
39
41
42
45
46
47
97 DC
97 ford
96 mazda
96 ford
OGM
96 volks
97 ford
96 DC
96 ford
96 GM
96 FORD
96 Volvo
97 honda
96 GM
96 DC
97 honda
96 GM
96 DC
96 DC
96 GM
96 DC
96 GM
96 DC
98 Ford
98 Ford
98 GM
98 GM
98 GM
98 GM
98 DC
97 Ford
97 Ford
97 GM
98 GM
97 Ford
98 Ford
96 Ford
neon
escort
626
escort
century
jetta
escort
neon
crown viv
Corsica
continen
850
civic
cavalier
neon
camero
cirrus
sebring
regal
sebring
sl-2
neon
Windstar
Ranger
S10
Venture
Tahoe
Safari
Voyager
F150PU
E-250 Van
Suburban
Suburban
F150PU
Windstar
E-250 Van
2
2
2
1.8
3.4
2
2
2
4.6
3.1
4.6
2.4
1.6
2.2
2
2.7
5.7
2.4
2.5
3.8
1.9
3.8
3
4.3
3.4
5.7
4.3
3.3
4.6
4.2
5.7
5.7
4.6
3.8
4.9
final
41 449 initial
final
35965 initial
final
6061 5 initial
final
31 120 initial
final
48 initial
final
17016 initial
final
42038 initial
final
86236 initial
final
84848 initial
final
54048 initial
final
6251 7 initial
final
80355 initial
final
22359 initial
final
39483 initial
final
76168 initial
final
59734 initial
final
46607 initial
final
82626 initial
final
37620 initial
final
78027 initial
final
81 630 initial
final
55044 initial
final
40390 initial
final
20461 initial
final
1281 9 initial
final
181 12 initial
final
7634 initial
final
12577 initial
final
14187 initial
final
initial
final
29006 initial
final
44125 initial
final
2861 9 initial
final
18137 initial
final
19721 initial
final
25188 initial
final
51411 initial
0.163
0.1515
0.1515
0.087
0.0639
0.382
0.0956
0.346
0.305
0.1141
0.0797
0.1292
0.1292
0.0614
0.0599
1.743
0.224
2.444
0.204
0.483
0.293
0.319
0.321
0.197
0.123
0.175
0.18
0.146
0.146
0.134
0.125
0.194
0.169
0.123
0.164
0.231
0.225
0.328
0.244
0.394
0.189
0.205
0.188
0.392
0.14
0.628
0.208
0.073
0.073
0.993
0.165
0.305
0.204
0.2
0.2
0.305
0.284
0.166
0.166
0.053
0.064
0.282
0.131
0.127
0.127
0.22
0.22
0.21
0.201
0.145
0.144
0.081
0.084
0.18
0.13
0.14
0.14
0.07
0.06
0.33
0.08
0.31
0.27
0.09
0.07
0.12
0.12
0.06
0.06
0.07
0.07
0.82
0.13
0.26
0.18
0.18
0.18
0.26
0.25
0.15
0.15
0.05
0.06
0.19
0.11
0.11
0.11
0.18
0.18
0.15
0.14
0.12
0.13
0.07
0.07
0.10
1.7
1.0
1.0
1.2
0.8
6.9
1.0
4.3
4.4
0.6
0.6
1.4
1.4
0.9
0.8
52.0
2.1
39.5
4.8
8.7
2.5
4.8
4.4
1.5
1.0
1.8
2.4
2.1
2.4
1.6
1.2
1.3
1.0
1.5
2.0
6.3
6.3
4.1
1.6
2.7
2.4
2.1
1.0
3.2
1.5
5.0
2.2
0.7
0.7
21.3
1.8
2.6
1.8
3.4
3.4
2.4
2.2
1.6
1.6
0.4
0.5
7.5
1.9
2.1
2.1
2.0
2.3
2.4
2.6
1.6
2.3
1.1
1.0
1.2
0.17
0.19 303
0.19
0.29 402
0.15
1.01 171
0.22
0.20 302
0.16
0.09 122
0.07
0.09 303
0.09
0.14301
0.09
0.25
0.13
0.66 420, 301
0.47
0.36 301
0.83
0.27 304
0.18
4.39 410
0.28
0.20 302, 1300,
0.20
0.28 1406,440
0.22
0.69 403
0.39
0.29 302, 303, 1
0.32
0.76 172, 175,4
0.32
0.32 300, 303
0.33
0.39 134,133
0.34
0.45 304
0.43
0.45 134
0.37
0.50 300
0.51
0.34 121, 123
0.19
0.06 135, 155
0.06
0.18 1131
0.12
0.21 146
0.25
0.20 305
0.20
0.20 131, 134, 1
0.20
0.24 300
0.24
0.16 1698
0.21
0.29 141
0.14
0.26 503
0.26
0.35 102,131,1
0.31
0.66 161
0.45
0.76 304, 305, 3
0.10
0.20 302
0.16
0.62 133,1131
0.04
0.02
0.01
0.10
0.01
0.13
0.13
0.03
0.02
0.02
0.01
1.09
0.07
1.28
0.04
0.29
0.09
0.12
0.10
0.06
0.02
0.08
0.10
0.07
0.05
0.03
0.03
0.04
0.05
0.03
0.03
0.06
0.06
0.09
0.03
0.09
0.03
0.04
0.03
0.36
0.02
0.13
0.05
0.01
0.63
0.02
0.30
0.05
0.01
0.05
0.05
0.04
0.00
0.00
0.23
0.02
0.03
0.10
0.07
0.06
0.05
0.03
0.02
0.01
0.01
0.06
0.274
0.73
0.256
4.31
0.1177
2.95
2.55
0.0365
0.0496
0.24
0.203
36.4
0.5
29.1
3.6
9.3
1.3
4.0
2.7
0.8
0.2
1.5
3.3
1.6
1.4
0.5
0.2
0.2
0.4
0.1
0.3
2.3
2.3
2.4
0.1
1.3
0.7
0.1
0.1
3.0
0.2
1.3
0.7
0.1
11.8
0.18
2.19
0.43
0.03
0.26
0.2
0.07
0
0
3.7
0.4
1.4
0.7
0.4
0.2
0.14
0.3
0.12
0.21
0.07
-0.02
0.15 npf; misfire
0.41 R/R EGR vacuum sensor
0.21
0.89 replace catalyst
0.17
0.21 Replace air filter,plugs
0.22 wires and rotor
0.04 assembly error; wire clamped by hose clamp.
0.01
0.02 plugs cap
0.19 ignition wires
0.19 repair vacuum leak, no lite ever
0.19 replace downstream O2 sensor
0.88 replace coil and plugs,
0.48 clean air flow sensor
0.27 fuel rail replace ( sugar in gas )
0.93
0.22 recalibrate pcm
0.11
4.35 Replace the air pump
0.30
0.01 replace ECM
0.15
0.24 replace "W" valve
0.13
0.52 egr solenoid scan and replace
0.44
0.16 replace distributor cap
0.18
1 .01 replace canister, purge valve
0.41 & monitor
0.30 relace coil pack,plugs, and wires
0.29
0.52 scan .replace two o2 sensors
0.35 heat 122.85 downstream 99.45
0.36 $1 298 R/R rear cylinder head
0.32 $852 R/R front cylinder head
0.35 R/R O2 sensor
0.40
0.98 plugs and wires
0.45
0.40 r/r throttle body and reflash computer
0.20
0.04 npf; fuel trim
0.14 Replaced O2 sensor.
0.03
0.03 repaired three wires burned by exhaust
0.04 r/r rear O2 sensor reprogram computer
0.28 npf; misfire
0.20 Replace B1S1 O2 Sensor
0.24
0.24 npf; misfire
0.40 Replace Trans. Module
0.43
0.37 Replaced MAF
0.07
0.51 npf; vehicle speed sensor
0.18 two O2 sensors
0.25
0.72 O2 sensor
0.31
0.00 Water in fuel, replaced fuel pump
0.02
0.22 Bulletin No. 98-15-13
0.13
0.84 Replaced 2 B1S1 O2 sensors
2
2
5.5
2
1.5
1.3
1
3.2
4.8
6
0.9
2.1
2.5
3.2
1.2
0.5
5.1
2.9
2.4
1.8
2.5
2.828571
1
1.5
3
1
1.5
1
1.5
3.5
1
2
1.5
1.5
1
2.5
70
65
649
25
170
32
70
152
1088
406
350
219
90.83
15.48
115.78
224
222.3
100
51
275
70
70
70
100
240
140
70
105
100
150
140
140
242
140
105
90
70
224
336
420
66
145
175
215
84
32
357.5
202
134.4
104
170
198
70
105
210
70
105
70
105
245
70
140
105
105
70
175
210
205
667
165
105
260
102
292
488
1508
66
560
525
435
175
47.48
482.02
426
356.7
2150
204
221
473
70
175
280
70
175
70
205
485
70
280
175
210
170
325
-------
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
ATL
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
CDH
48
51
52
54
55
57
58
67
70
72
82
84
85
86
88
90
92
93
94
97
99
107
109
112
129
130
3
4
8
15
16
19
20
21
22
24
2
98 GM
96 DC
96 DC
97 Ford
97 Ford
97 Ford
97 FORD
97 DC
96 Ford
99 Ford
96 GM
99 ford
97 NISSAN
96 isuzu
97 DC
96 GM
97 Ford
99 Ford
97 Ford
96 GM
97 Nissan
99 DC
96 Ford
99 Nissan
96 gm
96 isuzu
98 GM
98 GM
96 toyota
98 DC
99 DC
96 DC
96 ford
98 DC
96 DC
97 ford
96 GM
Suburban
caravan
Caravan
F-150 Pick
F-150 Pick
Ranger
Villager
Caravan
E-150
Ranger
Tahoe
ranger
Quest
Rodeo
Ram Van
Cheyenne
F-150
Ranger
F150
Astro
Pickup
Caravan
F-150
Altima GXI
Astro
Hombre
jimmy
blazer
4-runner
cheroke
Caravan
Cherokee
explorer
CARAVAN
grand voya
ranger
blazer
5.7
3
3
4.2
5.4
2.3
3
3
4.9
3
5.7
3
3
3.2
3.9
5
4.2
3
4.6
4.3
2.4
3.3
5.8
2.4
4.3
2.2
4.3
4.3
3.4
4
3.3
4
4
3.3
3
4
4.3
final
19186 initial
final
65811 initial
final
73357 initial
final
64735 initial
final
76029 initial
final
19686 initial
final
8961 5 initial
final
87889 initial
final
77940 initial
final
8797 initial
final
58661 initial
final
11 974 initial
final
79540 initial
final
44157 initial
final
122781 initial
final
104689 initial
final
101 242 initial
final
7498 initial
final
29698 initial
final
91 737 initial
final
11 81 17 initial
final
22560 initial
final
89443 initial
final
13322 initial
final
175000 initial
final
245000 initial
final
8750 initial
final
61 56 initial
final
53052 initial
final
26959 initial
final
4439 initial
final
42253 initial
final
46706 initial
final
12241 initial
final
78642 initial
final
56239 initial
final
55439 initial
0.136
0.218
0.242
0.21
0.251
0.251
0.237
0.118
0.134
0.134
0.087
0.076
0.132
0.15
0.268
0.241
0.18
0.216
0.237
0.256
0.204
0.237
0.17
0.183
0.164
0.127
0.113
0.497
0.414
0.279
0.279
0.26
0.17
1.31
0.09
0.28
0.28
0.33
0.18
0.15
0.16
0.182
0.161
0.325
0.195
0.047
0.05
0.38
0.1
0.4
0.5
0.288
0.203
0.208
0.208
0.123
0.123
0.128
0.103
0.1176
0.1092
0.15
0.1299
0.1458
0.1082
0.1128
0.1128
0.226
0.1868
0.1332
0.1373
0.2
0.08
0.16
0.20
0.18
0.22
0.22
0.19
0.10
0.12
0.12
0.07
0.07
0.10
0.13
0.24
0.21
0.11
0.15
0.20
0.22
0.17
0.20
0.14
0.15
0.14
0.12
0.10
0.43
0.35
0.24
0.24
0.21
0.14
1.17
0.08
0.23
0.23
0.30
0.15
0.12
0.14
0.13
0.12
0.25
0.15
0.04
0.04
0.32
0.09
0.32
0.39
0.21
0.18
0.18
0.18
0.11
0.11
0.10
0.02
0.09
0.09
0.11
0.10
0.10
0.08
0.09
0.09
0.20
0.17
0.09
0.12
1.3
2.7
3.1
1.0
1.1
1.1
7.9
1.0
1.5
1.5
1.6
0.6
1.0
1.0
1.7
1.4
1.8
2.0
2.9
3.0
2.7
2.6
2.3
1.4
1.5
1.0
1.0
6.1
4.9
2.5
2.5
8.2
1.6
42.7
1.5
5.8
5.8
2.2
1.9
0.7
1.0
2.4
1.5
3.2
2.2
0.8
0.8
3.3
0.8
10.1
17.1
3.9
2.2
1.8
1.8
1.7
1.7
1.2
0.9
1.2
0.9
3.9
1.9
2.4
1.4
0.8
0.8
1.2
1.0
2.3
2.0
1.8
0.41
0.68 141
0.40
0.40 134
0.46 172
0.46
0.13 133,1131
0.10
0.17 174
0.17
0.11 171
0.14
0.40 136
0.51
0.36 133
0.34
0.65 174
0.61
0.62 1405
0.43
0.31 1406,112;
0.33
0.19351,352,3
0.33 733
0.37
0.30 502
0.34
1.16 305,138,1
1.07
0.27 1860,306
0.27
0.52
0.30
0.01 135, 155
0.02
0.21 172,175
0.21
0.66 102, 340
0.27
0.52 110
0.42
0.26 401
0.12
0.21 171, 174
0.56
0.09 141
0.04
0.97 420
0.17
1.36 108
0.57
2.14 605, 300, 1
0.26
0.25 306, 300
0.25
0.58 130, 133
0.58
0.11 303
0.09
0.26 401
0.98
0.25 138
0.22
0.23 153
0.13
0.22 1698
0.22
0.29 133
0.32
0.25 171, 174
0.12
0.56 1406
0.07
0.08
0.06
0.07
0.09
0.36
0.07
0.01
0.01
0.01
0.11
0.09
0.09
0. 1
0. 1
0. 8
0. 7
0. 0
0.08
0.06
0.10
0.06
0.01
0.02
0.29
0.38
0.25
0.08
1.11
0.01
0.03
0.16
0.08
0.09
0.06
0.08
0.05
0.07
0.07
0.00
0.00
0.28
0.02
0.40
0.33
0.04
0.05
0.06
0.01
0.04
0.01
0.04
0.03
0.05
0.05
0.04
0.04
0.02
0.06
0.04
0.04
0.01
0.06
0
0.11
0.2
0.14
0.54
18.6
0.0
0.1
0.11
0
0.9
0.42
0.65
0.24
0.15
2.18
1.78
1.18
0.89
0.2
2.32
0.41
0.2
0.17
4.79
5.2
21.0
0.9
53.0
0.0
0.3
1.3
1
1
0.6
0.73
0.25
0.62
0.52
0
0.1
2.9
0
11.8
14.7
0.0051
2.19
0.257
0.02
0.284
0.005
0.1431
0.0358
2.16
1.2
1.176
0.699
0.09
0.286
0.1897
1.621
0.753
0.658
0.51
0.61 Replaced B1S2 O2 Sensor
0.38
0.40 light out; fuel trim
0.53 npf; fuel trim
0.10 replace o2 sen
0.07
0.06 npf; fuel trim
0.18 replace o2 sen
0.15
0.42 replace o2 sen
0.52
0.33 replaced o2 sens
0.80 repair exhaust leak
0.65
0.83 npf; EGR
0.60
0.27 R/R EGR valve
0.18
0.08 light out; ignition system
0.38 TPS replaced
0.47
0.35 R/R speedo gear
0.38
1.28 new plugs
1.34
transmission wrong model year cost 1974 to replace
1 .04 R/R all four O2 sensors
0.41
0.01 Reconnect 2 front O2 sensors
0.02
0.27 npf; fuel trim
0.27 R/R O2 sensor, freed up EGR pintle
0.29
0.22 Replaced IAT and repaired wiring
0.37
0.11 Replace EGR valve
0.13
0.87 Replace EGR solenoid
1.05
0.05 Replace O2 B1S2
0.05
0.96 Replace cat and 2 O2 sensors
0.21
1 .33 R/R intake air temp sensor
0.86
2.08 dealer repair cpi-fuel inj. (fuel rail)
0.09
0.15 npf; misfire
0.61 light out; fuel trim
0.52 replace valve springs
0.41 clean combustion cxchamber
0.10 replace egr valve
0.04
0.20 replace O2 sensor
0.19
0.19 r/r left O2 sensor
0.08
0.20 light out; PCM communications
0.20 upstream O2 sensor
0.23
0.16 repl upper intake manifold &fuel rail gaskets
0.05
0.19 replace egr valve
2.5
1
1
1.5
1
1.5
1.5
1.5
1
1
2.6
1
1.5
1.5
1.5
4.2
1.5
1
2
2
1.3
1
2.5
3
1
5
1
1
5
2
1.5
2
1
2
6
1.6
76
70
70
70
70
117
37.52
20.73
12
232
83
45
142
23
76
466
16
450
55
91
105
72
70
40
185
173
70
105
70
105
105
105
70
70
182
105
105
105
0
294
105
70
140
140
87
70
173
210
70
350
0
350
140
105
140
140
420
109
249
70
70
175
70
175
175
175
70
70
299
70
142.52
125.73
117
1974
526
105
70
223
185
229
23
249
676
86
800
70
70
405
231
210
212
70
210
460
302
-------
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
CDH
4 96 GM
5 96 ford
8 96 ford
9 96 ford
10 96 DC
12 97 DC
14 96 ford
16 97 FORD
17 97 ford
19 96 ford
22 96 GM
23 97 ford
24 97 DC
27 96 GM
30 97 GM
33 97 DC
36 96 DC
39 96 ford
S10
f150
windstar
windstar
Voyager
gr cherokei
f150
F150
b4000(Maz
bronco
blazer
expedition
ram 1500
yukon
1500
ram 1500
caravan
bronco
4.9
3.8
3.8
3.3
4
5.8
4.6
4
5.8
4.3
5.4
5.9
5.7
5.7
5.9
5.8
final
27063 initial
final
30576 initial
final
44305 initial
final
68870 initial
final
57820 initial
final
26102 initial
final
107544 initial
final
86654 initial
final
24651 initial
final
3981 initial
final
100853 initial
final
49036 initial
final
67060 initial
final
71905 initial
final
45166 initial
final
11 3543 initial
final
80748 initial
final
109124 initial
final
0.196
0.41
0.196
0.169
.108
0.108
0.115
0.131
0.315
0.019
.193
0.193
0.228
0.221
0.194
0.17
0.152
0.137
0.319
0.176
0.469
0.37
0.123
0.105
3.76
0.255
0.26
0.281
0.229
0.235
0.546
0.159
0.366
0.131
1.9
4.0
2.2
2.0
1.1
1.1
1.2
1.4
4.9
0.4
1.2
1.2
2.6
2.8
3.3
2.8
2.5
1.9
6.5
2.1
5.8
4.2
2.7
1.2
10.7
4.2
2.8
3.1
2.9
2.9
12.8
2.3
6.8
2.3
0.41
108, 123,172,
0.51
0.35 171
0.39
0.36 402
0.36
0.96 174
0.83
1 .07 420
0.21
0.25 301
0.25
0.58 750
0.05
1.12 141
1.08
0.28 171, 174,7
0.26
0.41 133
0.48
0.55 147
0.55
0.51 156, 171, 1
0.42
0.89 201 , 753
0.59
0.56 1406
0.47
0.45 300,1870
0.46
2.88
0.23
1.67303
0.52
0.07
1441
0.29
0.08
0.06
0.03
0.03
0.05
0.15
0.10
0.08
0.06
0.06
0.57
0.05
0.03
0.30
0.04
0.04
0.24
0.16
0.01
0.01
10.97
0.10
0.09
0.10
0.08
0.07
0.31
0.06
0.14
0.03
0.618
5.22
1.256
0.265
0.68
1.6
1.8
4.2
1.2
0.3
0.4
0.6
1.5
0.8
2.4
0.7
0.1
0.4
3.2
2.0
0.1
0.1
32.1
3.7
0.8
0.6
1.3
1.0
9.1
0.9
5.2
0.8
0.09
install new pcm
0.57 ran two sulfur purge cycles
0.39 replace both hego's
0.38
0.22 light went out;npf; EGR
1 .33 sealed vacuum leak
1.09 (upper intake manifold)
1 .41 replaced the cat reflash PCM
0.17
0.28 light went out; npf; misfire
0.47 replace solenoid pack and pcm
0.43
1.37 R/R O2 sensor
1.23
0.07 r/r 2 O2 sensors and trans solenoid
0.21
0.32 R/R O2 sens
0.39
0.29 r/r O2 sen #2
0.32
0.38 replace 2 front hego sensors
0.31 rr cat efficicy monitor
1 .62 bare and brocken wires due to tampering
0.63
0.32 replace egr
0.46
0.49 r/r transmission valve body
0.40
3.00 R/R O2 semew cat
0.17
1.86 plugs and wires replace computer cat
0.49
failed state I/M passed lab no ftp
2.1
2
1
3.5
3
1
5.6
2.7
3
1.9
2.5
3.7
3.4
1.8
3.2
4.1
5.2
164
91
350
510
71
210
63
76
124
11.85
176
538
528
240
150
140
242
210
395
191
210
133
173
255.99
237
101
225
290
366
314
231
70
242
560
70
905
265
420
196
249
380
249.3
276
763
818
608
276.6993
------- |