service OPEL FRONTERA 1998 Workshop Manual

6E–24
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnosis
Strategy-Based Diagnostics
Strategy-Based Diagnostics
The strategy-based diagnostic is a uniform approach to
repair all Electrical/Electronic (E/E) systems. The
diagnostic flow can always be used to resolve an E/E
system problem and is a starting point when repairs are
necessary. The following steps will instruct the technician
how to proceed with a diagnosis:
1. Verify the customer complaint.
To verify the customer complaint, the technician
should know the normal operation of the system.
2. Perform preliminary checks.
Conduct a thorough visual inspection.
Review the service history.
Detect unusual sounds or odors.
Gather diagnostic trouble code information to
achieve an effective repair.
3. Check bulletins and other service information.
This includes videos, newsletters, etc.
4. Refer to service information (manual) system
check(s).
“System checks” contain information on a system
that may not be supported by one or more DTCs.
System checks verify proper operation of the
system. This will lead the technician in an
organized approach to diagnostics.
5. Refer to service diagnostics.
DTC Stored
Follow the designated DTC chart exactly to make an
effective repair.
No DTC
Select the symptom from the symptom tables. Follow the
diagnostic paths or suggestions to complete the repair.
You may refer to the applicable component/system check
in the system checks.
No Matching Symptom
1. Analyze the complaint.
2. Develop a plan for diagnostics.
3. Utilize the wiring diagrams and the theory of
operation.
Call technical assistance for similar cases where repair
history may be available. Combine technician knowledge
with efficient use of the available service information.
Intermittents
Conditions that are not always present are called
intermittents. To resolve intermittents, perform the
following steps:
1. Observe history DTCs, DTC modes, and freezeframe
data.2. Evaluate the symptoms and the conditions described
by the customer.
3. Use a check sheet or other method to identify the
circuit or electrical system component.
4. Follow the suggestions for intermittent diagnosis
found in the service documentation.
Most scan tools, such as the Tech 2 and the DVM, have
data-capturing capabilities that can assist in detecting
intermittents.
No Trouble Found
This condition exists when the vehicle is found to operate
normally. The condition described by the customer may
be normal. Verify the customer complaint against another
vehicle that is operating normally. The condition may be
intermittent. Verify the complaint under the conditions
described by the customer before releasing the vehicle.
1. Re-examine the complaint.
When the complaint cannot be successfully found or
isolated, a re-evaluation is necessary. The complaint
should be re-verified and could be intermittent as
defined in
Intermittents, or could be normal.
2. Repair and verify.
After isolating the cause, the repairs should be made.
Validate for proper operation and verify that the
symptom has been corrected. This may involve road
testing or other methods to verify that the complaint
has been resolved under the following conditions:
Conditions noted by the customer.
If a DTC was diagnosed, verify a repair by
duplicating conditions present when the DTC was
set as noted in the Failure Records or Freeze
Frame data.
Verifying Vehicle Repair
Verification of the vehicle repair will be more
comprehensive for vehicles with OBD system
diagnostics. Following a repair, the technician should
perform the following steps:
IMPORTANT:Follow the steps below when you verify
repairs on OBD systems. Failure to follow these steps
could result in unnecessary repairs.
1. Review and record the Failure Records and the
Freeze Frame data for the DTC which has been
diagnosed (Freeze Frame data will only be stored for
the MIL (“Check Engine” lamp) has been requested).
2. Clear the DTC(s).
3. Operate the vehicle within conditions noted in the
Failure Records and Freeze Frame data.
4. Monitor the DTC status information for the specific
DTC which has been diagnosed until the diagnostic
test associated with that DTC runs.

6E–25 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
General Service Information
Serviceability Issues
Non-OEM Parts
All of the OBD diagnostics have been calibrated to run
with OEM parts. Accordingly, if commercially sold sensor
or switch is installed, it makes a wrong diagnosis and turn
on the MIL (“Check Engine” lamp).
Aftermarket electronics, such as cellular phones,
stereos, and anti-theft devices, may radiate EMI into the
control system if they are improperly installed. This may
cause a false sensor reading and turn on the MIL (“Check
Engine” lamp).
Poor Vehicle Maintenance
The sensitivity of OBD diagnostics will cause the MIL
(“Check Engine” lamp) to turn on if the vehicle is not
maintained properly. Restricted oil filters, fuel filters, and
crankcase deposits due to lack of oil changes or improper
oil viscosity can trigger actual vehicle faults that were not
previously monitored prior to OBD. Poor vehicle
maintenance can not be classified as a “non-vehicle
fault”, but with the sensitivity of OBD diagnostics, vehicle
maintenance schedules must be more closely followed.
Related System Faults
Many of the OBD system diagnostics will not run if the
ECM detects a fault on a related system or component.
Visual/Physical Engine Compartment
Inspection
Perform a careful visual and physical engine
compartment inspection when performing any diagnostic
procedure or diagnosing the cause of an emission test
failure. This can often lead to repairing a problem without
further steps. Use the following guidelines when
performing a visual/physical inspection:
Inspect all vacuum hoses for punches, cuts,
disconnects, and correct routing.
Inspect hoses that are difficult to see behind other
components.
Inspect all wires in the engine compartment for proper
connections, burned or chafed spots, pinched wires,
contact with sharp edges or contact with hot exhaust
manifolds or pipes.
Basic Knowledge of Tools Required
NOTE: Lack of basic knowledge of this powertrain when
performing diagnostic procedures could result in an
incorrect diagnosis or damage to powertrain
components. Do not attempt to diagnose a powertrain
problem without this basic knowledge.
A basic understanding of hand tools is necessary to effec-
tively use this section of the Service Manual.
Serial Data Communications
Class II Serial Data Communications
This vehicle utilizes the “Class II” communication system.
Each bit of information can have one of two lengths: longor short. This allows vehicle wiring to be reduced by
transmitting and receiving multiple signals over a single
wire. The messages carried on Class II data streams are
also prioritized. If two messages attempt to establish
communications on the data line at the same time, only
the message with higher priority will continue. The device
with the lower priority message must wait.
On this vehicle the Tech 2 displays the actual values for
vehicle parameters. It will not be necessary to perform
any conversions from coded values to actual values.
On-Board Diagnostic (OBD)
On-Board Diagnostic Tests
A diagnostic test is a series of steps, the result of which is
a pass or fail reported to the diagnostic executive. When
a diagnostic test reports a pass result, the diagnostic
executive records the following data:
The diagnostic test has been completed since the last
ignition cycle.
The diagnostic test has passed during the current
ignition cycle.
The fault identified by the diagnostic test is not
currently active.
When a diagnostic test reports a fail result, the diagnostic
executive records the following data:
The diagnostic test has been completed since the last
ignition cycle.
The fault identified by the diagnostic test is currently
active.
The fault has been active during this ignition cycle.
The operating conditions at the time of the failure.
Comprehensive Component Monitor
Diagnostic Operation
Comprehensive component monitoring diagnostics are
required to operate engine properly.
Input Components:
Input components are monitored for circuit continuity and
out-of-range values. This includes rationality checking.
Rationality checking refers to indicating a fault when the
signal from a sensor does not seem reasonable. Accel
Position (AP) sensor that indicates high throttle position
at low engine loads or MAP voltage. Input components
may include, but are not limited to the following sensors:
Intake Air Temperature (IAT) Sensor
Crankshaft Position (CKP) Sensor
Intake throttle Position (ITP) Sensor
Engine Coolant Temperature (ECT) Sensor
Camshaft Position (CMP) Sensor
Manifold absolute Pressure (MAP) Sensor
Accel Position Sensor
Fuel Temp Sensor
Rail Pressure Sensor
Oil Temp Sensor
EGR Pressure Sensor
Vehicle Speed Sensor

6E–28
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
in the ECM’s memory, the DTC(s) will be output from the
lowest to the highest, with each DTC being displayed
three times.
The DTC display will continue as long as the DLC is
shorted.
Reading Diagnostic Trouble Codes Using
a TECH 2
The procedure for reading diagnostic trouble code(s) is to
used a diagnostic Tech 2. When reading DTC(s), follow
instructions supplied by Tech 2 manufacturer.
For the 1998 model year, Isuzu dealer service
departments will continue to use Tech 2.
Clearing Diagnostic Trouble Codes
IMPORTANT:Do not clear DTCs unless directed to do
so by the service information provided for each diagnostic
procedure. When DTCs are cleared, the Freeze Frame
and Failure Record data which may help diagnose an
intermittent fault will also be erased from memory.
If the fault that caused the DTC to be stored into memory
has been corrected, the Diagnostic Executive will begin to
count the “warm-up” cycles with no further faults
detected, the DTC will automatically be cleared from the
ECM memory.To clear Diagnostic Trouble Codes (DTCs), use the Tech
2 “clear DTCs” or “clear information” function. When
clearing DTCs follow instructions supplied by the Tech 2
manufacturer.
When a Tech 2 is not available, DTCs can also be cleared
by disconnecting
one of the following sources for at least
thirty (30) seconds.
NOTE: To prevent system damage, the ignition key must
be “OFF” when disconnecting or reconnecting battery
power.
The power source to the control module. Examples:
fuse, pigtail at battery ECM connectors etc.
The negative battery cable. (Disconnecting the
negative battery cable will result in the loss of other
on-board memory data, such as preset radio tuning).
060RW169

6E–29 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Tech 2 Scan Tool
From 98 MY, Isuzu dealer service departments are
recommended to use Tech 2. Please refer to Tech 2 user
guide.
901RW257
Legend
(1) PCMCIA Card
(2) SAE 16/19 Adaptor(3) DLC Cable
(4) Tech–2

6E–32
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
DTC Modes
There are three options available in the Tech 2 DTC mode
to display the enhanced information available. A
description of the new modes, DTC Info, follows. After
selecting DTC, the following menu appears:
DTC Info
Clear Info
Read DTC Info Ordered By Priority
The following is a brief description of each of the sub
menus in DTC Info. The order in which they appear here is
alphabetical and not necessarily the way they will appear
on the Tech 2.
DTC Information Mode
Use the DTC info mode to search for a specific type of
stored DTC information.The service manual may instruct
the technician to test for DTCs in a certain manner.
Always follow published service procedures.
Fail This Ignition
This selection will display all DTCs that have failed during
the present ignition cycle.
History
This selection will display only D T C s t h a t a r e s t o r e d i n t h e
ECM’s history memory. It will not display Type B DTCs
that have not requested the MIL (“Check Engine” lamp). It
will display all type A and B DTCs that have requested the
MIL and have failed within the last 40 warm-up cycles. In
addition, it will display all type C and type D DTCs that
have failed within the last 40 warm-up cycles.
MIL SVC or Message Requested
This selection will display only DTCs that are requesting
the MIL. Type C and type D DTCs cannot be displayed
using this option. This selection will report type B DTCs
only after the MIL has been requested.
Test Failed Since Code Cleared
This selection will display all active and history DTCs that
have reported a test failure since the last time DTCs were
cleared.
Injector Test
This test is conducted to make it sure that appropriate
electric signals are being sent to injectors Nos. 1 – 4.
Tech–2 must be used for this test.
Test Procedure:
1. Connect Tech–2 to the vehicle DLC.
2. Set Ignition Switch to the “ON” position.
3. Select Control Test.
4. Select Injector Test.
5. Send instructions to each injector(Switch on), making
sure of injector working noise.
NOTE: If injector working noise (Clink) can hardly be
confirmed, remove the engine head cover noise
insulation.
Refer to Section 6A.6. In the injector whose working noise has been
confirmed, its electric circuit can be regarded as
normal.
As for the injector whose working noise has not been
confirmed, its electric circuit or the injector proper is
faulty.
EGR Valve Test
This test is conducted to check EGR valve for its working.
This test needs Tech–2.
Test Procedure
1. Connect Tech–2 to vehicle DLC.
2. Switch on the engine.
3. Select “DIAGNOSIS” from the main menu.
4. Select Miscellaneous Test.
5. Select EGR Valve.
6. Instruct EGR Valve to check a data list.
7. If change in the data list shows a normal valve, the
working of EGR Valve can be judged to be normal.
Rail Pressure Control Valve Test
This test is conducted to check RPC valve for its working.
This test needs Tech–2.
Test Procedure
1. Connect Tech–2 to vehicle DLC.
2. Switch on the engine.
3. Select “DIAGNOSIS” from the main menu.
4. Select Miscellaneous Test.
5. Select Rail Pressure Control Valve.
6. Instruct RPC Valve to check a data list.
7. If change in the data list shows a normal valve, the
working of RPC Valve can be judged to be normal.
Injector Balance Test
This test is conducted to make it sure that appropriate
electric signals are being sent to injectors Nos. 1-4, when
the engine is idling.
This test needs Tech–2.
Test Procedure
1. Connect Tech–2 to vehicle DLC.
2. The engine is running at idling condition.
3. Select “DIAGNOSIS” from the main menu.
4. Select Miscellaneous Test.
5. Select the injector Balance Test.
6. Send instructions to each injector(Switch On),
making sure change of the engine vibration.
7. In the injector whose change of the vibration has been
confirmed, it’s electric circuit can be regarded as
normal.
Data Programming in Case of ECM Change
When replacing ECM, it is necessary to confirm and
record the group sign of injector beforehand. For this
confirmation.

6E–41 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
EGR (Exhaust Gas Recirculation)
Diagnosis
A diagnosis of the EGR system is covered by DTC
P1403.
EGR VSV circuit diagnosis is covered by DTC P1404.
EGR pressure sensor diagnosis is covered by DTC
P405 and/or P406.
EGR EVRV circuit diagnosis is covered by DTC
P1405. Refer to the DTC charts.
Tech 2 Data Definitions and Ranges
A/C CLUTCH–Tech 2 Displays ON or OFF–
Indicates whether the A/C has commanded the A/C
clutch ON.
MAP kPa — Tech 2 Range 10-105 kPa/0.00-5.00
Vo l t s —
The manifold absolute pressure reading is determined
from the MAP sensor signal monitored during key up and
wide open throttle (WOT) conditions. The manifold
absolute pressure is used to compensate for altitude
differences and is normally displayed around “61-104”
depending on altitude and manifold absolute pressure.
CMP ACT. COUNTER –Cam Position
DESIRED IDLE — Tech 2 Range 0-3187 RPM —
The idle speed that the ECM is commanding. The ECM
will compensate for various engine loads based on engine
coolant temperature, to keep the engine at the desired
speed.
ECT — (Engine Coolant Temperature) Tech 2
Range –40
C to 151C (–40F to 304F) —
The engine coolant temperature (ECT) is mounted in the
coolant stream and sends engine temperature
information to the ECM. The ECM applies 5 volts to the
ECT sensor circuit. The sensor is a thermistor which
changes internal resistance as temperature changes.
When the sensor is cold (high resistance), the ECM
monitors a high signal voltage and interprets that as a cold
engine. As the sensor warms (decreasing resistance),
the voltage signal will decrease and the ECM will interpret
the lower voltage as a warm engine.
ENGINE RUN TIME — Tech 2 Range
00:00:00-99:99:99 Hrs:Min:Sec —
Indicates the time elapsed since the engine was started.
If the engine is stopped, engine run time will be reset to
00:00:00.
ENGINE SPEED — Range 0-9999 RPM —
Engine speed is computed by the ECM from the 57X
reference input. It should remain close to desired idle
under various engine loads with engine idling.Air Intake Valve meter POSITION — Tech 2 Range
0-100 % —
IAT (INTAKE AIR TEMPERATURE)— Tech 2 Range
–40
C to 151C (–40F to 304F) —
The ECM converts the resistance of the intake air
temperature sensor to degrees. Intake air temperature
(IAT) is used by the ECM to adjust fuel delivery and spark
timing according to incoming air density.
MAP — Tech 2 Range 10-105 kPa (0.00-4.97 Volts)—
The manifold absolute pressure (MAP) sensor measures
the change in the boost pressure.
MIL — Tech 2 Displays ON or OFF —
Indicates the ECM commanded state of the malfunction
indicator lamp.
AP — Tech 2 Range 0%-100% —
AP (Accelerator position) angle is computed by the ECM
from the AP sensor voltage. AP angle should display
“0%” at idle and “100%” at wide open throttle.
AP SENSOR — Tech 2 Range 0.00-5.00 Volts —
The voltage being monitored by the ECM on the AP
sensor signal circuit.
VEHICLE SPEED—Tech 2 Range 0-255 km/h (0-155
mph)–
The vehicle speed sensor signal is converted into km/h
and mph for display.
Typical Scan Data Values
Use the Typical Scan Data Values Table only after the
On-Board Diagnostic System Check has been
completed, no DTC(s) were noted, and you have
determined that the on-board diagnostics are functioning
properly. Tech 2 values from a properly-running engine
may be used for comparison with the engine you are
diagnosing. The typical scan data values represent
values that would be seen on a normally-running engine.
NOTE: A Tech 2 that displays faulty data should not be
used, and the problem should be reported to the Tech 2
manufacturer. Use of a faulty Tech 2 can result in
misdiagnosis and unnecessary replacement of parts.
Only the parameters listed below are referred to in this
service manual for use in diagnosis. For further
information on using the Tech 2 to diagnose the ECM and
related sensors, refer to the applicable reference section
listed below. If all values are within the typical range
described below, refer to the
Symptoms section for
diagnosis.
Test Conditions
Engine running, lower radiator hose hot, transmission in
park or neutral, accessaries off, brake not applied and air
conditioning off.

6E–48
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Malfunction Indicator Lamp (MIL) “ON” Steady
StepActionVa l u e ( s )Ye sNo
1Was the “On-Board diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Ignition “OFF,” disconnect ECM.
2. Ignition “ON,” observe the MIL (CHECK ENGINE
lamp).
Is the MIL “ON?”
—Go to Step 3Go to Step 5
31. Ignition “OFF,” disconnect the instrument panel
cluster.
2. Check the MIL driver circuit between the ECM and
the instrument panel cluster for a short to ground.
3. If a problem is found, repair as necessary.
Was the MIL driver circuit shorted to ground?
—
Go to OBD
System
Check
Go to Step 4
4Replace the instrument panel cluster.
Is the action complete?
—
Go to OBD
System
Check
—
51. Ignition “OFF,” reconnect the ECM.
2. Ignition “ON,” reprogram the ECM. Refer to
On-Vehicle Service in Engine Control Module and
Sensor
for procedures.
3. Using the Tech 2 output controls function, select
MIL dash lamp control and command the MIL
“OFF.”
Did the MIL turn “OFF?”
—
Go to OBD
System
Check
Go to Step 6
6Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
—
Go to OBD
System
Check
—

6E–130
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1403 (Flash DTC 32)
EGR EVRV Fault
060RW135
Circuit Description
EGR EVRV Circuit has a common power source in
parallel with EGR, VSV, RPCV, and Intake Throttle Motor.
This may cause multiple DTCs. On such occasion, refer
to “Multiple ECM Information sensor DTCs Set”.
Diagnostic Aids
Check for the following conditions:
Poor connection or damaged EVRV – Inspect the
wiring harness for damage.
Ensure EVRV is correctly mounted. See On-Vehicle
Service.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart
3. A malfunctioning MAP sensor can set an EGR DTC.
The MAP sensor could send a constant signal which
is not low enough to set a low MAP DTC. The
constant signal from the MAP sensor also may not
be high enough to set a high MAP DTC. This step
verifies that the MAP sensor is responding.

6E–181 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Lack of Power, Sluggish or Spongy Symptom
StepActionVa l u e ( s )Ye sNo
1DEFINITION:
Engine delivers less than expected power. Little or no
increase in speed when accelerator pedal is pushed
down part-way.
Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
—Verify repairGo to Step 3
3Was a visual/physical check performed?
—Go to Step 4
Go to Visual/
Physical
Check
41. Remove and check the air filter element for dirt or
restrictions. Refer to
Air Intake System in
On-Vehicle Service.
2. Replace the air filter element if necessary.
Was a repair required?
—Verify repairGo to Step 5
51. Check AP sensor system. Refer to AP sensor
diagnostic
.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 6
61. Check for water-or alcohol-contaminated fuel.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 7
71. Using a Tech 2, Injector test.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 8
81. Check the ECM grounds for the cleanliness,
tightness and proper locations. Refer to the ECM
wiring diagrams in
Electrical Diagnosis.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 9
91. Check the exhaust system for possible restriction:
Inspect the exhaust system for damaged or
collapsed pipes.
Inspect the muffler for heat distress or possible
internal failure.
Check for a possible plugged catalytic
converter by checking the exhaust system
back pressure. Refer to
Restricted Exhaust
System Check
.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 10
101. Check the torque converter clutch (TCC) for proper
operation. Refer to
Transmission Diagnosis.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 11

6E–199 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Default Matrix Table
Service Procedure Default Strategy
A referral strategy has been established to assist the
technician with additional information when the cause ofthe failure cannot be determined. If no problem is found
after performing diagnostics, then refer to the default
matrix table for further diagnostic information.
Default Matrix Table
Strategy Based Diagnostic ChartsInitial DiagnosisDefault Section(s)
On-Board Diagnostic (OBD) System
CheckVehicle does not enter diagnostics.Chassis Electrical
On-Board Diagnostic (OBD) System
CheckVehicle enters diagnostics and
communicates with the Tech 2. MIL is
“ON” in diagnostics. Engine does not
start and run.HEUI System Check
On-Board Diagnostic (OBD) System
CheckEngine starts and runs, no ECM codes
set. Customer complains of vibration.—
On-Board Diagnostic (OBD) System
CheckEngine starts and runs, no ECM codes
set. Customer complains of harsh or
soft shift, poor performance, delayed or
no engagement into drive or reverse,
transmission fluid leak, transmission
noise or vibration, or improper TCC
operation.Automatic Transmission
ECM Power and Ground CheckOn-Board Diagnostic (OBD) System
Check.Chassis Electrical
ECM Power and Ground CheckOn-Board Diagnostic (OBD) System
Check. ECM power and ground circuits
OK. Data link voltage incorrect.Chassis Electrical
On-Board Diagnostic (OBD) System
CheckEngine starts and runs, no ECM codes
set. Customer complains of harsh or
soft shift, poor performance, delayed or
no engagement into drive or reverse,
transmission fluid leak, transmission
noise or vibration, or improper TCC
operation.Automatic Transmission
SymptomsInitial DiagnosisDefault Section(s)
Intermittents1. On-board diagnostic (OBD)
system check.
2. Careful visual/physical inspections.Chassis Electrical
Hard Starts1. OBD system check.
2. Sensors (ECT, MAP, EGR, AP) ;
output chart.
3. Fuel system electrical test, fuel
system diagnosis.
4. Injector system.Engine Mechanical, Injector
System Check, Exhaust System
Diagnosis
Surges and/or Chuggles1. OBD system check.
2. Fuel system diagnosis.
3. Injector system.Calibration ID “Broadcast”
/Service Bulletins, Ignition
System Check, Generator
Output, Exhaust System
Diagnosis
Lack of Power, Sluggish or Spongy1. OBD system check.
2. Fuel system diagnosis.
3. Injector system.Refer to Exhaust System in
Engine Exhaust, TCC
Operation, Calibration
ID/Service Bulletins