sensor ISUZU AXIOM 2002 Service Repair Manual

6E±506
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Symptom Diagnosis
Preliminary Checks
Before using this section, perform the ªOn-Board
Diagnostic (OBD) System Checkº and verify all of the
following items:

The powertrain control module (PCM), and
malfunction indicator lamp (MIL) (Check Engine
lamp) and Reduced Power Lamp (RPL) are operating
correctly.

There are no DTC(s) stored.

Tech 2 data is within normal operating range. Refer to
Typical Scan Data Values.

Verify the customer complaint and locate the correct
symptom in the table of contents. Perform the
procedure included in the symptom chart.
Visual/Physical Check
Several of the symptom procedures call for a careful
visual/physical check. This can lead to correcting a
problem without further checks and can save valuable
time.
This check should include the following items:

PCM grounds for cleanliness, tightness and proper
location.

Vacuum hoses for splits, kinks, and proper
connections, as shown on the ªVehicle Emission
Control Informationº label. Check thoroughly for any
type of leak or restriction.

Air intake ducts for collapsed or damaged areas.

Air leaks at throttle body mounting area, mass air flow
(MAF) sensor and intake manifold sealing surfaces.

Ignition components for cracking, hardness, and
carbon tracking.

Wiring for proper connections, pinches and cuts.
Intermittents
IMPORTANT:An intermittent problem may or may not
turn on the malfunction indicator lamp (MIL) or store a
DTC. DO NOT use the Diagnostic Trouble Code (DTC)
charts for intermittent problems. The fault must be
present to locate the problem.
Most intermittent problems are caused by faulty electrical
connections or wiring. Perform a careful visual/physical
check for the following conditions:

Poor mating of the connector halves or a terminal not
fully seated in the connector (backed out).

Improperly formed or damaged terminal.

All connector terminals in the problem circuit should
be carefully checked for proper contact tension.

Poor terminal-to-wire connection. This requires
removing the terminal from the connector body to
check.
Road test the vehicle with a J 39200 Digital Multimeter
connected to a suspected circuit. An abnormal voltage
when the malfunction occurs is a good indication that
there is a fault in the circuit being monitored.
Use a Tech 2 to help detect intermittent conditions. The
scan tool has several features that can be used to locatean intermittent condition. Use the following feature to find
intermittent faults:

Using a Tech 2's ªFreeze Frameº buffer or ªFailure
Recordsº buffer can aid in locating an intermittent
condition. Review and record the information in the
freeze frame or failure record associated with the
intermittent DTC being diagnosed. The vehicle can
be driven within the conditions that were present
when the DTC originally set.
To check for loss of diagnostic code memory, disconnect
the MAP sensor and idle the engine until the MIL (Check
Engine lamp) comes on. DTC P0107 should be stored
and kept in memory when the ignition is turned ªOFFº. If
not, the PCM is faulty. When this test is completed, make
sure that you clear the DTC P0107 from memory.
An intermittent MIL (Check Engine lamp) with no stored
DTC may be caused by the following:

Ignition coil shorted to ground and arcing.

MIL (Check Engine lamp) wire to PCM shorted to
ground.

Poor PCM grounds. Refer to the PCM wiring
diagrams.
Check for improper installation of electrical options such
as lights, cellular phones, etc. Check all wires from the
PCM to the ignition coils for poor connections.
Check for an open diode across the A/C compressor
clutch and check for other open diodes (refer to wiring
diagrams in
Electrical Diagnosis).
If problem has not been found, refer to
PCM Connector
Symptom
tables.

Check the ªCalibration IDº of the PCM, and compare it
with the latest Isuzu service bulletins and/or Isuzu
EEPROM reprogramming equipment to determine if
an update to the PCM's reprogrammable memory
has been released. To check the ªCalibration IDº,
connect the Tech 2, then look for ªPowertrainº, then
select ªCalibration IDº. This identifies the contents of
the reprogrammable software and calibration
contained in the PCM. If the ªCalibration IDº is not the
most current available, it is advisable to reprogram
the PCM's EEPROM memory, which may either help
identify a hard-to-find problem or may fix the problem.

Calibration ID (example)
Part number 9377709
Broadcast Code CYYD
Identifier 801

6E±507
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Hard Start Symptom

StepActionValue(s)Ye sNo
1DEFINITION:
Engine cranks, but does not start for a long time. Does
eventually run, or may start but immediately stall.
Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Was the ªElectric Throttle Control (ETC) System
Checkº performed?
ÐGo to Step 3
Go to ETC
System
Check
31. 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?
ÐVerify repairGo to Step 4
4Was a visual/physical check performed?
ÐGo to Step 5
Go to Visual/
Physical
Check
5Check engine coolant temperature (ECT) sensor for
shift in value. After 8 hours with the hood up and the
engine not running, connect the Tech 2. With the
ignition ªONº and the engine not running, compare
engine coolant temperature to intake air temperature.
Are ECT and IAT within the specified value of each
other?
+ 5
C (+ 9
F)Go to Step 10Go to Step 6
61. Using a Tech 2, display the engine coolant
temperature and note the value.
2. Check the resistance of the engine coolant
temperature sensor.
3. Refer to
Engine Coolant Temperature Sensor
Temperature vs. Resistance
chart on DTC P0118
Diagnostic Support
for resistance specifications.
Is the resistance value near the resistance for the
temperature noted?
ÐGo to Step 8Go to Step 7
7Replace the ECT sensor.
Is the action complete?
ÐVerify repairÐ
8Locate and repair high resistance or poor connection in
the ECT signal circuit or the ECT sensor ground.
Is the action complete?
ÐVerify repairÐ
91. Check for a faulty, plugged, or incorrectly installed
PCV valve.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 10
101. Check for water- or alcohol-contaminated fuel.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 11
111. Perform the procedure in Fuel System Pressure
Test
.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 12

6E±509
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Surges and/or Chuggles Symptom

StepActionValue(s)Ye sNo
1DEFINITION:
Engine power variation under steady throttle or cruise.
Feels like the vehicle speeds up and slows down with
no change in the accelerator pedal.
Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Was the ªElectric Throttle Control (ETC) System
Checkº performed?
ÐGo to Step 3
Go to ETC
System
Check
31. 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?
ÐVerify repairGo to Step 4
4Was a visual/physical check performed?
ÐGo to Step 5
Go to Visual/
Physical
Check
5Be sure that the driver understands transmission
torque converter clutch and A/C compressor operation
as explained in the owner's manual.
Inform the customer how the TCC and the A/C clutch
operate.
Is the customer experiencing a normal condition?
ÐSystem OKGo to Step 6
61. Check the fuel control heated oxygen sensors
(HO2S, B1S1 and B2S1). The fuel control heated
oxygen sensors (HO2S) should respond quickly to
different throttle positions. If they don't, check them
for silicone or other contaminants from fuel or use of
improper RTV sealant. The sensors may have a
white powdery coating.
Silicon contamination causes a high but false
HO2S signal voltage (rich exhaust indication).
The PCM will then reduce the amount of fuel
delivered to the engine, causing a severe
driveability problem. For more information, refer
to
Powertrain Control Module (PCM) and Sensors.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 7
71. Check the fuel pressure. Refer to Fuel System
Pressure Test
.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 8
8Monitor the long term fuel trim on the Tech 2.
Is the long term fuel trim significantly in the negative
range (rich condition)?
ÐGo to Step 9Go to Step 10
91. Check items that can cause the engine to run rich.
Refer to
Diagnostic Aids in DTC P0172 Diagnostic
Support
.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐGo to Step 11Verify repair

6E±510
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Surges and/or Chuggles Symptom

 
StepNo Ye s Value(s) Action
101. Check items that can cause the engine to run lean.
Refer to
Diagnostic Aids in DTC P0171.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐGo to Step 11Verify repair
111. Check for proper ignition voltage output with spark
tester J 26792 (ST-125). Refer to
Electric Ignition
System
for procedure.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 12
121. Check for a loose ignition coil ground and ION
Sensing module circuit.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 13
131. Check the ignition coils for cracks or carbon
tracking.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 15
141. Remove the spark plugs and check for wet plugs,
cracks, wear, improper gap, burned electrodes, or
heavy deposits. Refer to
Electronic Ignition
System
.
NOTE: If spark plugs are gas or oil fouled, the cause of
the fouling must be determined before replacing the
spark plugs.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 15
151. Check the injector connections.
2. If any of the injector connectors are connected to an
incorrect cylinder, correct as necessary.
Was a problem found?
ÐVerify repairGo to Step 16
161. Check PCM grounds for the cleanliness, tightness
and proper locations. Refer to the PCM wiring
diagrams in
Electrical Diagnosis.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 17
171. Check MAF sensor connections.
2. If a problem is found, replace the faulty terminals as
necessary. Refer to
Electrical Diagnosis for wiring
repair procedures.
Was a problem found?
ÐVerify repairGo to Step 18
181. Visually/physically check vacuum hoses for splits,
kinks, and proper connections and routing as
shown on the ªVehicle Emission Control
Informationº label.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 19

6E±521
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Poor Fuel Economy Symptom

 
StepNo Ye s Value(s) Action
101. Check for an incorrect or faulty engine thermostat.
Refer to
Engine Cooling.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 11
111. Check for low engine compression. Refer to Engine
Mechanical
.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 12
121. Check the TCC operation. Refer to 4L30-E
Transmission Diagnosis
.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 13
131. 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 three-way
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?
ÐVerify repairGo to Step 14
14Check for proper calibration of the speedometer.
Does the speed indicated on the speedometer closely
match the vehicle speed displayed on the Tech 2?
ÐGo to Step 16Go to Step 15
15Diagnose and repair an inaccurate speedometer
condition as necessary. Refer to
Vehicle Speed
Sensor
in Electrical Diagnosis.
Was a problem found?
ÐVerify repairÐ
161. Check the air intake system and the crankcase for
air leaks. Refer to
Air Intake System and
Crankcase Ventilation System.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 17
171. Review all diagnostic procedures within this table.
2. When all procedures have been completed and no
malfunctions have been found, review/inspect the
following:

Visual/physical inspection

Tech 2 data

Freeze Frame data/Failure Records buffer

All connections within a suspected circuit
and/or system.
3. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 18
18Perform the procedure in Fuel System Pressure Test.
Was the fuel pressure normal?
Ð
Contact
Technical
Assistance
Verify repair

6E±525
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Backfire Symptom

StepActionValue(s)Ye sNo
1DEFINITION:
Fuel ignites in the intake manifold, or in the exhaust
system, making a loud popping noise.
Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo 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?
ÐVerify repairGo to Step 3
3Was a visual/physical check performed?
ÐGo to Step 4
Go to Visual/
Physical
Check
41. Check for proper ignition voltage coil output with
spark tester J 26792 (ST-125). Refer to
Electric
Ignition System
for procedure.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 5
51. Remove spark plugs and check for wet plugs,
cracks, wear, improper gap, burned electrodes, or
heavy deposits. Refer to
Electronic Ignition
System
.
NOTE: If spark plugs are gas or oil fouled, the cause of
the fouling must be determined before replacing the
spark plugs. Refer to
DTC P0172 to determine the
cause of a rich condition or
Engine Mechanical for an oil
fouling condition.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 6
61. Visually/physically inspect the ignition coils for
cracks.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 7
71. Check for an intermittent ignition system
malfunction:

Intermittent CKP 58X signal.

Intermittent ignition feed circuit or sensor
ground circuit to the crankshaft position
sensor.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 8
81. Check the fuel pressure. Refer to Fuel System
Pressure Test
.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 9

6E±530
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Hesitation, Sag, Stumble Symptom

StepActionValue(s)Ye sNo
1DEFINITION:
Momentary lack of response as the accelerator is
pushed down. Can occur at any vehicle speed. Usually
most pronounced when first trying to make the vehicle
move, as from a stop sign. May cause the engine to stall
if severe enough.
Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Was the ªElectric Throttle Control (ETC) System
Checkº performed?
ÐGo to Step 3
Go to ETC
System
Check
31. 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?
ÐVerify repairGo to Step 4
4Was a visual/physical check performed?
ÐGo to Step 5
Go to Visual/
Physical
Check
51. Check the fuel control heated oxygen sensors
(HO2S, B1S1 and B2S1). The fuel control heated
oxygen sensors (HO2S) should respond quickly to
different throttle positions. If they don't, check them
for silicon or other contaminants from fuel or use of
improper RTV sealant. The sensors may have a
white powdery coating.
Silicon contamination causes a high but false
HO2S signal voltage (rich exhaust indication).
The PCM will then reduce the amount of fuel
delivered to the engine, causing a severe
driveability problem. For more information, refer
to
Powertrain Control Module (PCM) and Sensors.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 6
61. Check the fuel pressure. Refer to Fuel System
Pressure Test.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 7
7Observe the TP 1, 2 angle display on the Tech 2 while
slowly increasing accelerator pedal depression.
Does the TP angle display steadily increase from 8 ~
10% at closed throttle to 90 ~ 92% at WOT?
ÐGo to Step 8Go to Step 9
8Monitor the long term fuel trim on the Tech 2.
Is the long term fuel trim significantly in the negative
range (rich condition)?
ÐGo to Step 9Go to Step 10
91. Check items that can cause the engine to run rich.
Refer to
Diagnostic Aids in DTC P0172 Diagnostic
Support
.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 11

6E±531
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Hesitation, Sag, Stumble Symptom

 
StepNo Ye s Value(s) Action
101. Check items that can cause the engine to run lean.
Refer to
Diagnostic Aids in DTC P0171 Diagnostic
Support
.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 11
111. Check for proper ignition voltage output with spark
tester J 26792 (ST-125). Refer to
Electronic Ignition
System
for the procedure.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 12
121. Check for a loose ignition coil ground and ION
Sensing module circuit.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 13
131. Check the ignition coils for cracks or carbon
tracking.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 14
141. Remove spark plugs and check for wet plugs,
cracks, wear, improper gap, burned electrodes, or
heavy deposits. Refer to
Electronic Ignition
System
.
NOTE: If spark plugs are gas or oil fouled, the cause of
the fouling must be determined before replacing the
spark plugs.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 15
151. Check the PCM grounds for clearness, tightness
and proper routing. Refer to the PCM wiring
diagrams in Electrical Diagnosis.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 16
161. Check the MAF sensor connections.
2. If a problem is found, replace the faulty terminals as
necessary. Refer to
Electrical Diagnosis for wiring
repair procedures.
Was a problem found?
ÐVerify repairGo to Step 17

6E±533
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Bank 1 Restricted Exhaust System Check

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Remove the Bank 1 HO2S 2.
2. Install the Exhaust Backpressure Tester
(BT-8515-V or equivalent) in place of the Bank 1
HO2S 2.
3. Run the engine at normal operating temperature.
4. Increase the engine speed to 2000 RPM and allow
10 seconds for pressure to build.
5. Observe the exhaust system backpressure reading
on the gauge.
Does the reading exceed the amount in the value
column?
8.62 kPa
(1.25 psi)
Go to Step 3Go to Step 4
3Repair the restriction in the exhaust system after the
catalytic converter.
Possible faults include:

Collapsed pipe

Heat distress

Internal muffler failure
Is the action complete?
ÐVerify repairÐ
41. Install the Bank 1 HO2S 2.
2. Install the Exhaust Backpressure Tester in place of
Bank 1 HO2S 1.
3. Run the engine at normal operating temperature.
4. Increase the engine speed to 2000 RPM and allow
10 seconds for pressure to build.
5. Observe the exhaust system backpressure reading
on the gauge.
Does the reading exceed the amount in the value
column?
8.62 kPa
(1.25 psi)
Go to Step 5
No trouble
found. If a
driveability
symptom
exists, refer
to symptom
charts
5Repair the restriction in the catalytic converter.
Is the action complete?
ÐVerify repairÐ
NOTE: DTCs will be set by running the vehicle to normal
operating temperature after a cold start with the O2
sensor disconnected. After performing these tests, use
the Tech 2 to erase the DTCs that were set by the lack of
O2 sensor activity.

6E±534
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Bank 2 Restricted Exhaust System Check

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Remove the Bank 2 HO2S 2.
2. Install the Exhaust Backpressure Tester
(BT-8515-V or equivalent) in place of the Bank 2
HO2S 2.
3. Run the engine at normal operating temperature.
4. Increase the engine speed to 2000 RPM and allow
10 seconds for pressure to build.
5. Observe the exhaust system backpressure reading
on the gauge.
Does the reading exceed the amount in the value
column?
8.62 kPa
(1.25 psi)
Go to Step 3Go to Step 4
3Repair the restriction in the exhaust system after the
catalytic converter.
Possible faults include:

Collapsed pipe

Heat distress

Internal muffler failure
Is the action complete?
ÐVerify repairÐ
41. Install the Bank 2 HO2S 2.
2. Install the Exhaust Back pressure Tester in place of
Bank 1 HO2S 1.
3. Run the engine at normal operating temperature.
4. Increase the engine speed to 2000 RPM and allow
10 seconds for pressure to build.
5. Observe the exhaust system backpressure reading
on the gauge.
Does the reading exceed the amount in the value
column?
8.62 kPa
(1.25 psi)
Go to Step 5
No trouble
found. If a
driveability
symptom
exists, refer
to symptom
charts
5Repair the restriction in the catalytic converter.
Is the action complete?
ÐVerify repairÐ
NOTE: DTCs will be set by running the vehicle to normal
operating temperature after a cold start with the O2
sensor disconnected. After performing these tests, use
the Tech 2 to erase the DTCs that were set by the lack of
O2 sensor activity.