2002 ISUZU AXIOM ignition

6E±196
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0151 ± HO2S Circuit Low Voltage Bank 2 Sensor 1

 
StepNo Ye s Value(s) Action
81. Ignition ªOFFº.
2. Reconnect the PCM, leave HO2S disconnected.
3. Ignition ªONº.
Does the Tech 2 indicate Bank 2 HO2S 1 voltage near
the specified value?
425-475 mV
Refer to
Diagnostic
Aids
Go to Step 9
9Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
On-Vehicle Service in
Powertrain Control Module and Sensors for
procedures.
And also refer to latest Service Bulletin.
Check to see if the Latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.
Is the action complete?
ÐVerify repairÐ

6E±198
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
check EVAP control system components and hoses.
Refer to Evaporative Emission (EVAP) Control
System.

MAF sensor ± The system can go rich if the MAF
sensor signal indicates an engine airflow
measurement that is not correct. Disconnect the MAF
sensor to see if rich condition is corrected. If so,
replace MAF sensor.

Check for leaking fuel pressure regulator diaphragm by
checking vacuum line to regulator for the presence of
fuel. There should be no fuel in the vacuum line.

TP sensor ± An intermittent TP sensor output will
cause the system to go rich, due to a false indication
of the engine accelerating.

Shorted Heated Oxygen Sensor (HO2S)± If the HO2S
is internally shorted, the HO2S voltage displayed on
the Tech 2 will be over 1 volt. Try disconnecting the
affected HO2S with the key ªONº, engine ªOFFº. If the
displayed HO2S voltage changes from over 1000 mV
to around 450 mV, replace the HO2S. Silicon
contamination of the HO2S can cause a high HO2S
voltage to be indicated. This condition is indicated by
powdery deposit on the portion of the HO2S exposed
to the exhaust stream. If contamination is noticed,
replace the affected HO2S.

Open HO2S Signal Circuit of Faulty HO2S± A poor
connection or open in the HO2S signal circuit cancause the DTC to set during deceleration fuel mode.
An HO2S which is faulty and not allowing a full voltage
switch between the rich and lean thresholds can also
cause the condition. Operate the vehicle while
monitoring the HO2S voltage with a Tech 2. If the
HO2S is limited within a range between 300 mV to
600 mV, check the HO2S signal circuit wiring and
associated terminal connections.

If none of the above conditions are present, replace the
affected HO2S.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
3. DTC P0152 failing during deceleration fuel cutoff
mode operation may indicate a condition described
in the ªDiagnostic Aidsº above. If the DTC P0152
test passes while the Failure Records conditions are
being duplicated, an intermittent condition is
indicated.
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.
DTC P0152 ± HO2S Circuit High Voltage Bank 2 Sensor 1

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Install the Tech 2.
2. Engine is at operating temperature.
3. Operate the vehicle within the parameters specified
under ªConditions for Setting the DTCº criteria
included in Diagnostic Support.
4. Using a Tech 2, monitor Bank 2 HO2S 1 voltage.
Does the Bank 2 HO2S 1 voltage remain above the
specified value?
952 mV
(500 mV in
deceleration
fuel cut-off
mode)
Go to Step 4Go to Step 3
31. Ignition ªONº.
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor ªDTCº info for DTC P0152
until the DTC P0152 test runs.
5. Note the test result.
Does the Tech 2 indicate DTC P0152 failed this
ignition?
ÐGo to Step 4
Refer to
Diagnostic
Aids
41. Ignition ªOFFº.
2. Disconnect Bank 2 HO2S 1.
3. Ignition ªONº.
4. At HO2S Bank 2 Sensor 1 connector (PCM side)
use a DVM to measure voltages at the high and low
signal terminals.
Are the voltages in the specified range?
3-4 VGo to Step 5Go to Step 6

6E±199
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0152 ± HO2S Circuit High Voltage Bank 2 Sensor 1

 
StepNo Ye s Value(s) Action
5Repair short to voltage in signal circuit.
Is the action complete?
ÐVerify repairÐ
61. Ignition ªONº, engineªOFFº.
2. At Bank 2 HO2S 1 connector (PCM side) jumper
both the HO2S high and low signal circuits (PCM
side) to ground.
3. Using a Tech 2, monitor Bank 2 HO2S 1 voltage.
Is Bank 2 HO2S 1 voltage below the specified value?
10 mVGo to Step 7Go to Step 8
71. Disconnect the jumpers to ground from Bank 2
HO2S 1 PCM-side connector.
2. With the HO2S 1 connector disconnected, monitor
Bank 2 HO2S 1 voltage.
Is the Bank 2 HO2S 1 voltage between the specified
values?
425-475 mV
Refer to
Diagnostic
Aids
Go to Step 8
8Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
On-Vehicle Service in
Powertrain Control Module and Sensors for
procedures.
And also refer to latest Service Bulletin.
Check to see if the Latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.
Is the action complete?
ÐVerify repairÐ

6E±202
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0153 ± HO2S Slow Response Bank 2 Sensor 1

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2NOTE: If any DTCs are set, (except P0133, P1133,
P1134, P1153, and/or P1154), refer to those DTCs
before proceeding with this diagnostic chart.
1. Install the Tech 2.
2. Idle the engine at operating temperature.
3. Operate the vehicle within parameters specified
under ªConditions for Setting the DTCº criteria
included in Diagnostic Support.
4. Using a Tech 2, monitor ªDTCº info for DTC P0153
until the DTC P0153 test runs.
5. Note the test result.
Does the Tech 2 indicate DTC P0153 failed this
ignition?
ÐGo to Step 3
Refer to
Diagnostic
Aids
3Did the Tech 2 also indicate DTC P0153, P1133,
P1134, P1153, and/or P1154 test failed this ignition?
ÐGo to Step 17Go to Step 4
4Check for leaks at the pipe joints.
Are the joints leaking?
ÐGo to Step 5Go to Step 6
5Tighten the U-bolt nuts at the leaking joint.
Is your action complete?
ÐGo to Step 2Ð
6Check for gaskets that are damage or improperly
installed.
Are there damaged or misaligned gaskets?
ÐGo to Step 7Go to Step 8
71. Replace the damaged gaskets.
2. Align the connections.
3. Tighten the connections.
Is your action complete?
ÐGo to Step 2Ð
8Check for loose exhaust flange connections.
Are the flange connections loose?
ÐGo to Step 9Go to Step 10
9Tighten the stud nuts or bolts to specifications.
Is your action complete?
ÐGo to Step 2Ð
10Check for burned or corroded exhaust pipes.
Are the exhaust pipes burned or corroded?
ÐGo to Step 11Go to Step 12
11Replace the exhaust pipes, as required.
Is your action complete?
ÐGo to Step 2Ð
12Check for leaks at the exhaust manifold.
Are there leaks at the exhaust manifold?
ÐGo to Step 13Go to Step 14
13Tighten the bolts to specifications or replace the
manifold if necessary.
Is your action complete?
ÐGo to Step 2Ð

6E±203
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0153 ± HO2S Slow Response Bank 2 Sensor 1

 
StepNo Ye s Value(s) Action
141. Visually/physically inspect the following items:

Ensure that the Bank 2 HO2S 1 is securely
installed.

Check for corrosion on terminals.

Check terminal tension (at Bank 2 HO2S 1 and
at the PCM).

Check for damaged wiring.
Was a problem found in any of the above areas?
ÐGo to Step 18Go to Step 15
151. Disconnect Bank 2 HO2S 1.
2. Ignition ªONº.
3. Using a DVM at the PCM side of the HO2S 1
connector, measure the voltage between the high
signal circuit and ground.
Are both voltages in the specified range?
3-4 VGo to Step 16Go to Step 19
161. With Bank 2 HO2S 1 disconnected, jumper the high
and low (PCM side) signal circuits to ground.
2. Ignition ªONº.
3. Using a Tech 2, monitor the Bank 2 HO2S 1 voltage.
Does the Tech 2 indicate less than 10 mV and
immediately return to about 450 mV when the jumper is
removed?
ÐGo to Step 21Go to Step 22
17Replace the affected heated oxygen sensors.
NOTE: Before replacing the sensors, the cause of the
contamination must be determined and corrected.

Fuel contamination.

Use of improper RV sealant.

Engine oil/coolant consumption.
Is the action complete?
ÐVerify repairÐ
18Repair condition as necessary.
Is the action complete?
ÐVerify repairÐ
19Check for faulty PCM connections or terminal damage.
Is the action complete?
ÐVerify repairGo to Step 20
20Repair open, short or grounded signal circuit.
Is the action complete?
ÐVerify repairÐ
21Replace Bank 2 HO2S 1.
Is the action complete?
ÐVerify repairÐ
22Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
On-Vehicle Service in
Powertrain Control Module and Sensors for
procedures.
And also refer to latest Service Bulletin.
Check to see if the Latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.
Is the action complete?
ÐVerify repairÐ

6E±205
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
improper mating, broken locks, improperly formed or
damaged terminals, poor terminal-to-wire-connection,
and damaged harness.

Faulty HO2S heater or heater circuit ± With the ignition
ªONº, engine ªOFFº, the HO2S 1 voltage displayed on
the Tech 2 is normally 455-460 mV. A reading over
1000 mV indicates a signal line shorted to voltage. A
reading under 5 mV indicates a signal line shorted to
ground or signal lines shorted together. If not,
disconnect the HO2S and connect a test light between
the HO2S ignition feed and heater ground circuits. If
the test light does not light for 2 seconds when the
ignition is turned on, repair the open ignition feed or
sensor ground circuit as necessary. If the test light
lights and the HO2S signal and low circuits are OK,
replace the HO2S.

Intermittent test ± With the ignition ªONº, monitor the
HO2S signal voltage while moving the wiring harnessand related connectors. If the fault is induced, the
HO2S signal voltage will change. This may help isolate
the location of the malfunction.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
3. If the DTC P0154 test passes while the Failure
Records conditions are being duplicated, an
intermittent condition is indicated.
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.
DTC P0154 ±HO2S Circuit Insufficient Activity Bank 2 Sensor 1

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Install the Tech 2.
2. Run the engine at operating temperature.
3. Operate the engine above 1200 RPM for two
minutes.
Does the Tech 2 indicate Bank 2 HO2S 1 voltage
varying outside the specified values?
400-500 mVGo to Step 3Go to Step 4
31. Ignition ªONº, engine ªOFFº.
2. Review and record Tech 2 Failure Records data and
note parameters.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor ªDTCº info for DTC P0154
until the DTC P0154 test runs.
5. Note the test result.
Does the Tech 2 indicate DTC P0154 failed this
ignition?
ÐGo to Step 4
Refer to
Diagnostic
Aids
4Check for a damaged harness.
Was a problem found?
ÐVerify repairGo to Step 5
5Check for a poor Bank 2 HO2S 1 high and low circuit
terminal connections at the Bank 2 HO2S 1 harness
connector and replace terminal(s) if necessary.
Did any terminals require replacement?
ÐVerify repairGo to Step 6
6Check for a poor Bank 2 HO2S 1 high and low circuit
terminal connections at the PCM and replace
terminal(s) if necessary.
Did the terminal require replacement?
ÐVerify repairGo to Step 7

6E±206
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0154 ±HO2S Circuit Insufficient Activity Bank 2 Sensor 1

 
StepNo Ye s Value(s) Action
71. Ignition ªOFFº.
2. With the PCM disconnected, check continuity of the
Bank 2 HO2S 1 high circuit.
3. If the Bank 2 HO2S 1 high circuit measures over 5.0
ohms, repair open or poor connection as necessary.
Was a Bank 2 HO2S 1 high circuit problem found and
corrected?
ÐVerify repairGo to Step 8
81. Ignition ªOFFº.
2. With the PCM disconnected, check continuity of the
Bank 2 HO2S 1 low circuit.
3. If the Bank 2 HO2S 1 low circuit measures over 5.0
ohms, repair open or poor connection as necessary.
Was a Bank 2 HO2S 1 low circuit problem found and
corrected?
ÐVerify repairGo to Step 9
91. Ignition ªONº, engine ªOFFº.
2. Disconnect Bank 2 HO2S 1 and jumper the HO2S
high and low circuits (PCM side) to ground.
3. Using a Tech 2, monitor Bank 2 HO2S 1 voltage.
Is the Bank 2 HO2S 1 voltage in the specified range?
0-10 mVGo to Step 10Go to Step 11
10Replace Bank 2 HO2S 1.
Is the action complete?
ÐVerify repairÐ
11Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
On-Vehicle Service in
Powertrain Control Module and Sensors for
procedures.
And also refer to latest Service Bulletin.
Check to see if the Latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.
Is the action complete?
ÐVerify repairÐ

6E±207
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0155
HO2S Heater Circuit Open Bank 2 Sensor 1
060R200054
Circuit Description
Heated oxygen sensors are used to minimize the amount
of time required for closed loop fuel control operation and
to allow accurate catalyst monitoring. The oxygen sensor
heater greatly decreases the amount of time required for
fuel control sensors Bank 1 HO2S 1 and Bank 2 HO2S 1
to become active. Oxygen sensor heaters are required
by post-catalyst monitor sensors to maintain a sufficiently
high temperature which allows accurate exhaust oxygen
content readings further from the engine.
The powertrain control module (PCM) will run the heater
test only after a cold start (determined by engine coolant
and intake air temperature at the time of start-up) and only
once during an ignition cycle. When the engine is started
the PCM will monitor the HO2S voltage. When the Bank
HO2S voltage indicates a sufficiently active sensor, the
PCM looks at how much time has elapsed since start-up.
If the PCM determines that too much time was required
for the Bank 2 HO2S 1 to become active, a DTC P0155
will set. The time it should take the HO2S to reach
operating temperature is based on the total amount of air
that has passed through the mass air flow (MAF) sensor
and into the engine (more total air flow = shorter time to
HO2S activity).
Conditions for Setting the DTC

No related DTCs.

The engine has been running for over 120 seconds.
Ignition voltage is between 11 volts and 18 volts.

Heater signal is below 0.1A.

Bank 1 HO2S 2 voltage does not change more than
150 mV from the bias voltage (between
400 mV-500 mV) for a longer amount of time than it
should. The maximum amount of time to come up to
operating range is 120 seconds. This warm-up time
depends on the engine coolant temperature at start-up
and accumulated air flow since start-up.
Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp
(MIL) after the second consecutive trip in which the
fault is detected.

The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC

The PCM will turn the MIL ªOFFº on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condition is no longer present.

A history DTC P0155 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0155 can be cleared by using the Tech 2 ªClear
infoº function or by disconnecting the PCM battery
feed.