2002 ISUZU AXIOM turn signal

6E±194
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P0151 HO2S Circuit Low Voltage Bank 2 Sensor 1
060R200054
Circuit Description
The powertrain control module (PCM) supplies a bias
voltage of about 450 mV between the heated oxygen
sensor (HO2S) signal high and signal low circuits. When
measured with a 10 megaohm digital voltmeter, this may
display as low as 320 mV. The oxygen sensor varies the
voltage within a range of about 1000 mV when the
exhaust is rich, down through about 10 mV when exhaust
is lean. The PCM constantly monitors the HO2S signal
during ªclosed loopº operation and compensates for a rich
or lean condition by decreasing or increasing injector
pulse width as necessary. If the Bank 2 HO2S 1 voltage
remains excessively low for an extended period of time,
DTC P0151 will be set.
Conditions for Setting the DTC

No related DTCs.

The engine is operating in ªclosed loopº.

Engine coolant temperature is above 60
C (140
F).

ªClosed loopº commanded air/fuel ratio is between
14.5 and 14.8.

Bank 2 HO2S 1 signal voltage remains below 22 mV
during normal ªclosed loopº operation for a total of 77
seconds over a 90-second period of time.
Action Taken When the DTC Sets

The PCM will ON the MIL after second trip with
detected fault.
The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.

ªOpen loopº fuel control will be in effect.
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 P0151 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0151 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.
Diagnostic Aids
Check for the following conditions:

Heated oxygen sensor wiring ± The sensor pigtail may
be mispositioned and contacting the exhaust system.

Poor PCM to engine block grounds.

Fuel pressure ± The system will go lean if pressure is
too low. The PCM can compensate for some
decrease. However, if fuel pressure is too low, a DTC
P0151 may be set. Refer to
Fuel System Diagnosis.

Lean injector(s) ± Perform ªInjector Balance Testº.

Vacuum leaks ± Check for disconnected or damaged
vacuum hoses and for vacuum leaks at the intake
manifold, throttle body, EGR system, and PCV system.

6E±195
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Exhaust leaks ± An exhaust leak may cause outside air
to be pulled into the exhaust gas stream past the
HO2S, causing the system to appear lean. Check for
exhaust leaks that may cause a false lean condition to
be indicated.

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

Fuel contamination ± Water, even in small amounts,
can be delivered to the fuel injectors. The water can
cause a lean exhaust to be indicated. Excessive
alcohol in the fuel can also cause this condition. Refer
to
Fuel System Diagnosis for the procedure to check
for fuel contamination.
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 P0151 failing during operation may indicate a
condition described in the ªDiagnostic Aidsº above.
If the DTC P0151 test passes while the Failure
Records conditions are being duplicated, an
intermittent condition is indicate.
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 P0151 ± HO2S Circuit Low 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. Run the engine 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 below the
specified value?
22 mVGo to Step 4Go to Step 3
31. Ignition ªONº, engine ªOFFº, review and record
Tech 2 Failure Records data and note parameters.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using a Tech 2, monitor ªDTCº info for DTC P0151
until the DTC P0151 test runs.
4. Note test result.
Does the Tech 2 indicate DTC P0151 failed this
ignition?
ÐGo to Step 4
Refer to
Diagnostic
Aids
41. Turn ignition ªOFFº.
2. Disconnect the PCM.
3. Check the Bank 2 HO2S 1 high and low signal
circuits for a short to ground or a short to the heater
ground circuit.
Were Bank 2 HO2S 1 signal circuits shorted?
ÐGo to Step 5Go to Step 6
5Repair the Bank 2 HO2S 1 signal circuit.
Is the action complete?
ÐVerify repairÐ
61. Ignition ªOFFº.
2. Leave the PCM and HO2S 1 disconnected.
3. Check for continuity between the high and low
signal circuits.
Was there continuity between the high and low circuits?
ÐGo to Step 7Go to Step 8
7Repair the short between the high and low circuits.
Is the action complete?
ÐVerify repairÐ

6E±197
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P0152 HO2S Circuit High Voltage Bank 2 Sensor 1
060R200054
Circuit Description
The powertrain control module (PCM) supplies a bias
voltage of about 450 mV between the heated oxygen
sensor (HO2S) signal high and signal low circuits. When
measured with a 10 megaohm digital voltmeter, this may
display as low as 320 mV. The oxygen sensor varies the
voltage within a range of about 1000 mV when the
exhaust is rich, down through about 10 mV when exhaust
is lean. The PCM constantly monitors the HO2S signal
during ªclosed loopº operation and compensates for a rich
or lean condition by decreasing or increasing the injector
pulse width as necessary. If the Bank 2 HO2S 1 voltage
remains excessively high for an extended period of time,
DTC P0152 will be set.
Conditions for Setting the DTC

No related DTCs.

The engine is operating in ªclosed loopº.

The engine coolant temperature is above 60
C
(140
F).

Bank 2 HO2S 1 signal voltage remains above 952 mV
during normal ªclosed loopº operation for a total of 77
seconds over a 90-second period.
OR

Bank 2 HO2S 1 signal voltage remains above 500 mV
during deceleration fuel cutoff mode operation for up to
3 seconds.
Action Taken When the DTC Sets

The PCM will ªONº the MIL after second trip with
detected fault

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

ªOpen loopº fuel control will be in effect.
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 P0152 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0152 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.
Diagnostic Aids
Check for the following conditions:

Fuel pressure ± The system will go rich if pressure is
too high. The PCM can compensate for some
increase. However, if fuel pressure is too high, a DTC
P0152 may be set. Refer to
Fuel System Diagnosis.

Rich injector(s) ± Perform ªInjector Balance Testº.

Leaking injector ± Refer to
Fuel System Diagnosis.

Evaporative emissions (EVAP) system ± Check the
canister for fuel saturation. If the canister is full of fuel,

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±204
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P0154 HO2S Circuit Insufficient Activity Bank 2 Sensor 1
060R200054
Circuit Description
The powertrain control module (PCM) supplies a bias
voltage of about 450 mV between the heated oxygen
sensor (HO2S) high and low circuits. When measured
with a 10 megaohm digital voltmeter, this may display as
low as 320 mV. The oxygen sensor varies the voltage
within a range of about 1000 mV when the exhaust is rich,
down through about 10 mV when exhaust is lean. The
PCM constantly monitors the HO2S signal during ªclosed
loopº operation and compensates for a rich or lean
condition by decreasing or increasing injector pulse width
as necessary. If the Bank 2 HO2S 1 voltage remains at or
near the 450 mV bias for an extended period of time, DTC
P0154 will be set, indicating an open sensor signal or
sensor low circuit.
Heated oxygen sensors are used to minimize the amount
of time required for ªclosed loopº 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 for accurate exhaust oxygen
content readings further from the engine.
Conditions for Setting the DTC

No related DTCs.

Engine coolant temperature is above 60
C (140
F).
The engine has been running for over 5 seconds.

Oxygen sensor heater is functioning properly.

Bank 2 HO2S 1 signal voltage remains between
400 mV and 500 mV for a total of 77 seconds over a
90-second period of time.
Action Taken When the DTC Sets

The PCM will ON the MIL after second trip with
detected fault.

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

ªOpen loopº fuel control will be in effect.
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 P0154 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0154 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.
Diagnostic Aids
Check for the following conditions:

Poor connection or damaged harness ± Inspect the
harness connectors for backed-out terminals,

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±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.

6E±210
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P0157 HO2S Circuit Low Voltage Bank 2 Sensor 2
060R200054
Circuit Description
To control emissions of hydrocarbons (HC), carbon
monoxide (CO), and oxides of nitrogen (NOx), a
three-way catalytic converter is used. The catalyst within
the converter promotes a chemical reaction which
oxidizes the HC and CO present in the exhaust gas,
converting them into harmless water vapor and carbon
dioxide. The catalyst also reduces NOx, converting it to
nitrogen. The powertrain control module (PCM) has the
ability to monitor this process using the Bank 2 HO2S 1
and the Bank 2 HO2S 2 heated oxygen sensors. The
Bank 2 HO2S 1 sensor produces an output signal which
indicates the amount of oxygen present in the exhaust
gas entering the three-way catalytic converter. The Bank
2 HO2S 2 sensor produces an output signal which
indicates the oxygen storage capacity of the catalyst; this
in turn indicates the catalyst's ability to convert exhaust
gases efficiently. If the catalyst is operating efficiently, the
Bank 2 HO2S 1 signal will be far more active than that
produced by the Bank 2 HO2S 2 sensor. If the Bank 2
HO2S 2 signal voltage remains excessively low for an
extended period of time, DTC P0157 will be set.
Conditions for Setting the DTC

No related DTCs.

The engine is operating in ªclosed loopº.

Engine coolant temperature is above 60
C (140
F).
ªClosed loopº commanded air/fuel ratio is between
14.5 and 14.8

Bank 2 HO2S 2 signal voltage remains below 22 mV
during normal ªclosed loopº operation for a total of 106
seconds over a 125-second period of time.
OR

Bank 2 HO2S 2 signal voltage remains below 400 mV
during ªpower enrichmentº mode fuel control operation
for up to 5 seconds.
Action Taken When the DTC Sets

The PCM will ON the MIL after second trip with
detected fault.

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 P0157 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0157 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.