2002 ISUZU AXIOM heater

6E±220
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Aids
Check for the following conditions:

Poor connection at PCM ± Inspect harness connectors
for backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.

Damaged harness ± Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
display on the Tech 2 while moving connectors and
wiring harnesses related to the sensor. A change in the
display will indicate the location of the fault.
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.2. The HO2S should be allowed to cool before
performing this test. If the HO2S heater is
functioning, the signal voltage will gradually increase
or decrease as the sensor element warms. If the
heater is not functioning, the HO2S signal will
remain near the 450 mV bias voltage.
4. This ensures that the ignition feed circuit to the
HO2S is not open or shorted. The test light should
be connected to a good chassis ground, in case the
HO2S low or HO2S heater ground circuit is faulty.
5. This checks the HO2S heater ground circuit.
6. This checks for an open or shorted HO2S heater
element.
11.An open HO2S signal or low circuit can cause the
HO2S heater to appear faulty. Check these circuits
before replacing the sensor.
DTC P0161 ± HO2S Heater Circuit Bank 2 Sensor 2

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2NOTE: If the engine has just been operating, allow the
engine to cool for at least 15 minutes before
proceeding.
1. Remove the fuel pump relay.
2. Connect a fused jumper at the fuel pump relay
socket, between the battery positive at the relay and
the relay wire that leads to the fuel pump and HO2S
fuses.
3. Ignition ªOFFº.
4. Install a Tech 2.
5. Ignition ªONº, engine ªOFFº.
6. Monitor the Bank 2 HO2S 2 voltage for several
minutes.
Did the HO2S voltage go from bias voltage to above or
below the specified values?
Above
650 mV or
Below
250 mV
Refer to
Diagnostic
Aids
Go to Step 3
3Inspect the fuse for the Bank 2 HO2S 2 ignition feed.
Is the fuse open?
ÐGo to Step 15Go to Step 4
41. Ignition ªOFFº.
2. Raise the vehicle.
3. Disconnect the Bank 2 HO2S 2 electrical connector.
4. Using a test light connected to a known good ground
(do not use Bank 2 HO2S 2 heater ground or Bank 2
HO2S 2 low), probe the ignition feed circuit at the
Bank 2 HO2S 2 electrical connector (PCM harness
side).
Does the test light illuminate?
ÐGo to Step 5Go to Step 7
5Connect the test light between the Bank 2 HO2S 2
ignition feed and the Bank 2 HO2S 2 heater ground.
Does the test light illuminate?
ÐGo to Step 6Go to Step 8

6E±221
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0161 ± HO2S Heater Circuit Bank 2 Sensor 2

 
StepNo Ye s Value(s) Action
61. Allow the HO2S to cool for at least 15 minutes.
2. Using a DVM, measure resistance between the
Bank 2 HO2S 2 ignition feed and the Bank 2 HO2S 2
heater ground at the Bank 2 HO2S 2 pigtail.
Is the HO2S resistance within the specified values?
3-6 ohmsGo to Step 9Go to Step 10
7Repair the open Bank 2 HO2S 2 ignition feed circuit to
Bank 2 HO2S 2.
Is the action complete?
ÐVerify repairÐ
8Repair the open Bank 2 HO2S 2 heater ground circuit.
Is the action complete?
ÐVerify repairÐ
91. Check for a poor connection at the Bank 2 HO2S 2
harness terminals.
2. If a poor connection is found, replace the terminals.
Was a poor connection found?
ÐVerify repairGo to Step 10
101. Ignition ªOFFº.
2. Disconnect the PCM and check the continuity of the
Bank 2 HO2S 2 signal circuit and the Bank 2 HO2S
2 low circuit.
3. If the Bank 2 HO2S 2 signal circuit or HO2S low
circuit measures over 5 ohms, repair the open or
poor connection as necessary.
Was a problem found?
ÐVerify repairGo to Step 11
111. Ignition ªOFFº.
2. Disconnect the PCM and check the continuity of the
Bank 2 HO2S 2 signal circuit and the Bank 2 HO2S
2 low circuit.
3. If the Bank 2 HO2S 2 signal circuit or HO2S low
circuit measures over 5 ohms, repair the open or
poor connection as necessary.
Was a problem found?
ÐVerify repairGo to Step 12
12Check for a poor Bank 2 HO2S 2 low circuit terminal
connection at the PCM and replace the terminal if
necessary.
Did the terminal require replacement?
ÐVerify repairGo to Step 13
13Check for a poor Bank 2 HO2S 2 high circuit terminal
connection at the PCM and replace the terminal if
necessary.
Did the terminal require replacement?
ÐVerify repairGo to Step 14
14Replace Bank 2 HO2S 2.
Is the action complete?
ÐVerify repairÐ
15Locate and repair the short to ground in the Bank 2
HO2S 2 ignition feed circuit and replace the faulty fuse.
Is the action complete?
ÐVerify repairÐ

6E±404
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P1133 HO2S Insufficient Switching Bank 1 Sensor 1
060R200054
Circuit Description
The powertrain control module (PCM) monitors the
heated oxygen sensor (HO2S) activity for 90 seconds
after ªclosed loopº and stoichiometric operation have
been enabled. During this test period the PCM counts the
number of times that the HO2S signal voltage crosses the
rich-to-lean and lean-to-rich threshold. If the PCM
determines that the HO2S did not switch enough times,
DTC P1133 will be set.
A lean-to-rich switch is determined when the HO2S
voltage changes above and below 450 mV.
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

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

Engine is operating in ªclosed loopº.

The engine has been running at least one minute.

Canister purge duty cycle is greater than 2%.

Engine speed is between 1500 RPM and 3000 RPM.
Mass air flow (MAF) is between 9 g/second and 42
g/second.

Above conditions are present for 3 seconds.

90 seconds after ªclosed loopº and stoichiometric
operation have been achieved, the PCM monitors the
oxygen sensor as it switches above and below 450 mV.
If fewer than 23 rich-to-lean and lean-to-rich switches
are detected, DTC P1133 will be set.
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.

ºOpen loopº fuel control will be in effect.

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 P1133 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P1133 can be cleared by using Tech 2 ªClear Infoº
function or by disconnecting the PCM battery feed.

6E±405
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Aids
A malfunction in the HO2S heater ignition feed or ground
circuit may cause a DTC P1133 to set. Check HO2S
heater circuitry for intermittent faults or poor connections.
If connections and wiring are OK and DTC P1133
continues to set, replace the Bank 1 HO2S 1.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help to 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 condition that affects other heated oxygen sensors
indicates probable contamination. To avoid
damaging the replacement sensors, correct the
condition which caused the contamination before
replacing the affected sensors.
5. This step checks for conditions which may cause the
heated oxygen sensor to appear faulty. Correct any
of the described conditions if present.
11.To avoid damaging replacement sensors, correct the
condition which caused the contamination before
replacing the affected sensors.
DTC P1133 ± HO2S Insufficient Switching Bank 1 Sensor 1

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2IMPORTANT:If any DTCs are set (except P1153 or
P1154) refer to those DTCs before proceeding with this
diagnostic chart.
1. Engine idling at operating temperature.
2. Operating the vehicle within parameters specified
under ªConditions for Setting the DTCº criteria
included in Diagnostic Support.
3. Using a Tech 2, monitor ªDTCº info for DTC P1133
until the DTC P1133 test runs.
4. Note the test result.
Does the Tech 2 indicate DTC P1133 failed this
ignition?
ÐGo to Step 3
Refer to
Diagnostic
Aids
3Did the Tech 2 also indicate that the P1153 or P1154
tests failed?
ÐGo to Step 20Go to Step 4
4Check for leaks at the exhaust pipe joints.
Are the joints leaking?
ÐGo to Step 5Go to Step 6
5Tighten the bolt/nuts at the leaking joints.
Is your action complete?
ÐGo to Step 2Ð
6Check for gaskets that are damaged 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

6E±408
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P1134 HO2S Transition Time Ratio Bank 1 Sensor 1
060R200054
Circuit Description
The powertrain control module (PCM) monitors the
heated oxygen sensor (HO2S) activity for 90 seconds
after ªclosed loopº and stoichiometric operation have
been established. During the monitoring period the PCM
counts the number of times that the HO2S responds from
rich-to-lean and from lean-to-rich and adds the amount of
time it took to complete all transitions. With this
information, an average time for all transitions can be
determined. The PCM then divides the rich-to-lean
average by the lean-to-rich average to obtain a ratio. If
the HO2S transition time ratio is not within this range,
DTC P1134 will be set, indicating that the oxygen sensor
is not responding as expected to changes in exhaust
oxygen content.
Conditions for Setting the DTC

No related DTCs.

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

Engine is operating in ªclosed loopº,

The engine has been running at least one minute.

Canister purge duty cycle is greater than 2%.

Engine speed is between 1500 RPM and 3000 RPM.

Mass air flow (MAF) is between 18 g/second and 42
g/second.

Above conditions are present for a 3-second
monitoring period.
90 seconds after ªclosed loopº and stoichiometric
operation have been enabled, Bank 1 HO2S 1
transition ratio between lean-to-rich and rich-to-lean is
less than 0.44 or greater than 3.8.
Action Taken When the DTC Sets

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

ºOpen loopº fuel control will be in effect.

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 P1134 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P1134 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.
Diagnostic Aids
A malfunction in the HO2S heater ignition feed or ground
circuit may cause a DTC P1134 to set. Check HO2S
heater circuitry for intermittent faults or poor connections.
If connections and wiring are OK and DTC P1134
continues to set, replace the Bank 1 HO2S 1.

6E±412
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P1153 HO2S Insufficient Switching Bank 2 Sensor 1
060R200054
Circuit Description
The powertrain control module (PCM) monitors the
heated oxygen sensor (HO2S) activity for 90 seconds
after ªclosed loopº and stoichiometric operation have
been enabled. During this test period the PCM counts the
number of times that the HO2S signal voltage crosses the
rich-to-lean and lean-to-rich thresholds. If the PCM
determines that the HO2S did not switch enough times,
DTC P1153 will be set.
A lean-to-rich switch is determined when the HO2S
voltage changes above and below 450 mV.
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

The engine is operating in ªclosed loopº,

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

The engine has been running for over 60 seconds.

Canister purge duty cycle is greater than 2%.

Engine speed is between 1500 RPM and 3000 RPM.
Mass air flow is between 8 g/second and 42 g/second.

Above conditions are present for a 3 seconds.

90 seconds after ªclosed loopº and stoichiometric
operation have been enabled, the PCM monitors the
oxygen sensor switching above and below 450 mV. If
fewer than 27 rich-to-lean and lean-to-rich switches for
Bank 2 HO2S 1 are detected, DTC P1153 will set.
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.

ºOpen loopº fuel control will be in effect.

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 P1153 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P1153 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.

6E±413
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Aids
A malfunction in the HO2S heater ignition feed or ground
circuit may cause a DTC P1153 to set. Check HO2S
heater circuitry for intermittent faults or poor connections.
If connections and wiring are OK and DTC P1153
continues to set, replace the Bank 2 HO2S 1.
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 condition that affects other heated oxygen sensors
indicates probable contamination. To avoid
damaging replacement sensors, correct the
condition which caused the contamination before
replacing the affected sensors.
5. This step checks for conditions which may cause the
heated oxygen sensor to appear faulty. Correct any
of the described conditions if present.
8. To avoid damaging replacement sensors, correct the
condition which caused the contamination before
replacing the affected sensors.
DTC P1153 ± HO2S Insufficient Switching 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
2IMPORTANT:If any DTCs are set, (except P1133
and/or P1134), refer to those DTCs before proceeding
with this diagnostic chart.
1. Idle the engine at operating temperature.
2. Operate the vehicle within parameters specified
under ªConditions for Setting the DTCº criteria
included in Diagnostic Support.
3. Using a Tech 2, monitor ªDTCº info for DTC P1153
until the DTC P1153 test runs.
Note the test result.
Does Tech 2 indicate DTC failed this ignition?
ÐGo to Step 3
Refer to
Diagnostic
Aids
3Did the Tech 2 also indicate P1133 and/or P1134 test
failed?
ÐGo to Step 20Go to Step 4
4Check for leaks at the exhaust pipe joints.
Are the joints leaking?
ÐGo to Step 5Go to Step 6
5Tighten the U-bolt nuts at the leaking joints.
Is your action complete?
ÐGo to Step 2Ð
6Check for gaskets that are damaged 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

6E±416
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P1154 HO2S Circuit Transition Time Ratio Bank 2 Sensor 1
060R200054
Circuit Description
The powertrain control module (PCM) monitors the
heated oxygen sensor (HO2S) activity for 90 seconds
after ªclosed loopº and stoichiometric operation have
been enabled. During the monitor period the PCM counts
the number of times that the HO2S responds from
rich-to-lean and from lean-to-rich and adds the amount of
time it took to complete all transitions. With this
information, an average time for all transitions can be
determined. The PCM then divides the rich-to-lean
average by the lean-to-rich average to obtain a ratio. If
the HO2S transition time ratio is not within this range,
DTC P1154 will be set, indicating that the oxygen sensor
is not responding as expected to changes in exhaust
oxygen content.
Conditions for Setting the DTC

No related DTCs.

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

The engine is operating in ªclosed loopº,

The engine has been running at least one minute.

Canister purge duty cycle is greater than 2%.

Engine speed is between 1500 RPM and 3000 RPM.

Mass air flow is between 18 g/second and 42 g/second.

Above conditions are present for a 3-second
monitoring period.
90 seconds after ªclosed loopº and stoichiometric
operation have been enabled, Bank 2 HO2S 1
transition ratio between lean to rich and rich to lean is
less than 0.44 or greater than 3.8.
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.

ºOpen loopº fuel control will be in effect.

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 P1154 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P1154 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.
Diagnostic Aids
A multifunction in the HO2S heater ignition feed or ground
circuit may cause a DTC P1154 to set. Check HO2S
heater circuitry for intermittent faults or poor connections.