check engine light ISUZU AXIOM 2002 Service Service Manual

6E±141
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Damaged harness ± Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
MAP 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.
If DTC P0106 cannot be duplicated, the information
included in the Failure Records data can be useful indetermining vehicle mileage since the DTC was last set.
If it is determined that the DTC occurs intermittently,
performing the DTC P1107 Diagnostic Chart may isolate
the cause of the fault.
DTC P0106 ± MAP System Performance

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªONº, engine ªOFFº.
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 P0106.
Does the Tech 2 indicate DTC P0106 failed?
ÐGo to Step 4Go to Step 3
31. Check for the following conditions:

Vacuum hoses disconnected, damaged, or
incorrectly routed

Intake manifold vacuum leaks

Vacuum leaks at throttle body

Vacuum leaks at EGR valve flange and pipes

Crankcase ventilation valve faulty, missing or
incorrectly installed.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repair
Refer to
Diagnostic
Aids
41. Disconnect the MAP sensor electrical connector.
2. Observe the MAP value displayed on the Tech 2.
Is the MAP value near the specified value?
11 kPaGo to Step 5Go to Step 13
51. Connect a test light between B+ and the MAP
sensor signal circuit at the MAP sensor harness
connector.
2. Observe the MAP value displayed on the Tech 2.
Is the MAP value near the specified value?
105 kPaGo to Step 6Go to Step 9
61. Jumper the 5 volt reference circuit and the MAP
signal circuit together at the MAP sensor harness
connector.
2. Observe the MAP value displayed on the Tech 2.
Is the MAP value near the specified value?
104 kPaGo to Step 7Go to Step 8
71. Ignition ªOFFº.
2. Disconnect the PCM and check the sensor ground
circuit for high resistance, an open between the
PCM and the MAP sensor, or for a poor connection
at the PCM.
3. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 11

6E±144
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
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
MAP 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.If DTC P0107 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.
If it is determined that the DTC occurs intermittently,
performing the DTC P0107 Diagnostic Chart may isolate
the cause of the fault.
DTC P0107 ± MAP Sensor Circuit Low Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªONº, engine ªOFFº.
2. With the throttle closed, observe the MAP value
displayed on the Tech 2.
Is the MAP value near the specified value?
0 V 11 kPa
at sea level
Go to Step 4Go to Step 3
31. Ignition ªONº, engine ªOFFº.
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 P0107.
Does the Tech 2 indicate DTC P0107 failed?
ÐGo to Step 4
Refer to
Diagnostic
Aids
41. Ignition ªOFFº.
2. Disconnect the MAP sensor electrical connector.
3. Jumper the 5 volt reference circuit and the MAP
signal together at the MAP sensor harness
connector.
4. Ignition ªONº.
5. Observe the MAP value displayed on the Tech 2.
Is the MAP value near the specified value? (If no, start
with diagnosis chart for other sensors in the circuit and
see if 5V returns.)
5 V 104 kPaGo to Step 10Go to Step 5
51. Disconnect the jumper.
2. Connect a test light between B+ and the MAP
sensor signal circuit at the MAP sensor harness
connector.
3. Observe the MAP value displayed on the Tech 2.
Is the MAP value near the specified value.
5 V 104 kPaGo to Step 6Go to Step 8
61. Ignition ªOFFº.
2. Disconnect the PCM and check the 5 volt reference
circuit for an open or short to ground.
3. If the 5 volt reference circuit is open or shorted to
ground, repair it as necessary.
Was the 5 volt reference circuit open or shorted to
ground?
ÐVerify repairGo to Step 7
7Check the 5 volt reference circuit for a poor connection
at the PCM and replace the terminal if necessary.
Did the terminal require replacement?
ÐVerify repairGo to Step 11

6E±147
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
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
MAP 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.If DTC P0108 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set. If
it is determined that the DTC occurs intermittently,
performing the DTC P1108 Diagnostic Chart may isolate
the cause of the fault.
DTC P0108 ± MAP Sensor Circuit High Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. If the engine idle is rough, unstable or incorrect,
repair the idle problem before using this chart. Refer
to
Symptoms section.
2. With the engine idling, note the MAP value on the
Tech 2.
Is the MAP reading above the specified value?
90 kPaGo to Step 4Go to Step 3
31. Ignition ªONº, engine ªOFFº.
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 P0108.
Does the Tech 2 indicate DTC P0108 failed this
ignition?
ÐGo to Step 4
Refer to
Diagnostic
Aids
41. Ignition ªOFFº.
2. Disconnect the MAP sensor electrical connector.
3. Ignition ªONº.
4. Note the MAP sensor voltage displayed on the Tech
2. (If no, start with diagnostic chart for other sensors
in the circuit and see if 5V returns.)
Is the MAP sensor voltage at the specified value?
11 kPa 0.0
V
Go to Step 5Go to Step 6
5Probe the sensor ground circuit with a test light to B+.
Is the test light ªONº?
ÐGo to Step 7Go to Step 9
61. Check the MAP signal circuit for a short to voltage or
a short to the 5 volt reference circuit.
2. If the MAP sensor signal circuit is shorted, repair
circuit as necessary.
Was the MAP sensor signal circuit shorted?
ÐVerify repairGo to Step 11
71. Check for a poor sensor ground terminal connection
at the MAP sensor electrical connector.
2. If a problem is found, replace the faulty terminal.
Did the terminal require replacement?
ÐVerify repairGo to Step 8
8Check for a plugged or leaking vacuum supply to the
MAP sensor.
Is the vacuum supply plugged or leaking?
ÐVerify repairGo to Step 12
91. Check for a poor sensor ground terminal connection
at the PCM.
2. If a problem is found, replace the faulty terminal.
Did the terminal require replacement?
ÐVerify repairGo to Step 10

6E±177
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Aids
Check for the following conditions:

Poor connection or damaged harness ± Inspect the
harness connectors for backed-out terminals,
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, after a cool down period, 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. 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 harness
and 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 P0134 test passes while the Failure
Records conditions are being duplicated, an
intermittent conditions 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 P0134 ±HO2S Circuit Insufficient Activity 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
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 1 HO2S 1 voltage
varying outside the specified values?
400-500 mVGo to Step 3Go to Step 4
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 P0134
until the DTC P0134 test runs.
4. Note the test result.
Does the Tech 2 indicate DTC P0134 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 poor Bank 1 HO2S 1 high and low circuit
terminal connections at the Bank 1 HO2S 1 harness
connector and replace terminal(s) if necessary.
Did any terminals require replacement?
ÐVerify repairGo to Step 6
6Check for poor Bank 1 HO2S 1 high and low circuit
terminal connections at the PCM and replace terminals
if necessary.
Did any terminals require replacement?
ÐVerify repairGo to Step 7

6E±180
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
ECT 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. 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. Checks the HO2S heater ground circuit.
6. Checks or an open or shorted HO2S heater element.
10.An open HO2S signal or low circuit can cause the
HO2S heater to appear faulty. Check these circuits
before replacing the sensor.
DTC P0135 ± HO2S Heater Circuit 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
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 1 HO2S 1 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 1 HO2S 1 ignition feed.
Is the fuse open?
ÐGo to Step 15Go to Step 4
41. Ignition ªOFFº.
2. Raise the vehicle.
3. Disconnect the Bank 1 HO2S 1 electrical connector.
4. Using a test light connected to a good ground (do
not use Bank 1 HO2S 1 heater ground or Bank 1
HO2S 1 low), probe the ignition feed circuit at the
Bank 1 HO2S 1 electrical connector (PCM harness
side).
Does the test light illuminate?
ÐGo to Step 5Go to Step 7
5Connect the test light between the Bank 1 HO2S 1
ignition feed and the Bank 1 HO2S 1 heater ground.
Does the test light illuminate?
ÐGo to Step 6Go to Step 8

6E±189
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Aids
Check for the following conditions:

Poor connection or damaged harness± Inspect the
harness connectors for backed-out terminals,
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
ignitionªONº, engine ªOFFº, the HO2S voltage
displayed on a Tech 2 should gradually drop to below
250 mV. 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, 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 harness
and 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 P0140 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 P0140 ± HO2S Circuit Insufficient Activity BANK 1 SENSOR 2

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 1 HO2S 2 voltage
varying outside the specified values?
425-475 mVGo to Step 3Go to Step 4
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 P0140
until the DTC P0140 test runs.
4. Note the test result.
Does the Tech 2 indicate DTC P0140 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 poor Bank 1 HO2S 2 high and low circuit
terminal connections at the Bank 1 HO2S 2 harness
connector and replace terminal(s) if necessary.
Did any terminals require replacement?
ÐVerify repairGo to Step 6
6Check for poor Bank 1 HO2S 2 high and low circuit
terminal connections at the PCM and replace
terminal(s) if necessary.
Did any terminals require replacement?
ÐVerify repairGo to Step 7
71. Ignition ªOFFº.
2. With the PCM disconnected, check continuity of the
Bank 1 HO2S 2 high circuit.
3. If the Bank 1 HO2S 2 high circuit measures over 5.0
ohms, repair open or poor connection as necessary.
Was a Bank 1 HO2S 2 high circuit problem found and
corrected?
ÐVerify repairGo to Step 8

6E±192
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

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 P0141 ± HO2S Heater Circuit Bank 1 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 1 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 Bank 1 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 1 HO2S 2 electrical connector.
4. Using a test light connected to a good ground (do
not use Bank 1 HO2S 2 heater ground or Bank 1
HO2S 2 low), probe the ignition feed circuit at the
Bank 1 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 1 HO2S 2
ignition feed and the Bank 1 HO2S 2 heater ground.
Does the test light illuminate?
ÐGo to Step 6Go to Step 8

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±208
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. 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. Checks the HO2S heater ground circuit.
6. Checks for an open or shorted HO2S heater
element.
10.An open HO2S signal or low circuit can cause the
HO2S heater to appear faulty. Check these circuits
before replacing the sensor.
DTC P0155 ± HO2S Heater Circuit Open 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 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 1 HO2S 1 voltage for several
minutes.
Did the HO2S voltage go from bias voltage to above or
below the specified value?
Above
650 mV or
below
250 mV
Refer to
Diagnostic
Aids
Go to Step 3
3Inspect the fuse for the Bank 2 HO2S 1 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 1 electrical connector.
4. Using a test light connected to a known good ground
(do not use Bank 2 HO2S 1 heater ground or Bank 2
HO2S 1 low), probe the ignition feed circuit at the
Bank 2 HO2S 1 electrical connector (PCM harness
side).
Does the test light illuminate?
ÐGo to Step 5Go to Step 7
5Connect the test light between Bank 2 HO2S 1 ignition
feed and Bank 2 HO2S 1 heater ground.
Does the test light illuminate?
ÐGo to Step 6Go to Step 8

6E±217
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0160 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,
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 voltage displayed on a
Tech 2 should gradually drop to below 250 mV. 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, 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 harness
and 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 P0160 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 P0160 ± HO2S Circuit Insufficient Activity 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
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 2 voltage
varying outside the specified values?
425-475 mVGo to Step 3Go to Step 4
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 P0160
until the DTC P0160 test runs.
4. Note the test result.
Does the Tech 2 indicate DTC P0160 failed this
ignition?
ÐGo to Step 4
Refer to
Diagnostic
Aids
4Check for a damaged harness.
Was problem found?
ÐVerify repairGo to Step 5
5Check for poor Bank 2 HO2S 2 high and low circuit
terminal connections at the Bank 2 HO2S 2 harness
connector and replace terminal(s) if necessary.
Did either terminal require replacement?
ÐVerify repairGo to Step 6
6Check for poor Bank 2 HO2S 2 high and low circuit
terminal connections at the PCM and replace terminals
if necessary.
Did any terminals require replacement?
ÐVerify repairGo to Step 7