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Symptom List:
P0134-1/1 O2 SENSOR STAYS AT CENTER
P0140-1/2 O2 SENSOR STAYS AT CENTER
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P0134-1/1 O2 SENSOR STAYS AT
CENTER.
When Monitored and Set Condition:
P0134-1/1 O2 SENSOR STAYS AT CENTER
When Monitored: Engine running for greater than 121 second. Coolant Temperature
greater than 66ÉC (150.8ÉF). Engine in closed loop fuel control mode.
Set Condition: O2 signal voltage is between .35 volt and .58 volt for a total of 30 seconds
and than O2 signal volt is 1.5 volts for 60 seconds. One trip fault.
P0140-1/2 O2 SENSOR STAYS AT CENTER
When Monitored: Engine running for greater than 121 second. Coolant Temperature
greater than 66ÉC (150.8ÉF). Engine in closed loop fuel control mode. Vehicle Speed greater
than 40 MPH.
Set Condition: O2 signal voltage is between .35 volt and .58 volt for a total of 30 seconds
and than O2 signal volt is 1.5 volts for 60 seconds. Two trip fault.
POSSIBLE CAUSES
INTERMITTENT CONDITION
O2 SENSOR OPERATION
O2 SENSOR GROUND CIRCUIT OPEN
O2 SENSOR SIGNAL OPEN
O2 SENSOR GROUND CIRCUIT VOLTAGE DROP
O2 SENSOR SIGNAL CIRCUIT VOLTAGE DROP
PCM
TEST ACTION APPLICABILITY
1NOTE: Check for contaminates that may have damaged the O2 Sensor:
contaminated fuel, unapproved silicone, oil and coolant.
Turn the ignition on.
With the DRBIIIt, read DTC's.
Is the Good Trip displayed and equal to zero?All
Ye s®Go To 2
No®Go To 8
82
DRIVEABILITY - GAS
Page 3879 of 4284

Symptom:
P0135-1/1 O2 SENSOR HEATER FAILURE
When Monitored and Set Condition:
P0135-1/1 O2 SENSOR HEATER FAILURE
When Monitored: During vehicle shutdown after vehicle had been driven greater than 10
miles with throttle open for a minimum of 3 minutes. Battery voltage greater than 11.0
volts.
Set Condition: O2 sensor voltage continues to rise (instead of fall) after the diagnostics
has turned the ASD relay back on. Two trip fault.
POSSIBLE CAUSES
O2 HEATER ELEMENT
O2 SENSOR HEATER CONTROL CIRCUIT OPEN
O2 SENSOR HEATER CONTROL CIRCUIT SHORTED TO GROUND
ASD RELAY OUTPUT CIRCUIT OPEN
INTERMITTENT CONDITION
PCM
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, read DTC's.
Is the Good Trip display and equal to zero?All
Ye s®Go To 3
No®Go To 2
2 Turn the ignition off.
NOTE: Wait a minimum of 8 minutes to allow the O2 Sensor to cool down
before continuing the test. Allow the O2 Sensor voltage to stabilize between
0.4 to 0.6 volts.
Turn the ignition on.
With the DRBIIIt, actuate the O2 Heater Test.
With the DRBIIIt, monitor O2 Sensor voltage for at least 2 minutes.
Does the voltage stay between 0.4 and 0.6All
Ye s®Go To 3
No®Go To 8
85
DRIVEABILITY - GAS
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Symptom:
P0141-1/2 O2 SENSOR HEATER FAILURE
When Monitored and Set Condition:
P0141-1/2 O2 SENSOR HEATER FAILURE
When Monitored: During vehicle shutdown after the vehicle has been driven for greater
than 10 miles with the throttle open for a minimum of 3 minutes. Battery voltage greater
than 11.0 volts.
Set Condition: O2 sensor continues to rise, (instead of fall) after the diagnostics has
turned the ASD relay back on. Two trip fault.
POSSIBLE CAUSES
O2 HEATER ELEMENT
O2 SENSOR HEATER GROUND CIRCUIT OPEN
ASD RELAY OUTPUT CIRCUIT OPEN
INTERMITTENT CONDITION
PCM
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, read DTC's.
Is the Good Trip display and equal to zero?All
Ye s®Go To 3
No®Go To 2
2 Turn the ignition off.
NOTE: Wait a minimum of 8 minutes to allow the O2 Sensor to cool down
before continuing the test. Allow the O2 Sensor voltage to stabilize between
0.4 to 0.6 volts.
Turn the ignition on.
With the DRBIIIt, actuate the O2 Heater Test.
With the DRBIIIt, monitor O2 Sensor voltage for at least 2 minutes.
Does the voltage stay between 0.4 and 0.6 volts?All
Ye s®Go To 3
No®Go To 7
3NOTE: Allow the O2 sensor to cool down to room temperature.
Turn the ignition off.
Disconnect the O2 Sensor harness connector.
Measure the resistance across the O2 Sensor Heater element component side.
Is the resistance between 4.0 and 7.0 ohms?All
Ye s®Go To 4
No®Replace the O2 Sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
88
DRIVEABILITY - GAS
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Symptom:
P0171-1/1 FUEL SYSTEM LEAN
When Monitored and Set Condition:
P0171-1/1 FUEL SYSTEM LEAN
When Monitored: With the engine running in closed loop mode, the ambient/battery
temperature above 20 deg. F and altitude below 8000 ft.
Set Condition: If the PCM multiplies short term compensation by long term adaptive and
a certain percentage is exceeded for two trips, a freeze frame is stored, the MIL illuminates
and a trouble code is stored.
POSSIBLE CAUSES
INTERMITTENT CONDITION
RESTRICTED FUEL SUPPLY LINE
FUEL PUMP INLET STRAINER PLUGGED
FUEL PUMP MODULE
O2 SENSOR
O2 SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
O2 SENSOR HEATER OPERATION
TPS VOLTAGE GREATER THAN 0.92 VOLTS WITH THROTTLE CLOSED
TP SENSOR SWEEP
MAP SENSOR OPERATION
ECT SENSOR OPERATION
ENGINE MECHANICAL PROBLEM
FUEL FILTER/PRESSURE REGULATOR (HIGH)
PCM
TEST ACTION APPLICABILITY
1NOTE: Check for contaminates that may have damaged the O2 Sensor:
contaminated fuel, unapproved silicone, oil and coolant.
Turn the ignition on.
With the DRBIIIt, read DTC's.
Is the Good Trip displayed and equal to zero?All
Ye s®Go To 2
No®Go To 16
90
DRIVEABILITY - GAS
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Symptom:
P0172-1/1 FUEL SYSTEM RICH
When Monitored and Set Condition:
P0172-1/1 FUEL SYSTEM RICH
When Monitored: With the engine running in closed loop mode, the ambient/battery
temperature above 20 deg. F and altitude below 8000 ft.
Set Condition: If the PCM multiplies short term compensation by long term adaptive and
the result is below a certain value for two trips, a freeze frame is stored, the MIL
illuminates and a trouble code is stored.
POSSIBLE CAUSES
INTERMITTENT CONDITION
O2 SENSOR HEATER OPERATION
O2 SENSOR
EVAP PURGE SOLENOID OPERATION
O2 SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE
O2 SENSOR SIGNAL CIRCUIT OPEN
TPS VOLTAGE GREATER THAN 0.92 VOLTS WITH THROTTLE CLOSED
TP SENSOR SWEEP
MAP SENSOR OPERATION
ECT SENSOR OPERATION
ENGINE MECHANICAL PROBLEM
FUEL FILTER/PRESSURE REGULATOR (HIGH)
PCM
TEST ACTION APPLICABILITY
1NOTE: Check for contaminates that may have damaged the O2 Sensor:
contaminated fuel, unapproved silicone, oil and coolant.
Turn the ignition on.
With the DRBIIIt, read DTC's.
Is the Good Trip displayed and equal to zero?All
Ye s®Go To 2
No®Go To 15
95
DRIVEABILITY - GAS
Page 3895 of 4284

P0206-INJECTOR #6 CONTROL CIRCUIT
When Monitored: With battery voltage greater than 10 volts. Auto Shutdown Relay
energized. Engine speed less than 3000 rpm.
Set Condition: No inductive spike is detected after injector turn off.
POSSIBLE CAUSES
ASD RELAY OUTPUT CIRCUIT OPEN
INTERMITTENT CONDITION
FUEL INJECTOR
FUEL INJECTOR DRIVER CIRCUIT OPEN
FUEL INJECTOR DRIVER CIRCUIT SHORTED TO GROUND
PCM
TEST ACTION APPLICABILITY
1NOTE: Record the Freeze Frame Information that set along with the DTC.
Turn the ignition on.
With the DRBIIIt, read DTC's.
Is the Good Trip displayed and equal to zero?All
Ye s®Go To 2
No®Go To 7
2 Turn the ignition off.
Disconnect the Fuel Injector harness connector.
Measure the resistance of the Fuel Injector component side.
Is the resistance between 10 and 16 ohms?All
Ye s®Go To 3
No®Replace the Fuel Injector.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
3 Turn the ignition off.
Disconnect the Fuel Injector harness connector.
Remove the ASD Relay from the PDC.
Using a 12-volt test light connected to 12-volts, probe the ASD Relay Output circuit.
Does the test light illuminate brightly?All
Ye s®Go To 4
No®Repair the ASD Relay Output circuit for an open.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
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P0201-INJECTOR #1 CONTROL CIRCUIT ÐContinued
Page 3898 of 4284

P0305-CYLINDER #5 MISFIRE
When Monitored: Any time the engine is running, and the adaptive numerator has been
successfully updated.
Set Condition: When more than a 2% (1.5% LEV) misfire rate is measured during two
trips, or with a 10% to 30% misfire rate during one trip.
P0306-CYLINDER #6 MISFIRE
When Monitored: Any time the engine is running, and the adaptive numerator has been
successfully updated.
Set Condition: When more than a 2% misfire rate is measured during two trips, or with
a 10% to 30% misfire rate during one trip.
POSSIBLE CAUSES
MIS-FIRE CONDITIONS NO LONGER EXIST
FUEL SYSTEM PROBLEM
SECONDARY IGNITION OR MECHANICAL PROBLEM
ERRATIC CAM/CRANK SENSOR SIGNALS
ENGINE MECHANICAL PROBLEM
OTHER POSSIBLE CAUSES FOR MIS-FIRE
TEST ACTION APPLICABILITY
1Note: Repair all other PCM DTC's before continuing with this test.
With the DRBIIIt, read DTC's.
Is the MIS-FIRE GOOD TRIP counter displayed and equal to zero?All
Ye s®Go To 2
No®Go To 8
2 At this time the conditions that set the Misfire DTC are present.
With the DRBIIIt, select DTC's and RELATED FUNCTIONS. Read and record the
FREEZE FRAME DATA. Select OBD II MONITORS. Read and record the MIS-FIRE
SIMILAR CONDITIONS WINDOW DATA.
With these screens, attempt to duplicate the condition(s) that has set this DTC.
When the vehicle is operating in the SIMILAR CONDITIONS WINDOW, refer to the
WHICH CYLINDER IS MISFIRING screen.
Observe the WHICH CYLINDER IS MISFIRING screen for at least one minute.
Is the DRBIIItcounting mis-fires at this time?All
Ye s®Go To 3
No®Go To 8
104
DRIVEABILITY - GAS
P0300-MULTIPLE CYLINDER MIS-FIRE ÐContinued
Page 3902 of 4284

Symptom:
P0320-NO CRANK REFERENCE SIGNAL AT PCM
When Monitored and Set Condition:
P0320-NO CRANK REFERENCE SIGNAL AT PCM
When Monitored: Engine cranking.
Set Condition: No CKP signal is present during engine cranking, and at least 8 camshaft
position sensor signals have occurred.
POSSIBLE CAUSES
CHECKING INTERMITTENT CKP SIGNAL WITH LAB
CHECKING INTERMITTENT CMP SIGNAL WITH LAB
CHECKING INTERMITTENT WIRING WITH LAB SCOPE
INTERMITTENT CONDITION
8 VOLT SUPPLY CIRCUIT SHORTED TO GROUND
8 VOLT SUPPLY CIRCUIT OPEN
8 VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
CKP SENSOR SIGNAL CIRCUIT SHORTED GROUND
CKP SENSOR SIGNAL CIRCUIT OPEN
CKP SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE
CKP SENSOR SIGNAL SHORTED TO 8 VOLT SUPPLY CIRCUIT
SENSOR GROUND CIRCUIT OPEN
PCM - 8 VOLT SUPPLY
PCM - CKP SENSOR SIGNAL
CRANKSHAFT POSITION SENSOR
TEST ACTION APPLICABILITY
1 With the DRBIIIt, read the Current CKP State while cranking the engine.
Does the DRBIIItdisplay Current CKP State Present while cranking the engine.All
Ye s®Go To 2
No®Go To 6
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DRIVEABILITY - GAS