TEST ACTION APPLICABILITY
3 Ignition Off
Disconnect the ECT Sensor Electrical Connector.
Note: Check connectors - Clean/repair as necessary.
Connect a jumper wire between the ECT Sensor Signal Circuit and an engine ground.
Turn the ignition on, with the engine not running.
With the DRB, read the Engine Coolant Temperature Sensor voltage.
Is the voltage below 1.0 volt?All
Ye s®Repair the open ECT Sensor Ground Circuit.
Perform Powertrain Verification Test VER-5A.
No®Go To 4
4 Ignition Off
Disconnect the ECT Sensor Connector.
Note: Check connectors - Clean/repair as necessary.
Disconnect the PCM Connector.
Note: Check connectors - Clean/repair as necessary.
Using an Ohmmeter, measure the ECT Sensor Signal Circuit from the PCM to the
ECT.
Is the resistance below 5.0 ohms?All
Ye s®Go To 5
No®Repair the open ECT Sensor Signal Circuit.
Perform Powertrain Verification Test VER-5A.
5 Ignition Off
If there are no potential causes remaining, the PCM is assumed to be defective.
View repair options.All
Repair
Replace the PCM.
Perform Powertrain Verification Test VER-5A.
6 Ignition On, Engine Not Running
Use the schematic as a guide and wiggle the ECT Sensor Connector & Harness.
Monitor the DRB display.
Was there any ECT Sensor voltage change?All
Ye s®Repair the Harness or Connector that caused the voltage change.
Perform Powertrain Verification Test VER-5A.
No®Go To 7
7 Ignition Off
Using the schematic as a guide, inspect the Wiring and Connectors.
Were any problems found?All
Ye s®Repair as necessary.
Perform Powertrain Verification Test VER-5A.
No®Test Complete.
41
DRIVEABILITY
P-0118 ECT SENSOR VOLTAGE TOO HIGH ÐContinued
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Symptom:
P-0125 CLOSED LOOP TEMP NOT REACHED
When Monitored and Set Condition:
P-0125 CLOSED LOOP TEMP NOT REACHED
When Monitored: After engine is started, for ten minutes.
Set Condition: The engine temperature does not go above 10 degrees C (50 degrees F) by
13 minutes after the engine is started for 2 consecutive trips.
POSSIBLE CAUSES
PCM CONNECTOR AND TERM DAM, PSHD OUT, OR MISWIRED
ECT SENSOR CONN AND TERM DAM, PSHD OUT, MISWIRED
ECT SENSOR RESISTANCE >=11.00 K OHMS
PCM DEFECTIVE
THERMOSTAT DEFECTIVE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, read the FREEZE FRAME DATA.
Using the FREEZE FRAME DATA, attempt to duplicate the condition that has set
this fault.
Note that the DTC is a 2 trip failure.
Does P0121 reset?All
Ye s®Go To 3
No®Go To 2
2 The conditions required to set the DTC are no longer present.
Ensure the engine cooling system is operating properly, coolant level is at specifica-
tion, and no external or internal coolant leaks. Refer to the appropriate service
category for cooling system information.
Is the Cooling System operating correctly?All
Ye s®Test complete
No®Repair as necessary.
Perform Powertrain verification Test VER-5A
3 Ignition off.
Disconnect the ECT Sensor Connector.
Note: Check Connectors - clean/repair as necessary.
Is any Terminal damaged, pushed out, or miswired?All
Ye s®Clean or repair connector as necessary.
Perform Powertrain Verification Test VER-5A.
No®Go To 4
51
DRIVEABILITY
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Symptom:
P-0131 1/1 O2 SENSOR VOLTAGE SHORTED TO GROUND
When Monitored and Set Condition:
P-0131 1/1 O2 SENSOR VOLTAGE SHORTED TO GROUND
When Monitored: With the ignition key off, after the O2 Sensor cools down; and after the
next key on provided that it is a cold start (coolant temperature less than 38 degrees C
(100.4 degrees F)) and ambient temperature within 13 degrees C (7.2 degrees F) of coolant
temperature.
Set Condition: The upstream O2 Sensor Signal voltage is below 0.156 volt prior to O2
Sensor Heater test (cool down period), and O2 voltage less than 0.156 volt after the key on
in the subsequent start.
POSSIBLE CAUSES
1/1 02 SENSOR VOLTAGE LOW
1/1 O2S SIGNAL CIRCUIT SHORT TO GROUND
1/1 O2S SIGNAL CKT SHORT TO GROUND CIRCUIT
1/1 O2 SENSOR DEFECTIVE
PCM DEFECTIVE (1/1 O2S)
TEST ACTION APPLICABILITY
1 Ignition Off
Turn ignition on.
With the DRB, monitor the Upstream O2 Sensor voltage for a few minutes.
Wait three minutes or until the voltage stabilizes (between 0.4 and 0.6 volt).
With the DRB, monitor the Upstream O2 Sensor voltage.
Is the Upstream O2 Sensor voltage below 0.156 volt?All
Ye s®Go To 2
No®The condition required to set this trouble code is not present at
this time.
Perform Powertrain Verification Test VER-5A.
2 Ignition Off
Disconnect the Upstream O2 Sensor Connector.
Note: Check connectors - Clean/repair as necessary.
Key on.
With the DRB, monitor the Upstream O2 Sensor voltage.
Is the Upstream O2 Sensor voltage below 0.156 volts?All
Ye s®Go To 3
No®Replace the Upstream O2 Sensor.
Perform Powertrain Verification Test VER-5A.
53
DRIVEABILITY
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Symptom:
P-0132 1/1 O2 SENSOR SHORTED TO VOLTAGE
When Monitored and Set Condition:
P-0132 1/1 O2 SENSOR SHORTED TO VOLTAGE
When Monitored: With the engine running for more than 2 minutes and coolant
temperature above 76 degrees C (170 degrees F).
Set Condition: The Upstream Oxygen Sensor Signal voltage is above 1.2 volts.
POSSIBLE CAUSES
1/1 O2 SENSOR SIGNAL CIRCUIT SHORT TO VOLTAGE
1/1 O2 SEN HARNESS INTERMITTENT SHORT TO VOLTAGE
1/1 O2 SENSOR CONNECTOR OBSERVABLE DEFECT (A)
1/1 O2 SENSOR CONNECTOR OBSERVABLE DEFECT (B)
1/1 O2 SENSOR HARNESS OBSERVABLE DEFECT
1/1 O2 SENSOR DEFECTIVE
TEST ACTION APPLICABILITY
1 Start the engine.
With the DRB, read the Upstream O2 Sensor voltage.
Is the Upstream O2 Sensor voltage above 1.2 volts?All
Ye s®Go To 2
No®Go To 5
2 Ignition Off
Disconnect the Upstream O2 Sensor.
Note: Check connectors - Clean/repair as necessary.
Start the engine.
With the DRB, read the Upstream O2 Sensor Voltage.
Is the Upstream O2 Sensor voltage above 1.2 volts?All
Ye s®Repair the Upstream O2 Sensor Signal Circuit for a short to
voltage. If ok, replace the PCM.
Perform Powertrain Verification Test VER-5A.
No®Go To 3
3 Ignition Off
Disconnect the Upstream O2 Sensor.
Note: Check connectors - Clean/repair as necessary.
Is any Terminal damaged, pushed out or miswired?All
Ye s®Repair or replace as necessary.
Perform Powertrain Verification Test VER-5A.
No®Go To 4
55
DRIVEABILITY
ProCarManuals.com
Symptom:
P-0137 1/2 O2 SENSOR VOLTAGE SHORTED TO GROUND
When Monitored and Set Condition:
P-0137 1/2 O2 SENSOR VOLTAGE SHORTED TO GROUND
When Monitored: With the ignition key off, after the O2 Sensor cools down; and after the
next key on provided that it is a cold start (coolant temperature less than 38 degrees C
(100.4 degrees F) and ambient temperature within 13.7 degrees C (7.2 degrees F) of coolant
temperature.
Set Condition: The Downstream O2 Sensor Signal voltage is below 0.156 volt prior to O2
Sensor Heater test (cool down period), and O2 voltage less than 0.156 volt after the key on
in the subsequent start.
POSSIBLE CAUSES
1/2 02 SENSOR VOLTAGE LOW
1/2 O2S SIGNAL CIRCUIT SHORT TO GROUND
1/2 O2S SIGNAL CKT SHORT TO GROUND CIRCUIT
1/2 O2 SENSOR DEFECTIVE
PCM DEFECTIVE (1/2 O2S)
TEST ACTION APPLICABILITY
1 Ignition Off
Turn ignition on.
With the DRB, monitor the Downstream O2 Sensor voltage for a few minutes.
Wait three minutes or until the voltage stabilizes (between 0.4 and 0.6 volt).
With the DRB, monitor the Downstream O2 Sensor voltage.
Is the Downstream O2 Sensor voltage below 0.156 volt?All
Ye s®Go To 2
No®The condition required to set this trouble code is not present at
this time.
Perform Powertrain Verification Test VER-5A.
2 Ignition Off
Disconnect the Downstream O2 Sensor Connector.
Note: Check connectors - Clean/repair as necessary.
Key on.
With the DRB, monitor the Downstream O2 Sensor voltage.
Is the Downstream O2 Sensor voltage below 0.156 volts?All
Ye s®Go To 3
No®Replace the Downstream O2 Sensor.
Perform Powertrain Verification Test VER-5A.
64
DRIVEABILITY
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Symptom:
P-0138 1/2 O2 SENSOR SHORTED TO VOLTAGE
When Monitored and Set Condition:
P-0138 1/2 O2 SENSOR SHORTED TO VOLTAGE
When Monitored: With the engine running for more than 2 minutes and coolant
temperature above 76 degrees C (170 degrees F).
Set Condition: The Downstream Oxygen Sensor Signal voltage is above 1.2 volts.
POSSIBLE CAUSES
1/2 O2 SENSOR SIGNAL CIRCUIT SHORT TO VOLTAGE
1/2 O2 SEN HARNESS INTERMITTENT SHORT TO VOLTAGE
1/2 O2 SENSOR CONNECTOR OBSERVABLE DEFECT (A)
1/2 O2 SENSOR CONNECTOR OBSERVABLE DEFECT (B)
1/2 O2 SENSOR HARNESS OBSERVABLE DEFECT
1/2 O2 SENSOR DEFECTIVE
TEST ACTION APPLICABILITY
1 Start the engine.
With the DRB, read the Downstream O2 Sensor voltage.
Is the Downstream O2 Sensor voltage above 1.2 volts?All
Ye s®Go To 2
No®Go To 5
2 Ignition Off
Disconnect the Downstream O2 Sensor.
Note: Check connectors - Clean/repair as necessary.
Start the engine.
With the DRB, read the Downstream O2 Sensor Voltage.
Is the Upstream O2 Sensor voltage above 1.2 volts?All
Ye s®Repair the Downstream O2 Sensor Signal Circuit for a short to
voltage. If ok, replace the PCM.
Perform Powertrain Verification Test VER-5A.
No®Go To 3
3 Ignition Off
Disconnect the Downstream O2 Sensor.
Note: Check connectors - Clean/repair as necessary.
Is any Terminal damaged, pushed out or miswired?All
Ye s®Repair or replace as necessary.
Perform Powertrain Verification Test VER-5A.
No®Go To 4
66
DRIVEABILITY
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TEST ACTION APPLICABILITY
3 Ignition On, Engine Not Running.
With the DRB, read TPS Sensor voltage. Throttle must be against stop.
Is the voltage 0.92 or less with the Throttle closed?All
Ye s®Go To 4
No®Replace the Throttle Position Sensor.
Perform Powertrain Verification Test VER-5A.
4 Turn ignition On.
With the DRB in sensors, read the ªEngine Coolant Tmp Degº value.
Note: If engine coolant temperature is above 82ÉC (180ÉF), allow the engine
to cool until 62ÉC (150ÉF) is reached.
Start the Engine.
While monitoring the DRB, allow the engine to reach normal operating temperature
above 82ÉC (180ÉF).
Did the engine coolant temperature value reach 82ÉC (180ÉF) or above?All
Ye s®Go To 5
No®Replace the Engine Coolant Temperature Sensor.
Perform Powertrain Verification Test VER-5A.
5 Turn ignition On.
With the DRB in sensors, read the88Eng Coolant Tmp Deg'' value
Note: If engine coolant temperature is above 82ÉC (180ÉF), allow the engine
to cool until 62ÉC (150ÉF) is reached.
Start the Engine.
While monitoring the DRB, allow the engine to reach normal operating temperature
above 82ÉC (180ÉF).
Was the coolant temperature value increase a smooth transition?All
Ye s®Go To 6
No®Replace the Engine Coolant Temperature Sensor.
Perform Verificatino Test VER-5A.
6 Turn ignition off.
Connect a Vacuum Gauge to a Manifold Vacuum source.
Start the engine.
Allow the engine to idle.
Note: If engine will not idle, maintain a constant RPM above idle.
Using the DRB in Sensors, read the MAP Sensor vacuum value.
Is the DRB reading within 19of the Vacuum Gauge reading?All
Ye s®Go To 7
No®Replace the MAP Sensor.
Perform Powertrain Verification Test VER-5A.
76
DRIVEABILITY
P-0171±1/1 FUEL SYSTEM LEAN ÐContinued
ProCarManuals.com
TEST ACTION APPLICABILITY
3 Ignition On, Engine Not Running.
With the DRB, read TP Sensor voltage. Throttle must be against stop.
Is the voltage 0.92 or less with the Throttle closed?All
Ye s®Go To 4
No®Replace the Throttle Position Sensor.
Perform Powertrain Verification Test VER-5A.
4 Turn ignition on.
With the DRB in sensors, read the ªEng Coolant Tmp Degº value.
Note: If engine coolant temperature is above 82ÉC (180ÉF), allow the engine
to cool until 62ÉC (150ÉF) is reached.
Start the Engine.
While monitoring the DRB, allow the engine to reach normal operating temperature
above 82ÉC (180ÉF).
Did the engine coolant temperature value reach 180ÉF or above?All
Ye s®Go To 5
No®Replace the Engine Coolant Temperature Sensor.
Perform Powertrain Verification Test VER-5A.
5 Turn ignition On.
With the DRB in sensors, read the ªEng Coolant Tmp Deg'' value
Note: If engine coolant temperature is above 82ÉC (180ÉF), allow the engine
to cool until 62ÉC (150ÉF) is reached.
Start the Engine.
While monitoring the DRB, allow the engine to reach normal operating temperature
above 82ÉC (180ÉF).
Was the coolant temperature value increase a smooth transition?All
Ye s®Go To 6
No®Replace the Engine Coolant Temperature Sensor.
Perform Verification Test VER-5A.
6 Turn ignition off.
Connect a Vacuum Gauge to a Manifold Vacuum source.
Start the engine.
Allow the engine to idle.
Note: If engine will not idle, maintain a constant RPM above idle.
Using the DRB in Sensors, read the MAP Sensor vacuum value.
Is the DRB reading within 19of the Vacuum Gauge reading?All
Ye s®Go To 7
No®Replace the MAP Sensor.
Perform Powertrain Verification Test VER-5A.
7Note: Engine must be at operating temp and in closed loop to perform this
test.
Start engine and run until operating temp and closed loop mode is reached.
With the DRB under System Tests, go to ªPurge Vapors Test''. Observe the Short
Term Adaptive value and press 3 to flow.
Note: Short Term Adaptive should change.
Did the Short Term Adaptive value change?All
Ye s®Go To 8
No®Refer to symptom *CHECKING EVAPORATIVE EMISSION
SYSTEM in the DRIVEABILITY category.
80
P0172 -1/1 FUEL SYSTEM RICH ÐContinued
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