Diagnostic Test
- ACTIVE DTC
- Start the engine.
- Allow the engine to reach normal operating temperature.
- With a scan tool, View DTCs.
Is the DTC active or pending?
Yes
- Go To 2
No
- Perform the INTERMITTENT DTC diagnostic procedure. Refer to STANDARD PROCEDURE .
- CHECK THE (K902) O2 1/1 RETURN CIRCUIT FOR A SHORT TO GROUND
- Turn the ignition off.
- Disconnect the O2 Sensor 1/1 harness connector.
- Disconnect the PCM C1 harness connector.
- Measure the resistance between ground and the (K902) O2 1/1 Return circuit at the O2 Sensor harness connector.
Is the resistance above 10k Ohms?
Yes
- Go To 3
No
- Repair the (K902) O2 1/1 Return circuit for a short to ground.
- Perform the PCM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
- CHECK THE (K41) O2 SENSOR 1/1 SIGNAL CIRCUIT FOR A SHORT TO GROUND
- Turn the ignition off.
- Disconnect the O2 Sensor 1/1 harness connector.
- Disconnect the PCM C1 harness connector.
- Measure the resistance between ground and the (K41) O2 Sensor 1/1 Signal circuit at the O2 Sensor harness connector.
Is the resistance above 10k Ohms?
Yes
- Go To 4
No
- Repair the (K41) O2 Sensor 1/1 Signal circuit for a short to ground.
- Perform the PCM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
- CHECK FOR THE (K41) O2 SENSOR 1/1 SIGNAL CIRCUIT SHORTED TO THE (K902) O2 1/1 RETURN CIRCUIT
- Measure the resistance between the (K41) O2 Sensor 1/1 Signal circuit and the (K902) O2 1/1 Return circuit in the O2 Sensor harness connector.
Is the resistance below 10K Ohms?
Yes
- Repair the short between the (K902) O2 1/1 Return circuit and the (K41) O2 Sensor 1/1 Signal circuit.
- Perform the PCM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
No
- Go To 5
- Measure the resistance between the (K41) O2 Sensor 1/1 Signal circuit and the (K902) O2 1/1 Return circuit in the O2 Sensor harness connector.
- O2 SENSOR
- Measure the voltage on the (K902) O2 1/1 Return Upstream circuit in the O2 Sensor harness connector.
Is the voltage at 2.5 volts?
Yes
- Replace the O2 Sensor.
- Perform the PCM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
No
- Go To 6
- Measure the voltage on the (K902) O2 1/1 Return Upstream circuit in the O2 Sensor harness connector.
- POWERTRAIN CONTROL MODULE NOTE:
Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
- Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
Were there any problems found?
Yes
- Repair as necessary.
- Perform the PCM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
No
- Replace and program the Powertrain Control Module in accordance with the service information. Refer to STANDARD PROCEDURE .
- Perform the PCM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
- Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.