Diagnostic Test
- ACTIVE DTC
- Turn the ignition on.
- With the scan tool, read DTCs. Record DTC and Freeze Frame information.
- Start the engine and test drive the vehicle long enough for the O2 Sensor to enter closed loop operation.
- With the scan tool, read the active DTCs.
Is the DTC Active at this time?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
- CHECK THE (K141) O2 SENSOR 1/2 SIGNAL CIRCUIT FOR A SHORT TO GROUND
- Turn the ignition off.
- Disconnect the Oxygen Sensor 1/2 harness connector.
- Disconnect the PCM C2 harness connector.
- Measure the resistance between ground and the (K141) O2 Sensor 1/2 Signal circuit in the Oxygen Sensor 1/2 harness connector.
Is the resistance below 10k Ohms?
Yes
- Repair the (K141) O2 Sensor 1/2 Signal circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 3
- CHECK FOR THE (K141) O2 SENSOR 1/2 SIGNAL CIRCUIT SHORTED TO THE (K904) O2 SENSOR 1/2 RETURN CIRCUIT
- Measure the resistance between the (K141) O2 Sensor 1/2 Signal circuit and the (K904) O2 Sensor 1/2 Return circuit in the Oxygen Sensor 1/2 harness connector.
Is the resistance below 10k Ohms?
Yes
- Repair the short between the (K904) O2 Sensor 1/2 Return circuit and the (K141) O2 Sensor 1/2 Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 4
- Measure the resistance between the (K141) O2 Sensor 1/2 Signal circuit and the (K904) O2 Sensor 1/2 Return circuit in the Oxygen Sensor 1/2 harness connector.
- CHECK FOR THE (K141) O2 SENSOR 1/2 SIGNAL CIRCUIT SHORTED TO THE (Z904) GROUND CIRCUIT
- Measure the resistance between the (K141) O2 Sensor 1/2 Signal circuit and the (Z904) Ground circuit in the Oxygen Sensor 1/2 harness connector.
Is the resistance below 10k Ohms?
Yes
- Repair the short between the (Z904) Ground circuit and the (K141) O2 Sensor 1/2 Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 5
- Measure the resistance between the (K141) O2 Sensor 1/2 Signal circuit and the (Z904) Ground circuit in the Oxygen Sensor 1/2 harness connector.
- O2 SENSOR 1/2
- Reconnect the Oxygen Sensor 1/2 harness connector.
- Reconnect the PCM C2 harness connector.
- Turn the ignition on.
- With the scan tool erase DTCs.
- Turn the ignition off.
- Disconnect the Oxygen Sensor 1/2 harness connector.
- Connect a jumper between the (K141) O2 Sensor 1/2 Signal circuit and the (Z904) Ground circuit.
- Start the engine and allow it to idle.
- With the scan tool, view DTCs.
Does the P0138-O2 SENSOR 1/2 CIRCUIT HIGH DTC become active or pending with the jumper in place?
Yes
- Replace the O2 Sensor in accordance with the service information. Refer to SENSOR, OXYGEN, REMOVAL .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 6
- POWERTRAIN CONTROL MODULE (PCM)
- Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Oxygen Sensor 1/2 and the Powertrain Control Module (PCM).
- Look for any chafed, pierced, pinched or partially broken wires. Verify that there is good pin to terminal contact in the O2 Sensor and Powertrain Control Module harness connectors.
- Look for broken, bent, pushed out or corroded terminals.
- Perform any Technical Service Bulletins (TSBs) that may apply.
Were any problems found?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Replace and program the Powertrain Control Module (PCM) in accordance with the service information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .