P0137

P0137-O2 SENSOR 1/2 CIRCUIT LOW





For a complete wiring diagram REFER to DIAGRAMS/ELECTRICAL .


- When Monitored:
With the engine running for less than 30 seconds, the 1/2 Oxygen Sensor heater temperature less than 251 C (484 F), and battery voltage greater than 10 volts.

- Set Condition:
The PCM detects that the 1/2 Oxygen Sensor signal voltage is below 2.5196 volts for 6 seconds after engine startup. One Trip Fault. Three good trips to turn off the MIL.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.Initial Inspection and Diagnostic Overview.


Diagnostic Test


1. DTC IS ACTIVE
Turn the ignition on.
With a scan tool, select View DTCs. Record DTC and Freeze Frame information.
Start the engine and allow it to idle for at least 60 seconds.

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

With a scan tool, select View DTCs.
Is the status Active for this DTC?

Yes


- Go to 2


No


- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.Checking For An Intermittent DTC


2. (K141) O2 1/2 SIGNAL CIRCUIT VOLTAGE
Turn the ignition off.
Disconnect the 1/2 Oxygen Sensor harness connector.
Turn the ignition on.
With a scan tool, monitor the 1/2 Oxygen Sensor Volts.
Is the voltage above 4.8 volts?

Yes


- Go to 3


No


- Go to 5


3. 1/2 OXYGEN SENSOR RETURN CIRCUIT VOLTAGE




Measure the voltage on the (K904) O2 1/2 Return circuit in the 1/2 Oxygen Sensor harness connector.
Is the voltage between 2.475 and 2.525 volts?

Yes


- Go to 7


No


- Go to 4


4. (K904) O2 1/2 RETURN CIRCUIT SHORTED TO GROUND




Turn the ignition off.
Disconnect the Powertrain Control Module (PCM) harness connector.
Measure the resistance between ground and the (K904) O2 1/2 Return circuit in the 1/2 Oxygen Sensor harness connector.
Is the resistance below 100 ohms?

Yes


- Repair the (K904) O2 1/2 Return circuit for a short to ground.
- Perform the PCM Verification Test.Powertrain Verification Test


No


- Go to 8


5. (K141) O2 1/2 SIGNAL CIRCUIT SHORTED TO GROUND




Measure the resistance between ground and the (K141) O2 1/2 Signal circuit in the 1/2 Oxygen Sensor harness connector.
Is the resistance below 100 ohms?

Yes


- Repair the (K141) O2 1/2 Signal circuit for a short to ground.
- Perform the PCM Verification Test.Powertrain Verification Test


No


- Go to 6


6. (K141) O2 1/2 SIGNAL CIRCUIT SHORTED TO THE (K904) O2 1/2 RETURN CIRCUIT




Measure the resistance between the (K141) O2 1/2 Signal circuit and the (K904) O2 1/2 Return circuit in the 1/2 Oxygen Sensor harness connector.
Is the resistance below 100 ohms?

Yes


- Repair the short between the (K904) O2 1/2 Return circuit and the (K141) O2 1/2 Signal circuit.
- Perform the PCM Verification Test.Powertrain Verification Test


No


- Go to 8


7. 1/2 OXYGEN SENSOR
Turn the ignition off.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the 1/2 Oxygen Sensor and the Powertrain Control Module (PCM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related connectors.

Were any problems found?

Yes


- Repair as necessary.
- Perform the PCM Verification Test.Powertrain Verification Test


No


- Replace the 1/2 Oxygen Sensor.
- Perform the PCM Verification Test.Powertrain Verification Test


8. POWERTRAIN CONTROL MODULE (PCM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the 1/2 Oxygen Sensor and the Powertrain Control Module (PCM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related connectors.
Refer to any Technical Service Bulletins that may apply.

Were any problems found?

Yes


- Repair as necessary.
- Perform the PCM Verification Test.Powertrain Verification Test


No


- Replace and program the Powertrain Control Module (PCM).
- Perform the PCM Verification Test.Powertrain Verification Test