P0137

P0137-O2 SENSOR 1/2 CIRCUIT LOW







- When Monitored:
With the engine running for less than 30 seconds, the Oxygen Sensor 1/2 heater temperature less than 251° C (484° F), and battery voltage greater than 10.4 volts.

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





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. OXYGEN SENSOR 1/2 VOLTAGE
1. Start the engine and allow it to reach normal operating temperature.

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 may result in possible serious or fatal injury.

2. With a scan tool, monitor the 1/2 O2 Sensor Volts.

Is the voltage less than 2.52 volts?

Yes

- Go To 2

No

- Perform the CHECKING FOR AN INTERMITTENT DTC diagnostic procedure. Checking for an Intermittent DTC.

2. (K141) O2 1/2 SIGNAL CIRCUIT VOLTAGE
1. Turn the ignition off.
2. Disconnect the Oxygen Sensor 1/2 harness connector.
3. Turn the ignition on.
4. With a scan tool, monitor the 1/2 O2 Sensor Volts.

Is the voltage above 4.8 volts?

Yes

- Go To 3

No

- Go To 5

3. OXYGEN SENSOR 1/2 RETURN CIRCUIT VOLTAGE




1. Measure the voltage on the (K904) O2 1/2 Return circuit in the Oxygen Sensor 1/2 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




1. Turn the ignition off.
2. Disconnect the Powertrain Control Module (PCM) harness connector.
3. Measure the resistance between ground and the (K904) O2 1/2 Return circuit in the Oxygen Sensor 1/2 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. PCM Verification Test.

No

- Go To 8

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




1. Measure the resistance between ground and the (K141) O2 1/2 Signal circuit in the Oxygen Sensor 1/2 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. PCM Verification Test.

No

- Go To 6

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




1. Measure the resistance between the (K141) O2 1/2 Signal circuit and the (K904) O2 1/2 Return circuit in the Oxygen Sensor 1/2 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. PCM Verification Test.

No

- Go To 8

7. OXYGEN SENSOR 1/2
1. Turn the ignition off.
2. Inspect the wiring and connectors between the Oxygen Sensor 1/2 and the Powertrain Control Module (PCM).
3. Look for any chafed, pierced, pinched, or partially broken wires.
4. 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. PCM Verification Test.

No

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

8. POWERTRAIN CONTROL MODULE (PCM)
1. 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).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Perform any Technical Service Bulletins that may apply.

Were any problems found?

Yes

- Repair as necessary.
- Perform the PCM VERIFICATION TEST. PCM Verification Test.

No

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