P0038

P0038-O2 SENSOR 1/2 HEATER CIRCUIT HIGH

Special Tools:










For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The engine after treatment system monitors the oxygen content in the diesel engine exhaust. The Powertrain Control Module (PCM) monitors the exhaust gases for oxygen content and varies the rich/lean fuel mixture of the intake air fuel mixture to adjust the sensor. This diagnostic monitors the status message broadcast by the Smart O2 Sensor Module for the Downstream O2 Sensors internal heater circuit. The PCM will set the fault if it receives an FMI (Failure Mode Indicator) message from the Smart O2 Module. The PCM will illuminate the MIL lamp immediately when the diagnostic runs and fails. The PCM will turn off the MIL lamp diagnostic runs and passes in four consecutive drive cycles.

- When Monitored:
This diagnostic runs when the engine is running.

- Set Condition:
The Powertrain Control Module (PCM) will set the fault if it receives an FMI (Failure Mode Indicator) message from the Smart O2 Module.





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

NOTE: Before replacing any O2 Sensor or O2 Sensor Module, check after treatment wiring harness for spread terminals. For wiring harness checking procedure, DO NOT back probe, use Electric Terminal Tool Kit ( Tool).

1. ACTIVE DTC
1. Turn the ignition on.
2. With the scan tool, record all Freeze frame data.
3. With the scan tool, erase DTCs.
4. Turn the ignition off for 75 seconds.
5. Start the engine and let idle for up to five minutes.
6. With the scan tool, read DTCs.

Did the DTC reset?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test

2. CHECK THE (K80) O2 SENSOR 1/1 HEATER RETURN CIRCUIT FOR A SHORT TO VOLTAGE




1. Turn the engine off.
2. Disconnect the Smart O2 Sensor Module harness connector.
3. Turn the ignition on.
4. Measure the voltage on the (K80) 02 Sensor 1/2 Heater Return circuit at the Smart O2 Sensor Module harness connector.

Is there any voltage present?

Yes

- Repair the (K80) 02 Sensor 1/2 Heater Return circuit for a short to voltage.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 3

3. CHECK THE OXYGEN SENSOR




1. Measure the resistance of the O2 Sensor 1/2 Heater circuit through the O2 Sensor.

Is the resistance 3.2 +/- 0.8 Ohms at ambient temperature?

Yes

- Go To 4

No

- Replace the O2 Sensor.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

4. OXYGEN SENSOR AND O2 SENSOR CONTROL MODULE
1. Remove the O2 Sensor 1/2 and O2 Sensor 1/1. Clean the soot from the sensors.
2. Install the O2 Sensor 1/2 in the O2 Sensor 1/1 position.
3. Install the O2 Sensor 1/1 in the O2 Sensor 1/2 position.
4. With the scan tool, erase DTCs.
5. Turn the ignition off for 75 seconds.
6. Start the engine and let idle for two minutes.
7. With the scan tool, read DTCs.

Did the DTC change to P0032?

Yes

- Reinstall the O2 Sensor 1/1 back to it's original position and replace the O2 Sensor 1/2.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Replace the O2 Sensor Control Module. Return the O2 Sensors back to their original positions.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.