P0038

P0038-O2 SENSOR 1/2 HEATER CIRCUIT HIGH





For a complete wiring diagram Consult Diagrams/Electrical.

- When Monitored:
Battery voltage above 10.6 volts, ASD is powered up, and O2 heater is off.

- Set Condition:
Desired state does not equal Actual state. 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. ACTIVE DTC
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the DTC active at this time?

Yes

- Go To 2

No

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure.Intermittent Condition
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

2. O2 HEATER ELEMENT
Turn the ignition off.

NOTE: Allow the O2 Sensor to cool down to room temperature.

Disconnect the 1/2 O2 Sensor harness connector.
Measure the resistance across the O2 Sensor Heater element, between the Heater Control terminal and the Heater ground terminal at the component.

NOTE: O2 Heater Element resistance values should be measured at 70°F (21.1°C). The resistance value will vary with different temperature values.

Is the O2 Sensor Heater Element resistance between 2.0 and 30.0 ohms?

Yes

- Go To 3

No

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

3. (K299) O2 1/2 HEATER CONTROL CIRCUIT




Ignition on, engine not running.
With a scan tool, actuate the O2 1/2 Heater Test with the O2 Sensor harness connector still disconnected.
Using a 12-volt test light connected to ground, probe the (K299) O2 1/2 Heater Control circuit in the O2 Sensor harness connector.
Does the test light illuminate brightly and flash on and off during the actuation?

Yes

- Go To 4

No

- Go To 5

4. (Z904) O2 HEATER GROUND CIRCUIT OPEN




Turn the ignition off.
Measure the resistance between an engine ground and the (Z904) O2 1/2 Heater ground circuit in the O2 Sensor harness connector.
Is the resistance below 5.0 ohms?

Yes

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

No

- Repair the open in the (Z904) O2 1/2 Heater ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

5. (K299) O2 1/2 HEATER CONTROL CIRCUIT SHORTED TO BATTERY VOLTAGE




Turn the ignition off.
Disconnect the PCM harness connectors.
Ignition on, engine not running.
Measure the voltage on the (K299) O2 1/2 Heater Control circuit in the O2 Sensor harness connector.
Does the voltmeter indicate any voltage present?

Yes

- Repair the short to battery voltage in the (K299) O2 1/2 Heater Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 6

6. (K299) O2 1/2 HEATER CONTROL CIRCUIT OPEN




Turn the ignition off.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of the (K299) O2 1/2 Heater Control circuit from the O2 Sensor harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?

Yes

- Go To 7

No

- Repair the open in the (K299) O2 1/2 Heater Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

7. PCM

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 POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Replace and program the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test