NGC
P0141-O2 SENSOR 1/2 HEATER PERFORMANCE
For a complete wiring diagram Consult Diagrams/Electrical.
- When Monitored:
Continuously during O2 sensor heater operation with battery voltage between 10.4 and 15.75 volts and no O2 sensor circuit DTCs present.
- Set Condition:
The PCM detects no temperature change in the O2 sensor heater element when the heater circuit is active. The heater temperature is obtained by measuring the heater resistance and calculating the heater temperature. Two 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. 1/2 OXYGEN SENSOR HEATER CONTROL OPERATION
NOTE: Allow the sensor to cool to ambient temperature before continuing. The voltage should stabilize between 4.6 and 5.0 volts.
Turn the ignition on.
With a scan tool, actuate the 1/2 Oxygen Sensor heater control.
With the scan tool, monitor the 1/2 Oxygen Sensor voltage for at least 2 minutes.
Does the voltage stay above 4.5 volts?
Yes
- Go to 2
No
- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.Checking For An Intermittent DTC
2. 1/2 OXYGEN SENSOR
Turn the ignition off.
NOTE: Allow the sensor to cool to ambient temperature before continuing. The voltage should stabilize between 4.6 and 5.0 volts.
Disconnect the 1/2 Oxygen Sensor harness connector.
Measure the resistance of the O2 sensor heater element across the 1/2 Oxygen Sensor connector between the heater control terminal and the ground terminal.
NOTE: The resistance of the heater element will vary according to temperature and should be measured at 70° F (21.1° C).
Is the resistance between 2.0 and 30.0 ohms?
Yes
- Go to 3
No
- Replace the 1/2 Oxygen Sensor.
- Perform the PCM Verification Test.Powertrain Verification Test
3. (K299) O2 1/2 HEATER CONTROL CIRCUIT OPEN OR HIGH RESISTANCE
Disconnect the Powertrain Control Module (PCM) harness connector.
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 between the 1/2 Oxygen Sensor harness connector and the appropriate terminal of special tool #8815.
Is the resistance below 0.5 ohms?
Yes
- Go to 4
No
- Repair the (K299) O2 1/2 Heater Control circuit for an open circuit or high resistance.
- Perform the PCM Verification Test.Powertrain Verification Test
4. (Z902) GROUND CIRCUIT OPEN OR HIGH RESISTANCE
Using a 12 volt test light connected to 12 volts, check the (Z902) Ground circuit in the 1/2 Oxygen Sensor harness connector.
NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.
Is the test light illuminated and bright?
Yes
- Go to 5
No
- Repair the (Z902) Ground circuit for an open circuit or high resistance.
- Perform the PCM Verification Test.Powertrain Verification Test
5. 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.
Search for 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