DTC P0135: 1/1 O2 SENSOR HEATER FAILURE, DTC P0141: 1/2 O2 SENSOR HEATER FAILURE,
DTC P0147: 1/3 O2 SENSOR HEATER FAILURE, DTC P0155: 2/1 O2 SENSOR HEATER FAILURE
OR DTC P0161: 2/2 O2 SENSOR HEATER FAILURE
Monitor & Set Conditions
Heated Oxygen Sensor (HO2S) heaters are monitored when battery voltage is greater than 9 volts, at a cold start, engine coolant temperature is less than 147°F (64°C), battery temperature is within 27°F of engine temperature and engine has been idling for at least 12 seconds. DTCs P0135, P0147 and P0155 will be stored in Powertrain Control Module (PCM) if HO2S voltage is greater than 3 volts for 30-90 seconds. DTCs P0141 and P0161 will be stored in Powertrain Control Module (PCM) if HO2S voltage is greater than 3 volts for 60-240 seconds.
Possible Causes
Intermittent Condition
O2 Heater Element
O2 Sensor Heater Feed Circuit Open
O2 Sensor Heater Ground Circuit Open
O2 Sensor Heater Control Circuit Shorted To Ground
PCM
Testing
1. Turn the ignition off. Wait a minimum of 8 minutes to allow the O2 Sensor to cool down before continuing the test. Turn ignition on, engine not running. Using the DRBIII(R), actuate the O2 Heater test. Using the DRBIII(R), monitor O2 Sensor voltage for at least 2 minutes. Does the voltage stabilize between 0.4 and 0.6 volt during the O2 Heater test? If yes, go to next step. If no, go to step 3 .
2. The conditions that set the DTC are not present at this time. With the engine running at normal operating temperature, monitor the DRBIII(R) parameters related to the DTC while wiggling the wiring harness. Look for parameter values to change and/or a DTC to set. Review the DRBIII(R) Freeze Frame information. If possible, try to duplicate the conditions under which the DTC was set. Refer to any Technical Service Bulletins (TSB) that may apply. Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires. Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals. Were any of the above conditions present? If yes, repair as necessary. If no, test is complete.
3. Turn the ignition off. Allow the O2 Sensor to cool to room temperature. Disconnect the O2 Sensor harness connector for sensor that applies to the specific DTC. Measure the resistance of the O2 Sensor Heater element at the O2 Sensor connector (component side). See HEATED OXYGEN SENSOR
HEATER ELEMENT RESISTANCE table. Is the resistance within specifications? If yes, go to next step. If no, replace the O2 Sensor.
4. The O2 Sensor Heater Feed circuit may be a fused ASD Relay Output or an O2 Sensor Relay output, depending on the O2 Sensor being tested. Turn ignition on, engine not running. Using the DRBIII(R), actuate the O2 Heater test. Measure the voltage on the O2 Sensor Heater Feed circuit. Is the voltage greater than 11.0 volts? If yes, go to next step. If no, repair the open in the O2 Sensor Heater Feed circuit.
5. There are two types of O2 Sensor Heater Ground circuits used on this vehicle. O2 Sensor Heater Ground circuit may be controlled by the PCM or connected to chassis ground. Verify which type applies to the O2 Sensor being tested. See WIRING DIAGRAMS article. For O2 Sensor Heater Ground circuit (O2
Sensor Heater Control circuit) that is PCM controlled, go to next step. For O2 Sensor Heater Ground circuit that uses chassis ground, go to step 7 .
6. On models with PCM controlled O2 Sensor Heater Ground circuit, turn ignition off. Disconnect PCM harness connectors. PCM is located at passenger's side rear corner of engine compartment. Measure the resistance of the O2 Sensor Heater Ground circuit from the O2 Sensor harness connector to the PCM
harness connector. Is the resistance less than 5.0 ohms? If yes, go to step 8 . If no, repair the open or high resistance in the O2 Sensor Heater Ground circuit.
7. On models that use chassis ground for the O2 Sensor Heater Ground circuit, measure resistance between ground and sensor ground circuit at O2 Sensor harness connector. Is resistance less than 5 ohms? If yes, go to step 9 . If no, repair open or high resistance in the O2 Sensor Heater Ground circuit.
8. Measure resistance between ground and the O2 Sensor Ground circuit at the O2 Sensor harness connector. Is the resistance less than 100 ohms? If yes, repair short to ground in the O2 Sensor Heater Ground circuit. If no, go to next step.
9. Replace and program the Powertrain Control Module.