P0141
CIRCUIT DESCRIPTIONEngine Control Schematics: Heated Oxygen Sensors (HO2S):
The oxygen sensor heater is a device used to reduce the time that the sensor takes to go active. The bank 1 sensor 2 heater helps to maintain the sensor at the proper temperature for catalyst testing, and additional adjustments to fuel trim. The bank 1 sensor 2 heater receives power through a fused ignition circuit. The PCM turns the heater ON, and OFF using a low side driver (ODM) located within the PCM.
The PCM will test the heater only after a cold start. The PCM determines a cold start based on the difference between the ECT at the last key OFF, and the ECT at the current key ON. During the heater test, the PCM monitors the H02 sensor voltage. When the H02 sensor voltage indicates a sufficiently active sensor, the PCM looks at how much time has elapsed since start-up. If the PCM determines that too much time was required for the sensor to become active, DTC P0141 will set. The amount of time for the sensor to reach operating temperature is based on the ECT at start-up and the average mass air flow since start-up (more airflow and/or higher start-up ECT results in a shorter time to sensor activity).
CONDITIONS FOR RUNNING THE DTC
^ No HO2S bank 1 sensor 2 DTCs are set
^ The difference between ECT at last key OFF and the current key ON indicates a cold start.
^ System voltage is between 10 and 18 volts.
^ Average MAF is less than 30 g/s.
CONDITIONS FOR SETTING THE DTC
The HO2S bank 1 sensor 2 voltage remains within 150 mV of the bias voltage (approximately 450 mV) for a longer amount of time than expected. The amount of time ranges from 94 to 200 seconds depending on the ECT at start-up and the average MAF since start-up.
ACTION TAKEN WHEN THE DTC SETS
^ The PCM will illuminate the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the diagnostic has been run and failed.
^ The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records.
CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
^ The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using the scan tool Clear DTC Information function.
DIAGNOSTIC AIDS
NOTE: Refer to Connector Test Adapter Kit J 35616-A Notice in Service Precautions.
If the condition is intermiffent, refer to Intermittent Conditions in Symptoms. Intermittent Conditions
TEST DESCRIPTION
