P0036

CIRCUIT DESCRIPTION
The heated oxygen sensor (HO2S) heater is a device used to reduce the time that the sensor takes to go active. The HO2S bank 1 sensor 2 heater helps maintain proper sensor temperature for catalyst testing, and fuel trim adjustments. The heater receives power through a fused ignition circuit. The powertrain control module (PCM) uses a low side driver (ODM) to turn the heater ON and OFF. The PCM monitors the circuit for conditions that are incorrect for the commanded state of the low side driver. If the PCM detects an incorrect circuit conditions, this diagnostic trouble code (DTC) will set.


CONDITIONS FOR RUNNING THE DTC
^ The system voltage is between 9-18 volts.
^ The ignition is ON.

CONDITIONS FOR SETTING THE DTC
The PCM detects an incorrect circuit condition for the commanded state of the low side driver.

ACTION TAKEN WHEN THE DTC SETS
^ The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
^ The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
^ A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
^ Clear the MIL and the DTC with a scan tool.

DIAGNOSTIC AIDS
If the condition is intermittent, refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION

Steps 1-9:

Steps 10-17:

The numbers below refer to the step numbers on the diagnostic table.
2. If the DTC sets with the ignition ON, this indicates the bank 1 sensor 2 heater low circuit is shorted to ground or open. If the HO2S fuse is open, the starter will not engage. Ensure you test all related circuits for a short to ground.
3. If the DTC sets with the engine operating, this indicates the bank 1 sensor 2 heater low circuit 5 shorted to a voltage.
5. An open HO2S fuse causes multiple DTCs to set. If the fuse is open, the starter will not engage. Ensure you test all related circuits for a short to ground.