P1031

CIRCUIT DESCRIPTION
Heating elements inside the heated oxygen sensors (HO2S) minimize the time required for the sensors to reach operating temperature, and to provide an accurate voltage signal. The powertrain control module (PCM) controls the HO2S 1 heaters using low side drivers. The PCM uses a current monitoring driver to test the condition of the HO2S 1 heaters. A high side driver provides HO2S bank 1 sensor 1 heater with ignition voltage. The bank 2 HO2S 1 is supplied power from the external ignition 1 voltage circuit. With the engine running, the PCM turns ON the high side, and the low side drivers to warm-up the oxygen sensors. If the PCM detects an incorrect circuit condition for the low side drivers, DTC P1031 or P1032 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 current monitor 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.

TEST

Steps 1-4:

Steps 5-8:

Steps 9-15: