Refer to Engine Controls Schematics
HO2S
.
Circuit Description
The oxygen sensor heater is a device used to reduce the time that the sensor takes to go active. The PCM controls the fuel control oxygen sensor heaters using three separate drivers. With the engine running, the PCM turns ON the heaters using a high side, and a low side driver. This helps warm-up the oxygen sensors. The PCM uses a third driver to test the oxygen sensor heaters. This driver contains current monitoring circuitry, when used in a diagnostic sequence with the other drivers, indicates the condition of the heaters. The PCM monitors this driver for circuit conditions that are incorrect for the commanded state of the driver. If the PCM detects an incorrect circuit condition, DTC P1031 will set.
Conditions for Running the DTC
System voltage is between 9 and 18 volts.
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 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
If the condition is intermittent, refer to Intermittent Conditions .
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
2 |
Are DTCs P0030, P0036, P1031, and/or P1032 set? | -- | ||
3 | Start the engine. Monitor the scan tool Specific DTC Information for 2 minutes. Is DTC P0135 and/or DTC P0155 set? | -- | Go to DTC P0135 HO2S Heater Performance Bank 1 Sensor 1 or DTC P0155 HO2S Heater Performance Bank 2 Sensor 1 | Go to Diagnostic Aids |
