Circuit Description
The heated oxygen sensor (HO2S) heater is a device used to reduce the time that the HO2S takes to go active. The powertrain control module (PCM) controls the HO2S heaters using low side (ODM) drivers. The PCM uses a current monitoring driver to test the condition of the fuel control heaters. A high side driver provides HO2S bank 1 sensor 1 heater with ignition voltage. A low side driver provides the ground path for both of the heaters. With the engine running, the PCM turns ON the high side, and the low side driver to warm-up the oxygen sensors. If the PCM detects an incorrect circuit condition for the commanded state of the low side driver, this diagnostic trouble code (DTC) will set.
Conditions for Running the DTC
| • | The system voltage is 9-18 volts. |
| • | The ignition in ON. |
Conditions for Setting the DTC
The PCM detects an incorrect circuit condition for the commanded state of the low side driver (warm-up 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 .
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics | |||
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |
2 |
Do DTCs P0030, P1031, and P1032 set? | Go to DTC P0030 | Go to Step 3 |
3 |
Do DTCs P1031 and P1032 set? | Go to Step 4 | Go to Intermittent Conditions |
4 |
Does the test lamp turn ON and OFF? | Go to Step 9 | Go to Step 5 |
5 |
Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury. Does the test lamp turn ON and OFF? | Go to Step 8 | Go to Step 6 |
6 |
Did you find and correct the condition? | Go to Step 11 | Go to Step 7 |
7 | Test the HO2S bank 2 sensor 1 heater low control circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 11 | Go to Step 10 |
8 | Replace HO2S bank 2 sensor 1. Refer to Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 . Did you complete the replacement? | Go to Step 11 | -- |
9 | Replace HO2S bank 1 sensor 1. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 . Did you complete the replacement? | Go to Step 11 | -- |
10 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | Go to Step 11 | -- |
11 |
Does the DTC run and pass? | Go to Step 12 | Go to Step 2 |
12 | With a scan tool observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | System OK | |
