Circuit Description
The heated oxygen sensor (HO2S) heater is a device used to reduce the time that the sensor takes to go active. The powertrain control module (PCM) uses a high side driver in order to apply ignition voltage to the bank 1 sensor 1 heater, and uses a low side driver (ODM) in order to supply the ground path. The PCM monitors the high side driver for circuit conditions that are incorrect for the commanded state of the driver. If the PCM detects an improper circuit condition in the high side driver, the diagnostic trouble code (DTC) will set.
Conditions for Running the DTC
The system voltage is between 9-18 volts.
Conditions for Setting the DTC
The PCM detects an incorrect circuit condition in the high side driver for HO2S bank 1 sensor 1.
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
Notice: Use the connector test adapter kit J 35616-A for any test that
requires probing the following items:
• The PCM harness connectors • The electrical center fuse/relay cavities • The component terminals • The component harness connector
If the condition is intermittent, refer to Intermittent Conditions in Symptoms.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step isolates the condition. If all DTCs are set, one of the heater low circuits is grounded. An internal HO2S condition can also cause all DTCs to set.
-
This step determines if the bank 1 sensor 1 heater high circuit is shorted to a ground.
-
The bank 1 sensor 1 and the bank 2 sensor 1 are internally connected within the PCM. If the voltage measurement is within the specified range, the bank 2 sensor 1 is causing the condition.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
2 |
Are all 4 DTCs set? | -- | Go to Step 11 | Go to Step 3 |
Did DTC P0030, P1031, or P1032 set? | -- | Go to Step 7 | Go to Step 4 | |
Is DTC P0030 set? | -- | Go to Step 5 | Go to Intermittent Conditions | |
5 |
Is the voltage more than the specified value? | 10 V | Go to Step 15 | Go to Step 6 |
6 |
Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 17 |
7 |
Is the voltage more than the specified value? | 10 V | Go to Step 15 | Go to Step 8 |
Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury. Is the voltage within the specified range? | 1.2-1.7 V | Go to Step 14 | Go to Step 9 | |
9 |
Did you find and correct the condition? | Go to Step 18 | Go to Step 10 | |
10 | Test the HO2S bank 2 sensor 1 heater low control circuit for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 17 |
11 |
Does the test lamp turn OFF? | -- | Go to Step 14 | Go to Step 12 |
12 | Observe the test lamp as you disconnect the HO2S bank 1 sensor 2 harness connector. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 . Does the test lamp turn OFF? | -- | Go to Step 16 | Go to Step 13 |
13 | Repair the short to ground in the ignition 1 voltage circuit to the HO2S sensors. Did you complete the repair? | -- | Go to Step 18 | -- |
14 | Replace HO2S bank 2 sensor 1. Refer to Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 . Did you complete the replacement? | -- | Go to Step 18 | -- |
15 | Replace HO2S bank 1 sensor 1. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 . Did you complete the replacement? | -- | Go to Step 18 | -- |
16 | Replace HO2S bank 1 sensor 2. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 . Did you complete the replacement? | -- | Go to Step 18 | -- |
17 | Replace the PCM. Refer Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 18 | -- |
18 |
Does the DTC run and pass? | -- | Go to Step 19 | Go to Step 2 |
19 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
