Circuit Description
Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The engine control module (ECM) supplies the HO2S with a reference, or bias, voltage of about 450 mV. When the engine is first started the ECM operates in Open Loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and Closed Loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream. low HO2S voltage indicates a lean exhaust stream. If the ECM detects an HO2S voltage that stays above a specified value, DTC P0132 sets for HO2S bank 1 sensor 1, or DTC P0152 sets for HO2S bank 2 sensor 1.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC P0132 HO2S Circuit High Voltage Bank 1 Sensor 1 |
| • | DTC P0152 HO2S Circuit High Voltage Bank 2 Sensor 1 |
Conditions for Running the DTC
Rich Test Enable
| • | DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0442, P0443, P0446, P0449, P0455, P0496, P1258, P1516, P2101, P2135, P2176 are not set. |
| • | The Loop Status parameter is closed. |
| • | The Ignition 1 Signal parameter is between 10-18 volts. |
| • | The Fuel Tank Level Remaining parameter is more than 10 percent. |
| • | The TP Indicated Angle parameter is between 3-70 percent more than the value observed at idle. |
| • | The above conditions are met for 2 seconds. |
| • | This diagnostic runs continuously when the above conditions are met. |
Decel Fuel Cutoff Test Enable
| • | DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0442, P0443, P0446, P0449, P0455, P0496, P1258, P1516, P2101, P2135, P2176 are not set. |
| • | The Loop Status parameter is closed. |
| • | The Ignition 1 Signal parameter is between 10-18 volts. |
| • | The Fuel Tank Level Remaining parameter is more than 10 percent. |
| • | The Engine Run Time parameter is more than 30 seconds. |
| • | The Decel Fuel Cutoff parameter is active for more than 2 seconds. |
| • | This diagnostic runs continuously when the above conditions are met. |
Conditions for Setting the DTC
Rich Test
The ECM detects that the affected HO2S voltage parameter is more than 1,050 mV for 48 seconds.
Decel Fuel Cutoff Test
The ECM detects that the affected HO2S voltage parameter is more than 540 mV for 5 seconds.
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. |
| • | The control module commands the Loop Status open. |
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 Description
The number below refers to the step number on the diagnostic table.
Step | Action | Value(s) | Yes | No | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module Connector End Views | ||||||||||||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||||||||||||
Is the HO2S voltage parameter varying above and below the specified range? | 300-600 mV | Go to Step 3 | Go to Step 4 | |||||||||||||||||
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Testing for Intermittent Conditions and Poor Connections | ||||||||||||||||
4 |
Is the HO2S voltage parameter within the specified range? | 400-500 mV | Go to Step 5 | Go to Step 6 | ||||||||||||||||
5 |
Is the HO2S voltage parameter less than the specified value? | 100 mV | Go to Step 7 | Go to Step 8 | ||||||||||||||||
6 | Test the HO2S high signal circuit for a short to the HO2S heater low control circuit. Refer to the : Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 10 | ||||||||||||||||
7 |
Is the HO2S voltage parameter less than the specified value? | 100 mV | Go to Step 9 | Go to Step 11 | ||||||||||||||||
8 | Test the HO2S high signal circuit for an open or high resistance. Refer to the following: Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 14 | ||||||||||||||||
9 | Test the HO2S low signal circuit for a short to the HO2S heater low control circuit. Refer to the following: Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 12 | ||||||||||||||||
10 |
Important: The sensor may be damaged if the circuit is shorted to a voltage source. Test the HO2S high signal circuit for a short to voltage. Refer to the following: Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 14 | ||||||||||||||||
11 | Test the HO2S low signal circuit for an open or high resistance. Refer to the following: Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 14 | ||||||||||||||||
12 |
Notice: Refer to Silicon Contamination of Heated Oxygen Sensors Notice in the Preface section.
Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 13 | ||||||||||||||||
13 | Test for shorted terminals and for poor connections at the HO2S. Refer to the following: Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 15 | ||||||||||||||||
14 | Test for shorted terminals and for poor connections at the engine control module (ECM). Refer to the following: Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 16 | ||||||||||||||||
15 | Replace the affected HO2S. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 or Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 . Did you complete the replacement? | -- | Go to Step 17 | -- | ||||||||||||||||
16 | Replace the ECM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 17 | -- | ||||||||||||||||
17 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 18 | ||||||||||||||||
18 | In order to ensure that the performance of the catalyst has not been affected by the fault that set this DTC, operate the vehicle within the conditions for running and setting DTC P0420 or P0430 and verify that P0420 or P0430 runs and passes. Refer to DTC P0420 or P0430 . Does the DTC run and pass? | -- | Go to Step 19 | Go to DTC P0420 or P0430 | ||||||||||||||||
19 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||||||||||||||
