Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC P2232: HO2S Signal Circuit Shorted to Heater Circuit Sensor 2Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
HO2S 2 Signal | P0137, P2096 | P0140 | P0138, P2232 | -- |
HO2S 2 Low Reference | -- | P0140 | -- | -- |
Circuit Description
The engine control module (ECM) supplies a voltage near 450 mV between the heated oxygen sensor (HO2S) high signal circuit and the low reference circuit. The HO2S varies the voltage over a range from about 1,000 mV when the exhaust is rich, down through about 10 mV when the exhaust is lean.
The ECM monitors and stores the HO2S voltage information. The ECM evaluates the HO2S voltage samples in order to determine the amount of time that the HO2S voltage was out of range. The ECM compares the stored HO2S voltage samples taken within each sample period and determines if the majority of the samples are out of the operating range. This diagnostic detects that the HO2S signal voltage switches at the same rate that the ECM is commanding the HO2S heater.
Conditions for Running the DTC
| • | The engine is operating. |
| • | The ignition voltage is greater than 11 volts. |
| • | The HO2S 2 heater is at operating temperature for greater than 90 seconds. |
| • | DTC P2232 runs continuously once the above conditions are met for greater than 10 seconds. |
Conditions for Setting the DTC
| • | The ECM detects that the HO2S 2 signal voltage increases greater than 2 volts within 40 milliseconds of the HO2S heater switching OFF. |
| • | The above condition occurs 4 times out of 6 as the heater is turned OFF, then 4 seconds or a cumulative of 50 seconds. |
Action Taken when the DTC Sets
DTC P2232 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P2232 is a Type B DTC.
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Diagnostic Aids
The following table illustrates the ECM connector locations:
ECM Connector Location | |
|---|---|
X2 | X1 |
Front of Vehicle | |
The rear HO2S will not go into closed loop when the engine is idling. Once the HO2S are at operating temperature, and the vehicle is moving, the rear HO2S will go into closed loop.
Circuit/System Verification
- Ignition ON, observe the scan tool HO2S 2 voltage parameter. The parameter should display less than 1,050 mV.
- Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the HO2S 2.
- Ignition ON, observe the scan tool HO2S 2 voltage parameter. The parameter should display between 350-550 mV.
- If all circuits test normal, replace the HO2S 2.
| ⇒ | If greater than the specified range, test the high signal circuit for a short to the heater control circuit. If the circuit tests normal, replace the ECM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for engine control module replacement, setup, and programming |
