For 1990-2009 cars

### 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 Descriptor

DTC P2232: HO2S Signal Circuit Shorted to Heater Circuit Sensor 2

### 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.

### Conditions for Running the DTC

• | The engine is running.

• | The ignition 1 voltage is between 10-18 volts.

• | The DTC runs continuously once the above conditions are met.

### Conditions for Setting the DTC

The ECM detects that the HO2S signal voltage is out of range for greater than 4 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

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Ignition ON, observe the appropriate scan tool HO2S voltage parameter. The reading should be less than 1,050 mV.
2. 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 you observed from the Freeze Frame/Failure Records data.

### Circuit/System Testing

1. Ignition OFF, and the MAIN fuse removed, disconnect the harness connector at the appropriate HO2S.
2. Install the MAIN fuse. Ignition ON, verify the scan tool HO2S parameter is between 350-500 mV.

⇒ | If greater than the specified range, test the signal circuit for a short to the heater circuit. If the circuit tests normal, replace the ECM.

3. If all circuits test normal, test or replace the applicable HO2S.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Heated Oxygen Sensor 2 Replacement

• | Control Module References for engine control module replacement, setup, and programming