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.

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Oil Pressure Indicator Control | 2 | 1 | -- | --
Oil Pressure Switch Ground | -- | 1 | -- | --
1. Engine Oil Pressure Indicator Inoperative 2. Engine Oil Pressure Indicator Always On

### Circuit Description

The engine oil pressure switch is a normally closed switch that opens with the proper oil pressure. With the ignition switch turned ON and the engine not running, ignition voltage is supplied to the oil pressure indicator, the oil pressure switch will be closed and the indicator will be grounded. With the engine running, the pressure switch opens and the indicator will turn off.

### Reference Information

#### Schematic Reference

Instrument Cluster Schematics

#### Connector End View Reference

Displays and Gages Connector End Views

#### Description and Operation

Instrument Panel Description

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

### Circuit/System Verification

1. Ignition ON, engine OFF, verify the low oil pesewa indicator is ON.
2. Engine running, verify the low oil pressure indicator is OFF.

⇒ | If not the specified value refer to the following:

• | Oil Pressure Diagnosis and Testing

• | Oil Pressure Diagnosis and Testing

• | Oil Pressure Diagnosis and Testing

• | Oil Pressure Diagnosis and Testing

• | Oil Pressure Diagnosis and Testing

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the engine oil pressure switch.
2. Ignition ON, verify the low oil pressure indicator is OFF.

⇒ | If not the specified value, test the indicator control circuit for a short to ground. If the circuit tests normal replace the IPC.

3. Ignition ON, install a 3A fused jumper wire between the indicator control circuit terminal and ground. Verify the low oil pressure indicator is ON.

⇒ | If not the specified value, test the signal circuit for an open/high resistance. If circuit tests normal, replace the low oil pressure indicator bulb.

4. If all circuits test normal, test or replace the engine oil pressure switch.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Instrument Cluster Bulb Replacement

• | Control Module References for IPC replacement, programming, and setup