Engine Oil Pressure Indicator Always On

Engine Oil Pressure Indicator Always On

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The engine oil pressure (EOP) switch is a normally closed switch that opens with the proper oil pressure. With the ignition switch turned ON and the engine not running, the engine control module (ECM) should detect a low signal voltage input. With the engine running, the pressure switch opens, and the ECM should detect a high signal voltage input. The ECM tests the state of the EOP circuit with the ignition switch turned ON, and the engine turned OFF. If the ECM detects a high voltage input on the EOP signal circuit, DTC P1189 will set.

Circuit/System Testing

1. Ignition ON, engine ON, verify the scan tool Engine Oil Pressure Switch parameter is Low.

• If not Low, replace the instrument panel cluster (IPC).

2. Ignition OFF, disconnect the EOP switch.
3. Ignition ON, verify the scan tool Engine Oil Pressure Switch parameter is Ok.

• If not OK, test the signal circuit of the EOP switch for a short to ground. If the circuit tests normal, refer to Oil Pressure Diagnosis and Testing for the 2.2L engine or Oil Pressure Diagnosis and Testing for the 2.4L engine. If the pressure is normal, replace the ECM. Testing and Inspection

4. If all circuits test normal, test or replace the EOP switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

* Engine Oil Pressure Sensor and/or Switch Replacement for the 2.2L engine
* Engine Oil Pressure Sensor and/or Switch Replacement for the 2.4L engine
* Control Module References for PCM and IPC replacement, setup, and programming Verification Tests