Engine Oil Pressure Indicator Always On
Engine Oil Pressure Indicator Always On (3.8L L26 and L32)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)provides an overview of each diagnostic category.
Diagnostic Fault Information
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 powertrain control module (PCM) should detect a low signal voltage input. With the engine running, the pressure switch opens, and the PCM should detect a high signal voltage input. The PCM tests the state of the EOP signal circuit with the ignition switch turned ON, and the engine turned OFF. The instrument panel cluster (IPC) illuminates the EOP indicator when the IPC receives a serial data message from the PCM requesting the EOP indicator turned ON.
Reference Information
Schematic Reference
* Instrument Cluster Schematics (Instrument Cluster Schematics)
* Engine Controls Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
* Instrument Cluster Description and Operation (Description and Operation)
* Powertrain Control Module Description (Powertrain Control Module Description)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (Programming and Relearning)for Scan Tool Information
Circuit/System Testing
Important: Do not turn the key to the crank position or engage the starter at any time during diagnosis.
1. Ignition ON, verify the scan tool EOP Switch parameter is Low.
• If not Low, replace the 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 terminal A for a short to ground. If the circuit tests normal, replace the ECM.
• If OK, test or replace the EOP switch.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Engine Oil Pressure Sensor and/or Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning)for the ECM replacement, setup, and programming