Engine Oil Pressure Indicator Always On 2.4L, 3.5L and 3.6L Engine
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 provide an overview of each diagnostic category. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Engine Oil Pressure Switch Signal Circuit | 1 | P0520 | P0520 | -- |
Engine Oil Pressure Switch Ground Circuit | -- | P0520 | -- | -- |
1. Engine Oil Pressure Indicator Always On | ||||
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. When the oil pressure is low, the ECM sends a serial data message to the body control module (BCM) requesting the EOP indicator turned ON. The instrument panel cluster (IPC) illuminates the EOP indicator when the IPC receives a serial data message from the BCM requesting the EOP indicator turned ON.
Reference Information
Schematic Reference
| • | Engine Controls Schematics for the 2.4L engine |
| • | Engine Controls Schematics for the 3.5L engine |
| • | Engine Controls Schematics for the 3.6L engine |
Connector End View Reference
| • | Engine Control Module Connector End Views for the 2.4L engine |
| • | Engine Control Module Connector End Views for the 3.5L engine |
| • | Engine Control Module Connector End Views for the 3.6L engine |
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
Important: Do not turn the key to the crank position or engage the starter at any time during diagnosis.
- Ignition ON, verify the scan tool Engine Oil Pressure (EOP) Switch parameter is Low.
- Ignition OFF, disconnect the EOP switch.
- Ignition ON, verify the scan tool Engine Oil Pressure Switch parameter is OK.
| ⇒ | If not Low, replace the instrument panel cluster (IPC). |
| ⇒ | If not OK, test the signal circuit of the EOP switch 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 after completing the diagnostic procedure.
| • | Engine Oil Pressure Sensor and/or Switch Replacement for the 3.6L engine |
| • | Engine Oil Pressure Sensor and/or Switch Replacement for the 3.5L engine |
| • | Engine Oil Pressure Sensor and/or Switch Replacement for the 2.4L engine |
| • | Control Module References for the ECM and IPC replacement, setup, and programming |
Engine Oil Pressure Indicator Always On 3.9L Engine
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 provide an overview of each diagnostic category. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
5-Volt Reference Circuit 1 | P0522 | P0522 | -- | P0521 |
Engine Oil Pressure Sensor Signal Circuit | P0522 | P0522 | P0523 | P0521 |
Low Reference | -- | P0523 | -- | P0521 |
Circuit/System Description
The engine oil pressure (EOP) sensor changes voltage based on the engine oil pressure. The EOP sensor is a 3-wire sensor comprising of the signal circuit, the low reference circuit, and the 5-volt reference circuit. The engine control module (ECM) or the powertrain control module (PCM) supplies 5 volts to the EOP sensor via the 5-volt reference circuit and provides ground via the EOP low reference circuit. The ECM/PCM monitors the signal circuit of the EOP sensor to determine the engine oil pressure sensor voltage is within the normal operating range of approximately 1-4 volts. When the engine oil pressure is high, the EOP sensor voltage is high and the ECM/PCM senses a high signal voltage. When the engine oil pressure is low, the EOP sensor voltage is low and the ECM/PCM senses a low signal voltage. The ECM/PCM sends the EOP information to the instrument panel cluster (IPC) via the serial data circuit. The IPC illuminates the engine oil pressure indicator when it receives a serial data message indicating a low engine oil pressure condition.
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
Ignition ON, scan tool installed, perform the Displays Test in the IPC Output Controls Special Functions . Verify that the engine oil pressure (EOP) indicator turns OFF after the Displays Test.
| ⇒ | If the EOP indicator does not turn OFF after the Displays Test, test or replace the IPC. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for IPC replacement, setup and programming |
