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 P0520: Engine Oil Pressure (EOP) Sensor Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Oil Pressure Switch Signal | 1 | P0520 | -- | --
Low Reference Oil Pressure Switch Signal | -- | P0520 | -- | --
1. Engine Oil Pressure Indicator Always On

### Circuit Description

With low oil pressure, the engine oil pressure (EOP) switch closes, and the signal circuit is low. With oil pressure above 4.5 psi, the EOP switch opens, and the signal circuit is high. The powertrain control module (PCM) monitors the oil pressure switch signal circuit, and sends a class 2 message to the instrument panel cluster (IPC), indicating the switch status.

### Conditions for Running the DTC

• | DTC P0117 is not set.

• | DTC P0118 is not set.

• | DTC P1111 is not set.

• | DTC P1114 is not set.

• | The ignition is ON, with the engine OFF.

• | Engine temperature at the last shutdown was at least 80°C (176°F).

### Conditions for Setting the DTC

• | The PCM detects that the oil pressure switch signal circuit is high.

• | The above condition is present for greater than 10 seconds.

### Action Taken When the DTC Sets

The PCM stores the conditions that are present when the DTC sets. This information is stored as Failure Records data only. This information is not stored as Freeze Frame data.

### Conditions for Clearing the DTC

• | The DTC becomes history when the conditions for setting the DTC are no longer present.

• | The history DTC clears after 40 malfunction-free warm-up cycles.

• | The PCM receives the clear code command from the scan tool.

### Reference Information

#### Schematic Reference

• | Instrument Cluster Schematics

• | Engine Controls Schematics for the 2.9L engine

• | Engine Controls Schematics for the 3.7L engine

#### Connector End View Reference

• | Displays and Gages Connector End Views

• | Powertrain Control Module Connector End Views for the 2.9L engine

• | Powertrain Control Module Connector End Views for the 3.7L engine

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Scan Tool Data List

### Circuit/System Testing

1. Ignition OFF, disconnect the EOP switch.
2. Ignition OFF, test for less than 1.0 ohm of resistance between the low reference circuit and ground.

⇒ | If greater than 1.0 ohm, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the PCM.

3. Ignition ON, install a 3-amp fused jumper wire between the signal circuit and the low reference circuit. Verify the scan tool Engine Oil Pressure Switch parameter is Low.

⇒ | If not Low, test the signal circuit of the EOP switch for an open/high resistance. If the circuit tests normal replace the PCM.

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 2.9L engine

• | Engine Oil Pressure Sensor and/or Switch Replacement for the 3.7L engine

• | Control Module References for the PCM replacement, setup, and programming