P0521

P0521-ENGINE OIL PRESSURE SENSOR PERFORMANCE





For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The Engine Oil Pressure Switch is used by the Powertrain Control Module (PCM) to monitor the lubricating oil pressure. The Oil Pressure Switch is normally closed when the engine is not running or oil pressure drops below the engine protection limit, and open when oil pressure is present. This monitor checks for the Oil Pressure Switch state to change from open to closed in a calibrated period of time after the engine is turned off. When the fault is set, the PCM illuminates the oil pressure lamp on the Vehicle Information Center. The PCM will turn off the oil pressure lamp after the diagnostic runs and passes on the next key cycle.

- When Monitored:
This monitor runs for a calibrated amount of time after the engine speed reaches zero.

- Set Condition:
The Oil Pressure Switch is in a closed state after a calibrated amount of time with the engine speed equal zero.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. CHECK THE ENGINE OIL PRESSURE (EOP) SWITCH
1. Turn the ignition off.
2. Disconnect the Engine Oil Pressure (EOP) Switch harness connector.

NOTE: Check connectors - Clean/repair as necessary.

3. Measure the resistance between the EOP (G6) Signal circuit terminal and ground at the Engine Oil Pressure Switch.

Is the resistance below 5.0 Ohms?

Yes

- Go To 2

No

- Replace the Engine Oil Pressure Switch.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

2. CHECK THE EOP (G6) SIGNAL CIRCUIT OPEN/HIGH RESISTANCE
1. Disconnect the C1 PCM harness connector.

NOTE: Check connectors - Clean/repair as necessary.

2. Measure the resistance of the (G6) EOP Signal Circuit between the Engine Oil Pressure Switch harness connector and the PCM C1 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 3

No

- Repair the (G6) EOP Signal Circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

3. POWERTRAIN CONTROL MODULE




1. Reconnect the C1 PCM harness connector.
2. Engine Oil Pressure Switch still disconnected.
3. Turn the ignition on.
4. Measure the voltage between ground and the (G6) EOP Signal circuit at the Engine Oil Pressure Switch harness connector.

Is the voltage between 4.5 and 5.5 Volts?

Yes

- Perform the INTERMITTENT CONDITION - 6.7L diagnostic procedure. Intermittent Condition Test

No

- Replace the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.