Possible causes

– Low oil level or motor mechanical fault
– Faulty oil pressure sensor
– Oil Pressure Sensor harness is open or shorted
– Oil Pressure Sensor circuit poor electrical connection

When is the code detected?

The P0521 is detected when the signal sent from oil pressure sensor to PCM goes out of range.

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Oil pressure warning light ON.

P0521 SATURN Description

The PCM continuously monitors the engine oil pressure. The Oil Pressure Sensor/Switch sends a signal to the PCM when the engine is running.