P0520: Engine Oil Pressure Sensor/Switch Circuit

What does P0520 mean?

The engine oil-pressure sensor or switch circuit has an electrical fault. A bad sender can create a false warning, but actual low oil pressure must be ruled out before assuming the engine is safe.

Generic OBD-II definition: Engine Oil Pressure Sensor/Switch Circuit. Confirm applicability in your vehicle service information.

Common causes

• Faulty oil-pressure sender
• Damaged wiring or poor connector
• High resistance or a short in the sender circuit

Symptoms

• Oil-pressure lamp or abnormal gauge
• Check engine light
• May run normally despite an unreliable reading

Diagnostic focus

An electrical code does not cancel an oil-pressure warning. A normal dipstick level also does not prove that the oil pump is creating adequate pressure.

Can I keep driving with P0520?

Severity: High Treat a red oil-pressure warning, near-zero gauge reading, or engine knocking as an emergency: stop safely and switch off the engine. Do not keep restarting it. Have actual oil pressure checked before driving.

If the check engine light is flashing or the car runs badly, stop driving and have it checked.

Typical fixes

• Stop for a red oil warning and check oil level safely
• Inspect sender wiring for leaks and damage
• Have actual pressure verified with a mechanical gauge before concluding it is electrical

Sources & review

• OBD-Codes.com: P0520
• TroubleCodes.net: generic code definitions

Definitions and diagnostic background checked 2026-11-06. Generic guidance, not a substitute for the service procedure for your exact year, engine, and transmission.