Parts
$15–60
P0520 — Engine Oil Pressure Sensor/Switch Circuit
STOPIs it safe to drive? Don't assume your oil pressure is fine just because the code says 'sensor' — treat this like a low oil pressure warning until verified; continued driving risks catastrophic engine damage.
What P0520 means
The ECM is reading an oil pressure signal outside the expected range or behavior. It may be a bad sensor, or it may be real low oil pressure — the code alone can't tell you which. The oil pressure sensor is inexpensive, but the engine is not.
Most likely causes (in order)
- Oil pressure sensor failed (most common after ruling out real low pressure)
- Oil level low — check the dipstick immediately
- Connector corroded on pressure sensor
- Oil too thin, wrong viscosity, or severely degraded
- Oil pump worn or pickup tube clogged (requires oil pan drop to diagnose)
Symptoms you might notice
- oil pressure warning light
- CEL on
- possibly engine knock or ticking if pressure is actually low
- no symptoms if sensor-only
What to check first
Check oil level on the dipstick first. If level is correct, connect a mechanical oil pressure gauge to the sending unit port and run the engine — this tells you actual pressure vs. what the sensor claims. A sensor replacement that masks real low pressure ends engines.
Repair cost & difficulty
Labor
0.5–1 hr
Difficulty
DIY-friendly