P0520
Engine Oil Pressure Sensor/Switch A Circuit
Engine oil pressure
Generic OBD-II
High
What it means
P0520 indicates a fault in the engine oil pressure sensor/switch "A" circuit. It's an electrical/sensor code — most often a failed sensor, wiring, or connector — but because it also disables a reliable oil-pressure warning, the safe first step is to verify actual oil pressure with a mechanical gauge before ruling out a real low-pressure condition.
High
Can I keep driving? Drivable, but with caution — the code is in the sensor circuit, so your oil-pressure warning may be unreliable; confirm actual oil pressure is good before continuing.
Common symptoms
What you'll notice
- Check-engine light on
- Oil pressure gauge reads erratically, zero, or pegged high
- Oil pressure warning light on or flickering
- No oil-pressure reading on the dash
Common causes
Most likely first
- Faulty oil pressure sensor/switchLikely
- Open or short in the sensor circuit wiringCommon
- Corroded or loose sensor connectorCommon
- Genuinely low oil pressure or an oil leak (must be ruled out)Less often
- Failed instrument cluster or ECM (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data, then confirm real oil pressure with a mechanical gauge before assuming it's only a sensor — this rules out a dangerous low-pressure condition.
- Inspect the sensor connector and wiring for damage, corrosion, or a short/open.
- Replace the oil pressure sensor/switch if actual pressure is good but the signal is faulty.
- Address any real low-pressure or leak issue found, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0520?+
Only after you've confirmed oil pressure is actually normal. The code is a sensor-circuit fault, but because it can mask a real low-pressure problem, verify pressure with a mechanical gauge first.
Can I just clear P0520?+
Not until the circuit is diagnosed. If it's a wiring or sensor fault the code returns, and clearing it could hide a genuine oil-pressure issue.
Related codes
Often seen with P0520
Read & clear P0520 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX