Parts
$15–60
P0523 — Engine Oil Pressure Sensor Circuit High
CAUTIONIs it safe to drive? The sensor is reading higher than possible — probably a bad sensor or wiring, not a real pressure problem; still worth verifying before driving long distances.
What P0523 means
The oil pressure sensor signal is stuck at or above 4.8V, which represents a pressure beyond the physical limit of the system. This high-side fault is almost always a sensor or wiring issue rather than real overpressure, but confirm it before dismissing it.
Most likely causes (in order)
- Oil pressure sensor failed with open circuit or internal fault pulling signal high
- Wiring open between sensor and ECM (open circuit defaults signal high)
- Connector pin backed out on signal wire
- Wrong sensor installed (wrong pressure range or thread size)
- Reference voltage wire crossed with signal wire
Symptoms you might notice
- CEL on
- oil pressure gauge pinned to maximum
- no driveability impact in most cases
What to check first
Unplug the sensor connector and check signal wire voltage with the key on — should drop to near 0V when sensor is disconnected if ECM is pulling it low. If it reads 5V with sensor unplugged, the signal wire is shorted to the 5V reference or there's an ECM issue.
Repair cost & difficulty
Labor
0.3–1 hr
Difficulty
DIY-friendly