P0523: Engine Oil Pressure Sensor/Switch A High
What to do
Usually driveable, and more likely to be wiring than a mechanical problem. Still worth checking the oil level and confirming the correct grade was used at the last service.
What this code means
The oil pressure signal is above its plausible range. This is the more reassuring of the two voltage faults, because on most sensor designs an implausibly high reading corresponds to an open circuit rather than to a dangerous pressure — a sensor that has failed open, a broken wire, or a disconnected connector.
A genuinely excessive oil pressure is possible but rare, and generally means a stuck pressure relief valve or oil far too thick for the temperature. It is worth excluding on an engine that has just had an oil change with an unusually heavy grade.
Likely causes
Start here
- Open circuit in sensor wiring · moderate
- Faulty oil pressure sensor · moderate
- Corroded or loose connector · easy
Less common
- Signal wire shorted to voltage · moderate
- Incorrect oil grade or degraded oil · easy
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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