P0523Engine Oil Pressure Sensor/Switch A High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- The oil pressure sensor matters for emissions control because modern engines use it as an input – for two-stage or regulated oil pumps, hydraulic cam phasers and GM's cylinder deactivation, whose lifters switch by oil pressure. P0523 means the signal voltage is above its limit: GM 2018 above 95 % of the 5 V reference, GM 2006 above 4.89 V, Ford petrol above 4.75 V, Ford diesel above 4.992 V, about 5 s. Typical are an open sensor ground or a signal shorted to 5 V or battery voltage. Real excess pressure is not reported here – Ford uses P055F for that. GM's 2006 V8s used the warning lamp only with cylinder deactivation.
- What you may notice
- Check engine light (depending on the maker)
- Oil pressure gauge at maximum
- Cam phasing or cylinder deactivation possibly restricted
- Likely causes
- LikelySensor ground open
- PossibleSignal shorted to 5 V reference or battery voltage
- PossibleSensor faulty internally
- RareOil or moisture in the connector
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €50 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.