P0520Engine Oil Pressure Sensor/Switch A Circuit
- 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. P0520 is the general circuit fault, used differently: Ford petrol and diesel engines set it for the digital SENT sensor when it reports an internal fault, does not initialise or sends values out of range (lost communication is U0600), after 5 s. GM's 1.4 L turbo with an oil pressure switch sets it when the switch reports pressure although the engine has been off long enough to be pressureless – type C, without warning lamp.
- What you may notice
- Check engine light (depending on the maker)
- Oil pressure gauge or warning wrong
- Cam phasing or cylinder deactivation possibly disabled
- Likely causes
- LikelySensor or switch faulty internally
- PossibleConnector corroded or oily (oil creeping through a leaking sensor)
- PossibleSignal line open or shorted to ground
- Rare5 V reference or supply faulty (usually with other sensor codes)
- 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.