P0520 code meaning
Engine Oil Pressure Sensor/Switch A Circuit
Powertrain system Generic code P05xx codes Check engine light
What P0520 means
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 gasoline 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.
P0520 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P0520
- Check engine light (depending on the maker)
- Oil pressure gauge or warning wrong
- Cam phasing or cylinder deactivation possibly disabled
Common causes of P0520
- Most likelySensor or switch faulty internally
- PossibleConnector corroded or oily (oil creeping through a leaking sensor)
- PossibleSignal line open or shorted to ground
- Less likely5 V reference or supply faulty (usually with other sensor codes)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Oil pressure sensorSensor wiringEngine control module
What each part of P0520 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 5 | Area: vehicle speed, idle control and auxiliary inputs. |
| 20 | The exact fault in that area. |
What to do next
- Note P0520 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0520
What does P0520 mean?
P0520 means "Engine Oil Pressure Sensor/Switch A Circuit". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P0520?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P0520 fail an emissions test?
Yes, it can. P0520 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0520 to fix?
Difficulty: easy. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0520 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.