P0521: Oil pressure sensor/switch range/performance
The oil pressure reading does not fit engine revs or temperature. It may be the sensor, but also the wrong oil or genuinely abnormal pressure.
| Code | P0521 |
|---|---|
| System | Engine and transmission |
| Group | P05xx, Speed, idle and auxiliary inputs |
| Type | Generic: it means the same on every make |
| Can you keep driving? | With care |
What P0521 means
The ECU knows what oil pressure makes sense for a given speed and temperature. If the reading does not fit, for instance it does not rise with revs or shows pressure with the engine off, it sets this code. It may be a sensor misreading or real pressure that is not right.
Most common causes
- Low oil level or oil of the wrong viscosity
- Very old oil or oil diluted with fuel
- Oil pressure sensor reading incorrectly
- Wrong or clogged oil filter
- Problem with the oil pump, relief valve or pickup screen
Symptoms
- Oil pressure light flickering at idle or on bends
- Oil pressure gauge showing odd values, if fitted
- Engine warning light on
Can you drive with P0521?
With care If the level is fine and the engine sounds normal, you can drive carefully to a garage. If the red oil light comes on, stop as soon as it is safe and switch off.
Open the bonnetthe in-depth explanation
How to check it
Check the oil level and condition, and when it was last changed. If your scanner shows oil pressure, see whether it rises with revs and falls at idle; if it never moves, suspect the sensor. A mechanical gauge at the garage will settle it.
How to read and clear P0521 with Final OBD
Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0521 with its description and whether it’s confirmed, pending or permanent.
If the engine stores it over standard OBD, with FREE you read this code with its explanation for nothing and clear it. With PRO you also read the faults of every control unit and clear them in all of them.
Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before an inspection. It’s all in how to read and clear fault codes and in inspections and OBD.
Similar codes
- P051D The sump pressure sensor gives a higher signal than normal
- P051E The sump pressure sensor fails now and then
- P051F The positive sump ventilation filter restriction is not working properly
- P0520 Oil pressure sensor/switch circuit malfunction
- P0522 Oil pressure sensor/switch low voltage
- P0523 Oil pressure sensor/switch high voltage
- P0524 Engine oil pressure too low
- P0525 The cruise control servo control gives readings outside the normal range
- P0500 Vehicle speed sensor malfunction
- P0501 Vehicle speed sensor range/performance
- P0502 Vehicle speed sensor circuit low input
- P0503 Vehicle speed sensor intermittent, erratic or high
To understand it properly
We explain how that system works, with drawings and no waffle, in our mechanics guide: Oil and lubrication.
To understand it properly
We explain how that system works, with drawings and no waffle, in our mechanics guide: Timing belt and chain.
What does code P0521 mean?
The ECU knows what oil pressure makes sense for a given speed and temperature. If the reading does not fit, for instance it does not rise with revs or shows pressure with the engine off, it sets this code. It may be a sensor misreading or real pressure that is not right.
Can you drive with P0521?
If the level is fine and the engine sounds normal, you can drive carefully to a garage. If the red oil light comes on, stop as soon as it is safe and switch off.
How do you clear P0521?
With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P0521 comes back.
Read it on your car
Final OBD reads and clears engine faults through standard OBD for free, each one explained in plain English. With PRO it also reads the faults of every control unit, each make’s own codes included, and clears them in all of them.
