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P0520 OBD-II Trouble Code: Engine Oil Pressure Sensor/Switch Circuit Malfunction

diagnostic check engine light

P0520 definition

A P0520 trouble code is related to a vehicle’s engine oil pressure sensor or switch and its associated electrical circuit.

What the P0520 code means

P0520 is a OBD-II generic code for threshold issue with the oil pressure sensor. If the engine computer reads a signal from the sensor that is either too high or too low in relation to the manufacturer’s parameters, a P0520 will be triggered. If a red oil pressure light is associated, there could be a serious mechanical problem as well.

What causes the P0520 code?

The most common causes for a P0520 are:

  • Faulty oil pressure sensor/switch
  • Faulty oil pressure sensor/switch wiring
  • Faulty oil pressure from dirty engine oil
  • Faulty oil pressure from a lack of compression

What are the symptoms of the P0520 code?

Symptoms will vary from nothing more than a check engine light and inoperable oil pressure gauge (if equipped), to rough idling, poor engine performance, excessive engine noise, and even premature engine failure.

How does a mechanic diagnose the P0520 code?

With any oil pressure issue, your mechanic will first visually inspect the engine’s oil and levels. If it’s obvious the oil has surpassed its change interval, it should be changed with a new filter. A visual inspection of the pressure sensor will come next to ensure it is properly seated and the wiring is not damaged. The sensor can be tested using a digital multi-meter before being replaced.

Common mistakes when diagnosing the P0520 code

Not all P0520s are caused by faulty pressure sensors as poor engine maintenance can result in poor oil pressure. It’s important to check for other mechanical failures before replacing parts.

How serious is the P0520 code?

A P0520 can be very serious if the oil pressure is indeed too low or too high. Low oil pressure for example can cause the crankshaft and connecting rod bearings to seize, reducing an engine to a glorified paper weight.

What repairs can fix the P0520 code?

The most common repairs for a P0520 are as follows:

Additional comments for consideration regarding the P0520 code

If you encounter a P0525 with a red, oil light, it’s imperative that you stop the vehicle as quickly and as safely as possible before any catastrophic engine damage results.

Need help with a P0520 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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