P0520 Code: Details Explanation

P0520 Definition

The P0520 trouble code relates to a vehicle’s engine oil pressure sensor or switch and its associated electrical circuitry.

What is P0520 code?

P0520 is an OBD-II generic code for an oil pressure sensor threshold problem. The P0520 is triggered when the engine’s computer reads the sensor’s signal from the sensor and it is too high or too low for the manufacturer’s parameters.

If you have red hydraulic oil, you also have a serious mechanical problem.

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What are the causes of the P0520 code?

The most common causes of P0520 are as follows:

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

What are the symptoms of the P0520 code?

Symptoms can range from a check engine light, inoperable oil pressure gauge (if equipped), poor idle, poor engine performance, excessive engine noise, or premature engine failure.

If the error indicates the wrong parameters (high or low values) of any of the sensors or analyzers, most likely this element is normal, and the problem should be sought in the so-called “upstream” in the elements whose work is analyzed by the sensor or probe.

If the error indicates a permanently open or closed valve, you need to approach the solution of the problem wisely and not mindlessly change this element.  There can be several reasons: the valve is clogged, the valve is jammed, and the wrong signal comes to the valve from other malfunctioning nodes.

How does a mechanic diagnose the P0520 code?

When oil pressure becomes a problem, your mechanic will first visually inspect the oil and level in the engine. If it is obvious that the oil has exceeded the change interval, it should be replaced with a new filter.

Next, the pressure sensor should be visually inspected to ensure that it is working properly and that the wiring is not damaged. The sensor can be tested using a digital multi-meter before replacing it.

Common mistakes when diagnosing P0520 codes

Not all P0520s can be attributed to a faulty pressure sensor. This is because poor maintenance of the engine causes the oil pressure to drop. It is important to check for other mechanical failures before replacing any parts. Here are a couple of common examples.

If the error indicates incorrect parameters (high or low values) of any of the sensors or analyzers, most likely this element is normal, as it analyzes (gives out some parameters or values), while the problem should be sought “upstream”, so to speak, in the elements whose work is analyzed by the sensor or probe.

How serious is the P0520 code?

P0520 can be very serious if the oil pressure is actually too low or too high. For example, low oil pressure can cause the crankshaft and connecting rod bearings to grab and the engine to become a tired weight.

What can I do to repair the P0520 code?

The most common repairs for P0520 are as follows:

  • Replace the oil pressure sensor
  • Repair oil pressure sensor wiring
  • Change engine oil and filter

Additional Comments on P0520 Code

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

Engine operation P0520 trouble and other systems of the car (ELM327) do not always point directly to the malfunctioning element. The error itself is an indirect data about the fault in the system, in a sense a clue, and only in rare cases a direct indication of a faulty element, sensor or part.

Errors (error codes) received from the device, scanner requires the correct interpretation of the information, so as not to waste time and money on replacing working elements of the car.

The problem is often much deeper than it seems at first sight. This is caused by the fact that the information messages contain, as mentioned above, indirect information about the malfunction of the system.

Need help with the P0520 code?

Vermin-Club offers certified mobile mechanics who can come to your home or office to diagnose and repair your vehicle. Our resource allows you to ask questions and share your own experiences on troubleshooting the P0520 error. Asking a question within a few days will help you find the answer.

Considering the fact that P0520 trouble in engine or other electronic systems of the car not always point directly to the faulty element and that different makes and models of cars one and the same error can occur as a consequence of failure of absolutely different elements of electronic system we created this algorithm of help and exchange of useful information.

We hope with your help to form the cause-and-effect relation of this or that P0520 trouble in a particular car (make and model). As experience shows if we consider a certain make-model of the car, in the vast majority of cases the cause of the error is the same.


Another point that I would like to note is the specificity of this or that make and model. That is why when you find out about an error in the engine or any other system of your car do not make hasty decisions, but approach the question comprehensively.

This article is written for all users, from simple motorists to professional car electricians. You can have a drop from each and all will be useful in your trouble.

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