OBD-II Trouble Codes

P0520 Code: Engine Oil Pressure Sensor/Switch “A” Circuit

Reading Time: 3 minutes

OBD-II codes, otherwise known as diagnostic trouble codes (DTC), are codes stored in cars that have on-board diagnostics. These are standardized codes that are set by the car’s computer if it detects a fault.

There are at least 10,000 different codes under four DTC categories. Knowing what a specific code means will minimize the errors and time spent during troubleshooting. If your scan tool or code reader is showing the P0520 code, this guide will provide its definition, causes, and symptoms.

What Does Code P0520 Mean?

The P0520 engine code is set when the reading from the oil pressure sensor differs from the manufacturer’s specification. Oil pressure is essential to maintain the longevity of every internal combustion engine.

Having the correct oil pressure ensures that there’s a cushion of oil between the rotating internal engine components. The car’s computer or powertrain control module (PCM) monitors the oil pressure by sending a reference voltage to the engine oil pressure sensor. This sensor returns voltage output to the PCM, which is analyzed and compared to the ideal oil pressure programmed in it.

engine control module 4
The PCM monitors the oil pressure by sending a reference voltage to the engine oil pressure sensor.

Inside the oil pressure switch is a pressure-sensing device that’s in direct contact with the oil flow. Oil pressure can either increase or decrease the sensor’s resistance and the PCM is capable of converting these changes into an accurate interpretation of the actual oil pressure.

A working pressure sensor will output a voltage within an upper and lower voltage limit. The lower threshold is purposely greater than 0V so that a circuit check can be performed on the device. If the PCM determines the sensor voltage is outside the ideal threshold for a period of time, the sensor’s signal is deemed invalid and code P0520 is set.

Note: The definition of code P0502 may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Possible Causes of the P0520 Code?

Knowing the possible origin of the problem helps in troubleshooting any trouble code. It is important to know what’s causing the P0520 code before taking action. Make sure to take note of these probable causes:

What are the Common Symptoms of Code P0520?

Be keen in observing any changes in your vehicle. There could be multiple symptoms for code P0520. Here are the common ones you need to watch for:

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One common symptom of error code P0520 is an illuminated check engine light.

How to Diagnose the P0520 Code

There are different ways of diagnosing the OBD code P0520 as it has several possible causes. Don’t expect a universal diagnosis as vehicles are built differently depending on the make and model. It’s a viable option to consult a certified mechanic to avoid inconveniences that may lead to expensive repairs.

How to Fix the P0520 Code

It is possible that the P0520 code in your car requires a different fix than the one you’ve read online. Components in a car may be laid out differently depending on the car manufacturer and this makes it impossible for someone to come up with a universal solution. In addition, there are different designs of oil pressure switches, making a repair or replacement tricky.

To help you with the diagnosis, you can get an ALLDATA single-vehicle subscription, which you can use to help clear code P0520. This subscription will not only help you clear this specific code, it can also help you clear other ones that may be set in the future.

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