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

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.

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.

In other words, the oil pressure sensor that triggers a P0520 code is typically a three-wire sensor with 5 volts, a signal return ground, and a signal voltage that varies with engine oil pressure. The sensor’s job is to convert engine oil pressure to a voltage reading that the ECM/PCM is programmed to interpret as an accurate indicator of engine oil pressure.

The oil pressure sensor that triggers a P0520 code is typically a three-wire sensor with 5 volts, a signal return ground, and a signal voltage that varies with engine oil pressure.

– Richard McCuistian, ASE Certified Master Automobile Technician

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.

Read our note about oil pressure for different OEMs before you attempt any DIY troubleshooting for code P0520.

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:

• Bad engine oil pressure sensor
• An issue with the oil pressure sensor’s circuit
• An engine problem leading to low oil pressure
• An issue with the PCM, such as software in need of an update

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:

• Noises from the engine
• Vehicle stuck in “limp mode”
• Engine won’t start
• Illuminated oil pressure warning light
• 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.

How to Get a Quality Replacement Oil Pressure Sensor

A bad oil pressure sensor can trigger DTC P0520. The faulty sensor is likely also causing odd engine noises and other engine trouble. If this is the case, replace your oil pressure sensor to get your vehicle back to a safe and drivable state. For quality replacement parts or tools, order here at CarParts.com.

CarParts.com offers a wide range of quality aftermarket parts. We’re happy to sell these parts at different price points to suit various budgets, and our catalog features many trusted aftermarket brands. We’re so confident in our products that we have a 60-day return policy. We believe your peace of mind is important when ordering parts online. So if you aren’t satisfied with the components you’ve ordered, we’re happy to replace them or refund your purchase.

Your vehicle’s bad oil pressure sensor will continue to negatively affect the engine if you don’t replace it. Purchase a new oil pressure sensor today at CarParts.com.

Products Mentioned in this Guide

Oil Pressure Sensor Engine Control Module