Oil is the lifeblood of your vehicle. Regular oil changes and proper lubrication can extend the life of your engine. The opposite of that can mean catastrophe for you and your vehicle.

Your oil pressure sensor notifies your ECU when the oil pressure is too low or high. This prevents the worst of scenarios, but it can also happen that your pressure is normal and that the sensor is sending incorrect data. Either way, the P0520 code is the check engine light code that is triggered when things go wrong with your oil pressure.

What is the P0520 Code, and What Does It Mean? 

The P0520 code is an “engine oil pressure” sensor code. It means the voltage the sensor sends to the ECU is out of range. Your engine needs a very specific oil pressure to lubricate mechanical components. A drop or increase in pressure can have catastrophic consequences for your engine.

Where Is the Oil Pressure Sensor Located?

An oil pressure sensor is at the bottom of the engine block. It is the only source of oil pressure information, which means it must sit between the oil filter and the oil pan. This is so the sensor will read accurate pressure numbers straight from the oil pump which is at the bottom of the pan.

What Causes the P0520 Code?

The causes of the P0520 code are all in the oil pressure system. Knowing this narrows down the problem, but even then you’re left with several avenues of approach when it comes to diagnosing this issue. Here are the most common causes of the P0520 code:

• Oil pressure sensor failure
• Incorrect oil
• Failed wiring harness
• Malfunctioning oil pump or relief valve

Oil Pressure Sensor Failure

Your oil pressure sensor is your car’s primary means of measuring oil pressure. A sensor failure usually results in incorrect voltage readings being sent to the ECU, causing a P0520 code. This is a common cause of this trouble code, simply because it’s constantly contacting engine oil. Contaminated oil or soot can damage this sensor. Your oil pump is less likely to be damaged over time from such issues. If you’re looking for quality oil pressure sensors, check out our extensive catalog for Genuine, OEM, and aftermarket solutions.

Incorrect Oil

Modern motor oil lubricates your engine on a cold start and when the engine is running at full tilt. The incorrect oil can cause a drop or increase in oil pressure. This isn’t a common scenario but can cause this trouble code if it occurs. 

Although many car owners opt for a thicker or thinner oil, the sensor is calibrated for a specific type of oil. Luckily, this can be recalibrated fairly easily using an ECU chip or flash.

Failed Wiring Harness

A failure in the wiring harness can cause a host of problems. Excessive resistance, shorts to ground, or voltage loss are all caused by wiring failure. Wiring harness failure is especially common in woodland areas with large rodent populations.

Engine warmth attracts critters who then chew on the wires to sharpen their teeth. Even small wire breaks can cause issues.

Malfunctioning Oil Pump or Relief Valve

Component failure can cause oil pressure to drop and the P0520 trouble code. This is a case where the oil pressure has dropped out of the normal operating range and the sensor is functioning correctly.

What Are the Common Symptoms of P0520 Fault Code?

Although it can be difficult to pinpoint an issue with the oil system, there are tell-tale signs that there is an issue with it. The most common ones are:

• Oil light
• Limp mode
• Clunking or grinding sounds

Oil Light

The oil light is the first indicator of an oil system issue. It will illuminate along with your check engine light when any issues with your oil system occur. This means that it might not be an oil pressure issue even if the light is on. 

The main purpose of this light is to prevent you from continuing further before checking your vehicle. No matter what has caused the oil light to come on, you should immediately pull over and shut the engine off. Continuing driving only increases the risk of catastrophic engine failure. 

Limp Mode

Limp mode is a common feature in modern vehicles. It prevents any damage to internal drivetrain components by locking your vehicle to a low gear or speed. Any damage to the oil system can cause a lack of lubrication and major damage to your engine. As a result, when you have a P0520 code, your vehicle will most likely enter limp mode if it has it.

Clunking or Grinding Sounds

A common sign of a failed oil pump is a ticking or coffee grinder-like noise. This is because the oil pump is attempting to pump but has failed internally. The same noise can occur when your engine is low or is not being lubricated properly due to low oil pressure.

These noises don’t point straight to a P0520 code as many issues make the same noises. Listening for these noises can help you diagnose your issue as it will help you to track down the failed component. 

How to Diagnose and Fix the Cause of P0520 Code 

Every trouble code has specific diagnostic processes. The P0520 is no exception. Here you will find every technique and method for this trouble code and even some quick fixes to get you back on the road.

OBD-II Reader

Your oil system is mostly under the vehicle. Any leaks that can cause a loss of pressure will show up in your driveway. Along with that, inspect your oil pan for damage.

Your oil pressure sensor should be clean and not dented. The wiring harness connected to it should have no fraying. Wiggle the connector because a loose sensor connector can cause the P0520. If it is loose when you put it back in, replace it rather than fix it.

It is possible that you have a seal issue further into the engine, causing oil pressure to drop. First, rule out components that aren’t as deep as the rear main seal, for example. Remove the oil pan and check if the gasket is intact.

Once you’ve removed the oil pan, you can check whether the oil pump is damaged. Note that if you remove the oil pan, you will need a new gasket or oil pan to replace it, regardless of if it has failed or not.

If you plan to test the sensor or wiring harness, it may be better to diagnose those components before removing the oil pan and checking the oil pump.

Wiring Harness Test

Ideally, you want to test for continuity when suspecting a wiring harness issue. However, this doesn’t actually help you track down the cause of the issue in this case. Testing directly at the sensor will tell you whether the connector has failed and that could be causing the P0520 code.

For this test, your vehicle should be in the KOEO (Key-ON engine off) state. Put your multimeter into voltage mode and contact the harness terminals at the oil pressure sensor. Your red probe should touch the signal terminal and your black probe should contact the ground. The ground can be on the wiring harness or the vehicle chassis. Only do this if you know which terminal is which. 

You should get around 0.8V when testing the signal wire and around 10-13V when testing the power wire.

Oil Pressure Sensor Test

Testing for continuity is the best way to diagnose an oil pressure sensor. This is because it normally operates as a closed circuit between its body terminal. You know your sensor has failed when this circuit is open.

Set your multimeter to continuity. The OL symbol should come up on the screen. Contact your red (positive) probe to the body of the sensor and the black (negative probe) to the terminal of the sensor. Either way will work as long as you are touching the metal tab of the sensor terminal. If it stays on OL, your sensor has failed.

The resistance test is the same. Contact your sensor in the same way as above and if there is any resistance, this is your failure point. A closed circuit sensor should read 0 Ohms for an extended period of time.

Still not convinced? Contact the sensor body with a screwdriver while measuring the resistance. If it reads OL, the circuit is open and your sensor has failed.

Does P0520 Clear Itself?

A lack of engine lubrication is a serious issue. Even running your engine for short periods in this state can cause long-term damage. This code will clear itself within a drive cycle, but clearing it with an OBD-II scan tool is safer.

Is It OK to Drive with P0520?

Do not drive with a P0520. Lubrication is one of the leading reasons an engine lasts long or fails prematurely. The causes of this issue are inexpensive and easy to fix. The components that can be damaged if you ignore this issue are not.

Don’t Risk Your Engine, Get Quality Parts

As DIY mechanics, we love fixing our own vehicles. If we could manufacture every part and tool in our garages, life would be perfect. For most people, this is not an option, so you need a supplier that gives you the high-quality parts that you need. 

Diagnosing a P0520 can be tedious, ordering parts doesn’t have to be. Here at eEuroparts.com, we offer an extensive list of parts for all major manufacturers. All you need to do is pick your vehicle and the parts that you need.