P0521 code — how to fix error fast

Problem codes that affect your car’s engine are the worst kind, and diagnosing a code like the P0521 can be quite intimidating for drivers. If this happens to you, the first thing you’ll probably want to look into is the P0521 code meaning and how it can reflect on your car’s engine performance.

Since it’s a pretty serious situation, we wanted to give you a hand by guiding you through all the symptoms and causes behind the issue, as well as keep you posted on a few ways to diagnose the issue. To make the matter more challenging, there are several main culprits behind the code, so we’ll also discuss how you can prevent it from happening again in the future.

Why you can trust REREV’s OBD2 code advice: Our automotive expert researchers with experienced mechanics undertakes a thorough research methodology to deliver precise insights on OBD codes. Find out more about OBD2 codes research process..

What does the P0521 code mean?

The P0521 code is related to the engine oil pressure sensor circuit. This code indicates that the engine oil pressure is too low or too high, which can cause damage to the engine. It usually manifests through a flashing oil pressure light on your dashboard and could lead to expensive repairs if left unattended.

Some of the main symptoms of the code include frequent engine overheating and odd noises like ticking and rattling coming from the engine bay. As you are probably aware, engine oil lubricates the inner engine components and ensures smooth operation, so you can guess how bad it is for the engine to be deprived of proper oil pressure.

What causes the P0521 code?

Among the symptoms of the code P0521, there’s also the infamous “rod knock” that occurs once the bearings get oil deprived and it could lead to the engine’s pistons striking right into the cylinder head and internally damaging the engine.

So, it’s important to get to the possible causes of the issue and the code P0521 so you can take proper action to fix it. In that light, here are some of the most frequent reasons behind the code:

Faulty oil pressure sensor

A faulty oil pressure sensor can trigger the code P0521 if the sensor circuit sends out a signal that is outside of the expected range. If there’s a sensor malfunction, an incorrect set of metrics will get sent to the engine control unit (ECU) and it can also affect the operation of the oil pump besides triggering the code.

Lack of engine oil

Sometimes the issue can be as simple as a lack of oil within the system, so there’s no proper pressure buildup if the oil level is below expected. However, in this case, the code can serve as an alert to check the oil hoses and see if there’s a leak somewhere within the system.

If not, topping up your oil should do the trick and resolve the issues with the code P0521.

Malfunctioning oil pump

A malfunctioning oil pump can also lead to code P0521. The oil pump is responsible for circulating oil throughout the engine and maintaining appropriate oil pressure, which is crucial for proper engine function. If the oil pump fails or malfunctions, it can cause a drop in oil pressure that triggers the P0521 code.

Damaged wiring harness

The wiring harness is responsible for transmitting signals between the engine oil pressure sensor and the engine control unit (ECU). If the wiring harness becomes damaged or has a short circuit, it can disrupt the signal to the ECU and trigger the P0521 code.

Which car models does the P0521 code affect the most?

It’s difficult to say that a certain car model will have issues with the code P0521 while others won’t since it can happen to any car model out there. Still, some vehicles have truly faced these problems more often than others, at least as stated by the owners.

Overall, older vehicles with high mileage are more likely to experience problems with the P0521 code. This is because the wear and tear on engine components over time can increase the likelihood of oil pressure sensor or oil pump failures. Additionally, vehicles that are driven under harsh conditions, such as extreme temperatures or heavy loads, may also be more prone to these issues.

Here’s our list of the most commonly reported vehicles to struggle with the code P0521:

• Chevy Silverado: The Chevy Silverado can suffer from the P0521 code due to a faulty oil pressure sensor or a bad oil pump.
• GMC Sierra: A damaged wiring harness can also lead to the P0521 code in the GMC Sierra.
• Dodge RAM: The engine oil pressure sensor circuit can cause a malfunctioning sensor or problems with the oil pressure system in Dodge Ram.
• Ford F-150: The F-150 is known to have issues with the oil pump issues that could lead to the code P0521.

As you can see, these often include pickup trucks that feature high-displacement engines and are often used for towing and carrying heavy loads, but it’s not an exact science.

How to diagnose the P0521 code?

Even if you just get the flashing warning light on your dash that may appear and disappear, it’s enough of a concern cause to have things checked. Using a scanner tool will often lead to the code P0521 being uncovered as the source of the issue, but it’s essential that you know all the possible diagnostic methods.

Here’s our list of the ways you can diagnose the code P0521 yourself without a help of a mechanic:

Use a diagnostic scanner on the vehicle’s OBD2 port

The easiest way of diagnosing code P0521 is to use an OBD2 scanner tool and get all the other codes associated with this one to closely describe the issue and help you find a solution.

Check the oil pressure sensor

You can use a multimeter tool to test the capacity of the oil pressure sensor. If it’s out of sync, it means that the ECU can’t receive proper information about the oil pressure buildup within the oil hoses that go through the engine block in your car, therefore leading to the code P0521 to trigger.

Check the engine oil level and oil system in your car

While you can check the engine oil level in your car yourself using a dipstick, it takes a few more steps to finally understand if everything is all right with the oil system. This includes a professional mechanic taking a look at the system, and you can also check for oil dilution to see if the condition of engine oil is according to the manufacturer’s specifications.

Using a high-end diagnostic toolkit can also help you read other codes that may be associated with the P0521 code, and these related codes can also help figure out the exact source of the trouble.

How to fix the P0521 code?

To fix the P0521 code, there are several methods that drivers can use. These methods may vary depending on the underlying cause of the issue. Here are some possible approaches:

Use an OBD2 scanner tool

The first step in fixing the P0521 code is to connect a diagnostic scanner to the vehicle’s OBD-II port and read the code. This can help identify the underlying cause of the issue and provide guidance for further troubleshooting.

Check the wiring harness components and the sensor

Once the code has been read, it is important to inspect the oil pressure sensor and wiring harness for any damage or wear. If these components are damaged, they will need to be repaired or replaced in order to fix the issue.

Use a multimeter on an oil pressure sensor

To test the oil pressure sensor, you can use a multimeter or pressure gauge to check its electrical resistance and compare it with the manufacturer’s specifications. If the readings are outside of the expected range, you may need to replace the sensor.

Check the oil level and top up if necessary

It is also important to check the oil level and condition to ensure that there are no leaks or damage to the engine oil system. Low oil pressure can trigger the P0521 code, so it is important to maintain proper oil levels and keep your engine’s oil system in good condition.

How to prevent the P0521 code?

To prevent the P0521 code from appearing, it’s important to properly maintain your vehicle by using the following servicing actions:

• Regular oil changes
• Checking the oil level
• Inspecting the engine oil hoses for leaks or damage
• Checking the oil pressure sensor and wiring harness

Some engines are simply known for wasting more engine oil than others, so it’s only natural to check your oil level frequently and top up if necessary. You should also keep an eye out on the engine’s temperature in your car, and taking all these maintenance-related steps is the only way to prevent having to deal with the P0521 code.

Our take

Eventually, it all comes down to keeping track of your car’s engine oil level and doing regular maintenance to avoid getting the code P0521 displayed. However, if you do read the code, it’s essential to act immediately and fix the root cause before things get more serious for your car’s engine.

In that sense, we hope to have helped at least a tiny bit through this guide so you can now get a proper understanding of the code and its meaning, as well as ways of diagnosing and fixing it.