What is P0521 Code on Chevy Silverado, and How to Fix it?

Once there is an excess or less oil pressure in your Chevy Silverado’s engine, the P0521 signal pops up. Your car sensor measures the oil pressure in the engine, which is then sent to the ECM in the voltage value. Your Chevy Colorado needs the right amount of oil pressure circulating in the engine to keep it running.

Let’s take you through easy steps on how you can fix this problem.

What is P0521 Code?

The P0521 is an engine error code that means ‘Engine Oil Pressure Sensor/Switch Performance’. This code is the generic OBD-11 power code which gets triggered whenever there is a fault within the pressure gauge of the engine oil.

Although the P0521 can affect any OBDII-equipped engine which was built anytime after 1966, the cause and method of repairing the P0521 code differ from car model to model. The mechanic would also need to check the manual of the vehicle for some assistance.

What are the Causes of P0521?

There are a few causes of this error. So whenever you see it, you know these are the problems and the next steps to take to solve them.

Low Oil or None

If your Chevy Silverado shows the P0521 code, then it means that your engine lacks enough oil in it or there is none at all. The code pops up so you can take action by filling the oil in your car’s engine.

Oil Pressure

We have already mentioned that once the oil pressure seems too much or low, the oil pressure gauge on your dashboard will likely show up.

Bad Oil

Most times, people put the wrong oil into their vehicle’s engine. Bad oil is not good for your car’s engine, and it may even lead to it knocking, so to tell you the oil you put is bad or dirty, the P0521 error shows.

Wrong Wiring

There might not be a problem with the oil or the oil pressure, but perhaps wrong wiring occurred during a repair. You should take it to a repairman or if you know how you should check it yourself.


In most cases, the sensor may have a fault, and it is right that you fix the problem. But the first thing you should do is to check the oil or the oil pressure.

Symptoms of the Error

Some signs come with the P0521 code.

Check Light

The check engine gauge or light shows on your dashboard whenever you kick your car’s engine. The check light is the first thing that shows up when this P0521 code comes on.

Engine Stalling and Knocking

In times like this, it will take time for your car’s engine to kick. You may have difficulty starting your car’s engine, or your engine knocks. The use of bad engine oil usually causes engine knock.

Oil Pressure Gauge

The oil pressure gauge will also come up on your dashboard. This usually happens if the oil pressure sensor is faulty or there is low oil pressure.

Engine Noise

When you kick your car or drive, your Chevy engine makes a loud noise.

How to Get Rid of the P0521 Code on Chevy Silverado

If you want to get rid of the P0521 code on your Chevy Silverado, the first step you need to take is to run a diagnosis. It is important to run a diagnosis because you cannot start fixing a problem if you do not know its cause. So once you do, you can go ahead.

To do that, run through the following steps.

Step 1: Examine The Oil’s Level

If you’re going to do it yourself, the first step is checking the engine’s oil level. When you pull out the engine oil dipstick and notice the oil is low, you will need to pure in a new one. If the oil on the dipstick is black and thick, it suggests a change. Such oil (dark and thick) may cause an interruption in the oil pressure.

Step 2: Examine The Engine’s Oil Filter and its Drain Plug

In some cases, the oil filter and the drain plug may have leakages. This can cause the oil in the engine to finish up fast. If there is a leakage, you will need to patch it up and then fill up your engine with oil again.

Step 3: Examine The Engine for wiring connections

The next thing you will need to do is to check the oil pressure wiring. You must ensure that the oil pressure wire is properly connected to your car’s PCM. A bad connection may cause the oil pressure gauge to come on even when the oil you put in the engine is good and is still at the right level.

Step 4: Examine the Vehicle’s Oil Pressure Manually

After you have followed the steps above and the P0521 code has not disappeared, you will need to follow step 4. It is very easy to do so by using a manual gauge to check oil pressure.

Step 5: Buy A New Oil Pressure Sensor

After you have checked the oil pressure using the manual gauge, and it measures just fine, you will need to buy a new sensor. It means that the one currently in your Chevy Silverado is faulty. They are not pricey if you want to change them.

Ensure that you have checked the oil in your car’s engine and the wiring system of the oil pressure before you buy a new oil pressure sensor. Most people make this mistake. Make sure you do not do the same.


Now you know what the P0521 code is and how you can get rid of it. Once you know the parts of the engine for your vehicle, it makes the work a lot easier. You will find it easier to locate the oil dipstick, oil cap, wiring system, and many other things.

If you cannot fix the problem above, although this article provides you with accurate information on the cause, how to know the problem, and how to fix it, you can go ahead and take your vehicle to a mechanic.

Liam Dare

As CEO of ReplicarClub.com, my passion for the automotive world motivates me to build online businesses that provide information and entertainment to users. I am proud to contribute in a positive way to the automotive community.