What Is The Meaning Of p0521 Chevy Silverado 2011- How To Fix It!

For an engine to operate correctly, it has to have proper engine oil pressure. All the engine’s moving parts are lubricated, reducing friction and damage. Low or high oil pressure signifies something is wrong with the oil pressure sensor.

What does p0521 chevy Silverado 2011 mean?  The p0521 code indicates that the oil pressure switch or engine oil pressure is malfunctioning. The OBD-II code p0521 is generated when the Powertrain Control Module detects irregular engine pressure values.

This article will explain the causes and signs of p0521 and how to fix it.

Overview Of P0521 Chevy Silverado 2011

OBD-II fault code P0521 indicates a defective oil pressure sensor or gauge. The Powertrain Control Module (PCM) manages the vehicle’s sensors, including the oil pressure sensor.

Oil pressure sensors in vehicles are typically three-wire sensors with 5 volts, a signal return ground, and a signal voltage that fluctuates with engine oil pressure.

The sensor’s job is to monitor engine oil pressure and communicate it to the PCM. The oil pressure sensor analyzes the engine’s oil pressure, which is then transmitted as a voltage value to the PCM.

If the voltage analysis is not the same as the average pressure range, i.e., higher or lower, the PCM notices and generates the P0521 code.

p0521 chevy silverado 2011

The Signs of p0521 On Chevy Silverado 2011

Here are some signs of p0521;

  • The check engine light illuminates;  if something goes wrong with any sensor or switch in the chevy, the check engine light will illuminate.
  • Warning light for oil pressure; the oil pressure light on the dashboard panel is linked to the pressure sensor. This warning light activates if the oil sensor detects unusually high or variable pressure.
  • A noisy engine; a defective pressure sensor will transmit a high oil pressure reading to the PCM while the actual oil pressure is low. The PCM will command the oil pump to reduce pressure in this case. Engine noise indicates that your car engine parts are not getting enough lubrication.
  • False oil pressure gauge readings; a pressure gauge collects data from the oil pressure sensor. When you have a defective pressure sensor, it transmits incorrect readings to the meter.
  • Oil light that blinks constantly; implies that the oil pressure has exceeded the standard pressure limits by a significant margin. As a result, the oil pressure warning light begins to flicker.
  • Oil leaks; check near the engine seal and beneath the hood to see if there is any overflowing oil.

P0521 Causes On Chevy Silverado 2011

Here are the causes of p0521 in chevy Silverado 2011.

Low oil levels

As you continue using the car, the oil in the engine reduces. Insufficient oil means the engine parts are not lubricated, which may lead to friction.

Old engine oil

Old or reused oil will not effectively lubricate the engine, and due to its high viscosity, it will lead to friction, making the engine parts wear out.

Incorrect viscosity of oil

Thick oils cause high pressure, which could damage your engine. On the other hand, thin oil results in low pressure, which means it will not lubricate all parts of your engine.

Sludge accumulation inside the engine restricts oil flow

Sludge accumulation can restrict oil passageways in your Chevy engine. This results in high pressure and engine damage.

Dirty filter

Engine filters protect engine components from debris and dirt, which can clog an engine. A clogged filter can cause increased engine pressure.

Therefore, the engine works harder to force the oil through it. Also, a dirty filter can cause a P0102 error code. What does p0102 mean in a Chevy Silverado? It signifies that not enough air is passing through your air filter.

When you press the accelerator, the engine must consume a lot of air. If the air filter is unclean, there will be inadequate air streaming into the intake chamber.

Other Reasons

Below are other reasons I have identified that can cause a p0521 error:

  • PCM fault, i.e., an outdated software
  • A short-ground connection
  • Internal engine wear resulting in low oil pressure
  • Pressure sensor failure
  • Corroded engine parts

How Can I Fix A p0521 Error Code?

If you are unfamiliar with vehicle maintenance, it is better to leave the P0521 code to a professional.

If you are conversant with the truck, the first thing you do is;

  • Check the oil level
  • Next, check the condition of the oil
  • Examine the wiring harness; verify the wiring harness that links the pressure sensor to the PCM to ensure it’s not damaged or corroded. Don’t forget to double-check if the harness is still plugged into the sending unit.
  • If the oil level and wiring are in good condition, the next step is to check the oil pressure manually. You can check the oil pressure with a manual oil pressure gauge kit to determine whether it is correct.
  • If the pressure is correct, it must be a PCM issue. You need an extra oil pressure scan tool to ascertain a PCM issue. That way, you can compare the results from the PCM to those of your scan tool. If the results coincide, then you have to replace your oil pressure sensor, but if not, the PCM is the issue.

The mechanic will narrow down the cause and conduct the following repairs:

  • Replacing old oil with a new one
  • Replaced oil will have a proper viscosity
  • Clean or replace the filters
  • Replace the oil pressure sensor
  • Reset the PCM but if damaged, replace it
  • Replace any frayed or broken wiring
  • Disable v4 mode on the Silverado; v4 mode causes the engine several problems, such as lifter failure, damage to the oil pressure sensor, and high oil consumption. So by disabling it, many engine issues, including the error code p0521, are cleared.


Let’s look at other commonly asked questions.

What is the standard oil pressure in a chevy Silverado 2011?

The average oil pressure is between 25 to 65 PSI. The pressure lowers to about 30 and 20 PSI when the car is not running.

Should I drive with a p0521 code?

No, you should not. If you notice the oil warning light, turn off the engine and call a tow. If you do not immediately address a p0521 error code, you’ll risk paying a lot to fix the damaged engine parts.

How much will I pay for a p0521 fix?

Average labor costs are between $70-$200, depending on the automobile shop. There are additional costs for any parts replaced and also a diagnosing fee. For example, an oil pressure sensor costs $50-$70, and an oil replacement costs $8-$15.

What mistakes happen when diagnosing a p0521?

You might replace good wiring because you did not thoroughly inspect it. In some cases, the mechanic only installs a new oil pressure sensor without checking for other engine damage that might have occurred.


Important things to note about p0521 is that it comes about because of oil pressure sensor issues. The common signs of a p0521 are a check engine light, a noisy engine, and an oil pressure warning light. Do not ignore the signs because it is not safe to drive with a p0521.

The oil pressure issues can cause damage to your engine parts which are very expensive to replace. If you cannot diagnose the p0521 code, take the truck to a professional mechanic.

Hi, this is Johnny Norris grew up in a car-oriented family. I love helping people by solving different problems they face in their Chevy car. Following my suggestions, how-to guides, you can save up on a lot of money that would have been spent on paying a professional.