P0521 Chevy Silverado: Fixing the Code Error Efficiently

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Knowing the reasons behind the P0521 Chevy Silverado code error is important in order to fix it. The P0521 signal on the dashboard can result from several factors like faulty wiring, low oil pressure, or a blown fuse.

What Is P0521 on the Chevy Silverado

The solutions include checking the oil level and replacing the wire harness.

Why Are You Getting Error P0521 on Your Chevy Silverado?

You are getting Error P0521 on your Chevy Silverado due to any of the following issues: low oil pressure, power steering problems, faulty oxygen sensor, faulty wiring, and faulty power control module. The error could also result from a bad fuse, sludge buildup, and an overheating engine.

– No or Insufficient Oil Pressure

If there is low oil pressure in the system (or no oil pressure at all), you might find your car’s engine light displaying a P0521 error. Low oil pressure can arise from factors like a clogged oil filter, a low oil level, or an oil leak. Dirty or bad engine oil can also be responsible. If you recently changed the oil in your car and got a P0521, chances are you put the wrong oil in your vehicle.

One way you can tell if low oil pressure is responsible for your P0521 problem is to observe your power steering pressure sensor problems. If it’s working fine, then your oil pressure may be the real cause of the issue.

– Power Steering Pressure Sensor Issues

This sensor sends signals to the power steering control module, telling it the amount of pressure in the system. If this sensor is not working properly, it forces the power system into limp mode, triggering P0521. It is always good practice to plug in the sensor properly and ensure it’s getting power. Cleaning the sensor regularly with a suitable solvent is also a good way to prevent future issues.

Solution for P0521 on the Chevy Silverado

Problems with the sensor have proven to be one of the major causes of the P0521. It should be one of the first things you check in your car when troubleshooting for P0521. If you realize that your P0521 problem persists after the basic checks on your power steering pressure sensor, your sensor may have gone bad and needs replacement.

– Bad Power Steering Hoses

If you have worn-out or leaky power steering hoses, you may find your power steering system going into limp mode, resulting in a P0521. To solve this problem, you can start by inspecting the hoses for any leaks or improper connections. If found, rectify such issues as soon as possible.

Another thing you can do is flush the system to remove any debris. However, replacing old hoses with new ones is the best solution for power steering hose problems.

– Power Steering Pump Issues

The power steering pump is the part of a vehicle that supplies hydraulic pressure to the entire system. If there is a leak, low power, or any other problem with this pump, it will trigger P0521. In cases where the pump is damaged, you will have to replace it with a new one.

– Damaged Pre-Catalyst Oxygen Sensor

Your vehicle needs oxygen in its internal combustion engines. The oxygen sensor is located in the exhaust manifold and keeps track of the amount of oxygen leaving the engine. Whenever the oxygen sensor is bad or faulty, the check engine light comes on, and you may get a P0521 error as well.

– Faulty Power Control Module

The Power Control Module (PCM) controls most of the sensors and electronics in a vehicle. If this module is faulty, it will not give accurate readings and may trigger several engine trouble signals. Repairing a PCM is quite difficult and technical, and only a skilled mechanic or the vehicle manufacturers themselves should do it. If you suspect the PCM is the issue, please hand over your vehicle to an expert.

– Faulty Wiring/Connections

Bad wiring or improper connection to the sensor can also cause the P0521 signal to be displayed on your dash. Therefore, your wirings and ground connections must be accurate. If you did any recent customizations or repairs to your vehicle, you should return to check and ensure all the wires are firmly and properly connected.

– Blown Fuse

A blown fuse can cause the P0521 check engine signal to come on. In worst-case scenarios, the car might even refuse to start. To solve this problem, locate your fuse box in your vehicle, pull it out, and inspect it. If it shows any signs of burns, then it’s bad. You should replace it and see if the P0521 signal persists.

But if you can’t find a burnt fuse in your vehicle, then something else must be responsible for the Po521 error.

– The Engine Coolant Temperature Sensor Is Not Working Correctly

An overheating engine will always cause engine trouble signals like the P0521 to pop up on your dash. Likewise, you’ll get the same result if the engine coolant temperature sensor malfunctions. You can always replace this part whenever it fails.

– Sludge Buildup

Sludge buildup in the system will affect the oil pressure sensor and trigger a P0521. The sludge will clog the screens of this oil-sending unit and will cause it to malfunction. Sometimes if the amount of sludge in the engine is too much, it will require manual removal.

Sludge buildup always occurs when you do not change the oil in the engine when due. The oil pressure sensor works best with clean oil, so it’s recommended that you change your oil after every 3,000-mile drive or every three months.

– Short or Open Ground in the Wiring

An improper connection will result in a short in the electrical circuit, ultimately leading to any of the power trouble codes. You should inspect ground connections for any short circuits. Cleaning the wiring connectors can improve contact between the connector and the sensor.

How Can You Fix Error P0521 on the Chevy Silverado?

You can fix error P0521 by checking the oil level, flushing the system, or inspecting the wire harness. The error is an important engine light signal, so you can contact a professional mechanic if you encounter solutions you can’t handle.

– Confirm the Oil Level

This is the first thing to do when trying to rectify the low oil pressure problem. Simply check the oil level by using the dipstick. If you find that you don’t have enough oil in your engine, top it with the right oil.

Change the oil altogether if it looks dirty or messy. Also, if your oil seems to be draining faster than usual, there may be a leak somewhere that you need to plug.

– Inspect Your Oil Filter and Drain Plug

Checking the oil filter and drain plug will reveal the sludge in your car system. If you find any, you need to flush them out immediately. Remember that you should change your oil filter at least once every year.

– Inspect the Oil Pressure Manually

Checking the engine oil pressure manually is not difficult. You only need to get a manual pressure gauging device or testing kit and read the pressure. If the readings differ from those your car displayed, you may have to change your oil-sending unit.

What to Do with Error P0521 On The Chevy Silverado

Remember that you should only go this far if you suspect your oil pressure gauge is bad/malfunctioning. Usually, your vehicle will experience a malfunctioning oil pressure gauge when the oil-sending unit is bad or faulty.

– Check Oil Pressure Sensor Wiring

A wrong oil pressure reading may be because of a wrong connection or a dead or disconnected wire to the oil pressure sensor. You can quickly inspect the wires to see if there are any burnt wires, loose wiring, etc., and verify that everything is as it should be.

– Inspect Oil Pressure Sensor Voltage

Checking this sensor voltage will reveal if your sensor is getting the right amount of power to function properly. You can quickly diagnose the sensor using the DVOM (Direct Volt Ohm Meter).

– Install a New Oil Pressure Sensor

If you do all the checks above and still find no improvement, you can replace the oil pressure sensor with a new one. This course of action is also recommended if you’re using an old oil-sending unit or one you’ve never changed before.

– Check the Wiring Harness

The wiring harness is the collection of wires that connects all the electrical devices in your car to the main power source. Ensure that this harness is firmly connected to the power source and that none of the wires or fuses is bad.



– What Is the Cost of Fixing Error P0521 on Chevy Silverado?

The cost of fixing error P0521 error can be anywhere from $75 to $150. The actual prices will depend on the shop or technician in question. If you have tried different checks and nothing worked, you should see a professional mechanic rather than continue trying to fix it by yourself.

– Can Code P0521 Cause Chevy Silverado Misfires?

Yes, code P0521 can cause Chevy Silverado to misfire, especially when the power steering system is in limp mode. In this case, the power steering system can’t provide enough power to the engine, and this will cause it to misfire.

– What Are the Most Popular Chevy Silverado OBDII Error Codes?

The most popular Chevy Silverado OBDII error codes are P1052, P1306, P1308, and P1309. Other typical error codes that you can encounter while enjoying your chevy silverado are P0560, P0300, and P0422. Apart from this, you can also face a relatively rare error called P0115.

Reasons for P0521 on the Chevy Silverado


Now you know the major causes and solutions to the P0521 code on your Silverado,

let’s go over the major quick fixes you can do:

  • The most popular causes of error P0521 on a Chevy Silverado are low or no oil pressure, faulty wiring, power steering issues, or sludge buildup.
  • Low or no oil pressure can arise from a clogged oil filter, oil leaks, or not enough oil in your engine.
  • To fix error P0521, flush the system, check for leaks, and/or change the oil-sending unit.
  • Also, you should check the wiring and replace faulty or bad fuses, wires, and sensors.

Several factors can cause P0521, and fixing the issue by yourself may take a while. With this guide, you can troubleshoot the possible causes one at a time. But if you want an urgent fix or you need to change something delicate, like the power control module, please take your vehicle to an expert mechanic.


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