P0021 Code – Meaning, Causes, Symptoms (& How To Fix)

Learn all about the P0021 OBD-II trouble code. What causes it, symptoms to look out for, and how to fix it yourself.

P0021 Trouble Code

With so many moving parts in the engine, it’s no wonder problems arise over time. When the Check Engine Light comes on and you scan the P0021 code, you need to know what to do next.

In this guide, we review the meaning and causes behind the P0021 trouble code. We also show you the symptoms you might notice and give you some tips to fix them. 

Code P0021 Definition

  • P0021 – Camshaft Position A – Timing Over-Advanced or System Performance (Bank 2)
  • Nissan: Camshaft Variable Timing Control – Bank 2 – Performance

What Does the P0021 Code Mean?

P0021 is considered a generic trouble code that shows when the Engine Control Module (ECM) determines the bank 2 intake camshaft has become more advanced than what the parameters dictate. With this advanced condition, the camshaft timing has moved beyond where it should be.

This explanation applies to most of the main automakers, except Nissan. If you spot the code in a Nissan model, the meaning is Camshaft Variable Timing Control – Bank 2 – Performance instead, although the cause could still be the same. 

P0021 Trouble Code Symptoms

The most prevalent symptom with the P0021 code is that the Check Engine Light will come on. However, it’s also quite likely that there are performance issues occurring as a result of the fault.

Here are a few of the symptoms you might notice.

The symptoms that you are noticing depend mainly on where the camshaft timing position is in relation to where it should be. 

Causes of the P0021 Code

There is more than one cause of the P0021 trouble code, which makes it more important to perform a complete diagnosis before jumping to conclusions. Here are just a few of the possible causes you might discover.

How Serious is the P0021 Code?

Severe – You may not notice any severe issues at first when the code appears. But, if there is something wrong with the timing chain or belt, it can lead to severe engine damage.

If the engine stalls, you could get into an accident. At the very least, you are using up more fuel than needed and you continue contributing to excessive emissions. 

What Repairs Can Fix the P0021 Code?

Based on what you find during your diagnosis, there are multiple fixes that can get you back on the road. Here are a few that you might discover.

  • Perform engine oil and filter change
  • Replace the camshaft oil control valve
  • Repair harness or wiring issues
  • Replace timing valve control solenoid
  • Repair or replace timing chain, belt or tensioner
  • Replace camshaft position sensor

Common P0021 Diagnosis Mistakes

With so many mechanical parts to check, many mechanics will move right past inspecting the oil. Low or contaminated oil could be causing all of the problems.

It would be much cheaper and easier to perform an oil and filter change. That’s why you should always check that first when encountering the P0021 code. 

How to Diagnose the P0021 Trouble Code

Even if you aren’t a professional mechanic, you can troubleshoot the P0021 code the same way that they would. With some simple tools and expertise, it’s easy to figure out what’s wrong if you follow the right steps.

Here are some guidelines to consider.

  1. Read all of the trouble codes. If there are too many at first, you can clear the codes and run the engine until they come back. Freeze frame data is helpful in pinpointing problems.
  2. Inspect the condition of the engine oil. If it’s low, you can fill up the reservoir to appropriate specifications. If the oil is dirty, the only solution is to perform an oil change. Don’t forget to put a new filter in too, ensuring that no sludge is left behind. 
  3. Check the camshaft oil control valve on bank 2 by removing the valve and send power to the solenoid with fused jumper wires. You need to also supply a ground connection. Don’t do this for more than a couple of seconds. If it’s working right, it will click or move. Otherwise, it needs to be replaced. Use a correct repair manual and wiring diagram to not damage anything.
  4. Check camshaft timing, if incorrect a diagnostic procedure must be done to the timing belt or chain.
  5. Inspect the electrical wiring and harness. If there’s any sign of damage, you need to repair it.

Beyond these steps, you could reference your vehicle’s service manual to see if there is any more help based on your model type. Otherwise, it’s best to talk to a professional mechanic for further guidance. 

Estimated P0021 Repair Cost

Once your diagnosis is complete, you know what needs to be repaired. Your next question will be to wonder what the cost is going to be. Here are a few of the common fixes and approximate repair costs if you are paying for the parts and labor. If you do the work yourself, it might be much cheaper.

  • Engine oil and filter change – $45-$150
  • New camshaft oil control valve – $125-$350
  • Repair harness or wiring issues – $50-$550
  • Replace timing valve control solenoid – $150-$450
  • Repair camshaft belt or chain – $1000 – $5000
  • Replace camshaft position sensor – $50 – $200

Mechanics Tips about the P0021 Code

Sadly, there’s always the possibility that the engine oil is full of sludge and there could be permanent issues. Because the oil control valves and camshaft passages are smaller, thick oil can’t get through easily.

If you change the oil but are still noticing trouble with the engine performance, it’s possible permanent damage has occurred. You would want to take your car to a professional mechanic for a closer inspection.