Codes This Page Will Cover
- P0021 “A” Camshaft Position – Timing Over-Advanced or System
- P0022 “A” Camshaft Position – Timing Over-Retarded
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What Is the P0021 Code?
Symptoms
Causes
Seriousness
Can I Still Drive?
Diagnose
Difficulty of Inspecting
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The P0021 code indicates that the Engine Control Module (ECM) senses that the position of the intake camshaft on the bank two side of the engine is more advanced than what the ECM has set it to be. The intake camshaft is part of the variable valve timing system in modern engines and works by increasing engine performance and fuel economy. It does so by controlling when the intake and exhaust valves open and close.
The camshaft’s role in this system is to advance according to the controls laid out by the ECM. The ECM uses data gathered from the crankshaft position sensor and the camshaft position sensor to discern the position and precise location of the shafts. The PCM then dictates to the variable valve timing solenoid to apply a certain amount of oil pressure to an actuator located at the end of the camshaft. Once this occurs, the actuator changes the position of the camshaft and the valve timing exhibited by the engine. When the intake camshaft is more advanced than the ECM dictated, it triggers the P0021 code. If it slows down its position, then the ECM triggers the P0022 code.
What Are the Symptoms of a P0021 Code?
When confronted with the P0021 code, the first symptom is that your ECM triggers the Check Engine Light in your vehicle. You may not notice any immediate physical symptoms, but your engine can normally idle upon start-up and then proceed to hesitate while accelerating. Your engine may also stall out when you come to complete stops because the engine is operating on an insufficient air and fuel mixture. In addition, your engine can start spending more fuel because the camshafts are not in their prime position. This also translates to higher emissions that you will begin noticing with this issue. It may be hard to start your engine in some instances, and you may even experience a rough-riding engine. If the problem is severe enough, then you may hear a rattling or knock from your engine bay. This is a sign that you need to have your vehicle inspected as soon as possible.
What Are Some Causes of a P0021 Code?
There are many potential causes of the P0021 code. The first is that your camshaft may be more advanced than what the ECM has dictated it to be. This also translates in the opposite scenario if your camshaft retarded to a lower timing level. Another potential cause of the issue is if the oil control valve (OCV) is clogged, dirty, or defective and is blocking oil from passing through. If you use the wrong oil or it has the wrong viscosity, then this will also potentially trigger the P0021 code. If your engine oil is consistently dirty or too low, then you risk causing the P0021 issue. There is also the possibility that the camshaft variable valve timing (VVT) control solenoid fails and cannot perform its role. And, finally, if the camshaft phaser seizes up in the advanced position, this will more than likely trigger the code.
How Serious Is the P0021 Code?
The P0021 code can become quite severe if you don’t look after your vehicle once this code sets. As we have shown, your engine may begin experiencing physical driveability issues that could cause hazardous driving conditions. If you are in a vehicle stalling randomly or hesitating in acceleration, then you need to limit your driving. Instead, you should take your car to a qualified service center to have the issue inspected as soon as possible.
Can I Still Drive with a P0021 Code?
If you drive with the P0021 code, then you are emitting more hazardous emissions harmful to the environment and your engine. This is because you can cause excess carbon build-up in your engine, leading to blockages and further damage of engine internals. You are risking higher repair bills and more possibly irreversible damage to your engine by continuing to drive. Technicians recommend that you don’t drive your vehicle if you hear knocking or rattling coming from your engine.
How Easy Is It to Diagnose a P0021 Code?
The first step in the diagnostic process of the P0021 code is to visually inspect all the connected wiring and connectors around either crankshaft or camshaft sensors. A technician will then check the engine for sludge or dirty oil and see if you are using the correct oil in your engine. If you are using an oil with the wrong viscosity, they’ll note that as a potential cause. They will also use an OBD scanner to pull whatever stored codes are there and any available freeze frame data to determine what conditions were in the engine when the ECM set the code. Finally, they will clear the codes and perform a road test with your vehicle to see if the P0021 code reappears. The technician will then check to see if the oil control valve is operating as it should and check the VVT control solenoid for operability.
How Difficult Is It to Inspect a P0021 Code?
The P0021 inspection process requires that you pay meticulous attention to detail and examine many different engine components. A technician is best suited for this type of work and will ensure that your car receives proper care. They don’t recommend that you DIY this process at home because you can easily misdiagnose the issue, repair the wrong part, and cause further damage to your engine’s internals. Instead, a qualified technician will look to change the oil and filter and replace the oil with the correct viscosity that meets your engine’s specifications. They may also repair the wiring around the camshaft oil control valve for the bank two intake camshaft if that’s where the issue lies. If the valve needs replacing, they will replace the entire valve. Finally, they will check that the timing chain is in order and replace the camshaft-phasers.
Need Additional Help with Your P0021 Code?
As we have shown, the P0021 issue is severe and needs proper attention. By following our guidelines, you’ll be able to spot the warning signs of this issue and take the appropriate steps to have your vehicle inspected by professionals. This will ensure that the issue receives the attention it deserves and that your car stays healthy, running longer.
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