P0021 Code: A Camshaft Position Timing Over-Advanced or System Performance (Bank 2)

What the P0021 code means

On an engine with variable valve timing, each camshaft can rotate a few degrees relative to its sprocket to advance or retard valve opening depending on engine speed and load. That rotation is produced by oil pressure, directed by a solenoid that the computer controls.

The P0021 code is set when the real position of the bank 2 intake camshaft does not match the commanded position. P0011 covers the same thing on bank 1.

Because bank 2 is the side of the engine that does not contain cylinder number one, this code can only appear on V-type or flat (boxer) engines. Confirming that physically before you take anything apart saves hours of wasted work, because the two solenoids are identical and sit in mirrored positions.

The order of diagnosis runs from cheap to expensive and almost always starts and ends in the same place. Degraded or sludged oil that keeps the actuator from moving. A clogged solenoid screen. A stuck actuator. And at the end the timing chain, which is where the serious repairs are.

It helps to remember how banks are identified, because it is the most common mistake at the start. Bank 1 is the one that contains cylinder number one, and that cylinder is not necessarily on the side you would expect, since it depends on how the manufacturer numbers the cylinders on that particular engine. The service information states it clearly, and looking it up costs far less than taking apart the wrong side, especially on transverse V engines where one bank sits against the firewall.

A practical note on the order of work on V engines. If the code appears on only one bank, oil and oil pressure are common to both, so they are unlikely to be the cause. The problem is in the solenoid, the actuator or the timing on that side. If codes appear on both banks, that does point to something shared, and oil becomes the first suspect again.

P0021 code symptoms

• Check engine light on.
• Unstable idle, especially with a cold engine.
• Loss of low-rpm torque and a sluggish response.
• Longer cranking than usual.
• Higher fuel use.
• A brief metallic noise at startup.
• Possible correlation codes on the same bank.
• The code appears on one bank only or on both banks at once.

Likely causes of the P0021 code

1. Degraded oil, sludge or oil of the wrong viscosity. The dominant cause.
2. Low oil level.
3. Clogged internal screen in the bank 2 solenoid.
4. Variable valve timing actuator stuck or worn.
5. Oil passages in the control circuit blocked.
6. Solenoid electrically faulty.
7. Stretched timing chain on that bank.
8. Oil pump with insufficient pressure when hot.
9. Camshaft position sensor on that bank with an imprecise signal.

How to diagnose the P0021 code step by step

1. Physically identify bank 2 before you take anything apart.
2. Check oil level, viscosity and condition. Black, thick oil explains most of these codes.
3. Compare with the bank 1 solenoid, which is identical. Its readings give you an immediate reference.
4. Command the solenoid with an active test at idle. The engine should run rough. If nothing changes, oil is not reaching the actuator.
5. Remove the solenoid and clean its internal screen.
6. Measure oil pressure hot and at idle.
7. Compare commanded and actual position in live data.
8. Listen to the engine when cold for timing chain rattle.
9. Check for equivalent codes on bank 1. On one bank only, it points to that solenoid or actuator. On both, it points to oil or pressure, which are shared.

How to fix the P0021 code

• Change the oil and filter with the exact viscosity the manufacturer specifies. In quite a few cases the P0021 code goes away with this alone.
• Clean or replace the bank 2 solenoid and its internal screen.
• Replace the variable valve timing actuator if it is stuck and does not respond to active tests.
• Replace the complete timing kit when the chain is stretched.
• Replace the oil pump if hot pressure is too low.
• Do an internal engine cleaning if there is heavy sludge.
• Prioritize the solenoid and actuator on that bank if the code appears alone, and the oil if codes appear on both banks.

Verify the repair with the engine hot and under load, not only at cold idle.

Technical reference data

• Allowed deviation between commanded and actual position: 5 to 10 degrees.
• Minimum oil pressure for the system to operate: about 1.5 bar (22 psi) at hot idle.
• Typical solenoid resistance: 6 to 12 ohms.
• Bank 2 is the side of the engine that does not contain cylinder number one.
• P0011 is the equivalent code on bank 1.
• The system does not act at cold idle or during the first seconds after startup.
• Code on one bank only: solenoid or actuator on that side. On both: oil or pressure, which are shared.

Brand-specific notes

The big advantage of diagnosing the P0021 code on a V engine is that there is a healthy twin solenoid on the other side. Measure both and compare: resistance, response to the active test and the condition of the internal screen. It is faster and more reliable than hunting for specifications.

If variable valve timing codes show up on both banks at once, stop suspecting the solenoids. The likely cause is oil or oil pressure, which are common to both.

Frequently asked questions about P0021