Error P0021 – how to fix?

Code definition P0021

Camshaft Position A – Excessive timing or system performance (Bank 2)

What does the code P0021 mean

P0021 is a generic OBD-II code that indicates that the engine control module (ECM) has determined that the intake camshaft in bank 2 is further extended than the ECM told it to be. This overtime condition may be during camshaft leading or lagging.

What causes the code P0021?

• The camshaft is further forward than the ECM commands.
• The camshaft is further forward when commanded to retract to a lower camshaft position.
• The oil regulating valve (OCV) connected to the camshaft on bank 2 may be stuck or clogged oil lines.
• The oil is too thick, causing clogging of the lines. This could be due to the wrong oil or not having an oil change.
• Camshaft stuck in forward position.

What are the symptoms of the P0021 code?

• The ECM turns on the Check Engine light.
• The engine may idle normally, but may hang or stall when accelerating.
• Due to the non-optimal position of the camshafts, the fuel mileage can be reduced.
• Engine exhaust emissions may exceed federal levels.

Note: Symptoms may vary depending on the timing position when the camshaft has stopped extending or retracting.

How can a mechanic diagnose the code P0021?

• Visually inspect for damaged cables or connectors.
• Check the engine for deposits and that the engine is filled with clean engine oil of the correct viscosity.
• Scanning and documenting codes, then reviewing data from frozen frames to see when a code has been set
• Clear the OBD-II error codes and recheck the vehicle to see if the P0021 code reappears.
• Perform debugging tests for the code P0021 according to manufacturer’s recommendations.

Note: The manufacturer’s fault recovery test will vary for different engines and years of manufacture.

The most common errors when diagnosing the code P0021

Follow these simple tips to avoid misdiagnosis:

1. Perform a visual inspection to detect problems, e.g. check that all electrical connectors are connected or that the harness is damaged.
2. Check that the engine oil is full, clean, and of the correct viscosity.
3. Verify that the error code is active by erasing and retesting the code.
4. Perform step-by-step point tests without skipping any steps.

How serious is the P0021 code?

• The engine can run abnormally and have a variety of driving ailments that can create unsafe driving conditions if the engine wobbles or stalls.
• Fuel consumption may increase and carbon contamination of engine components may occur.

What repairs can remove the code P0021?

1. Clear engine check lamp codes and perform road test to verify code.
2. Change the oil and filter with an oil viscosity according to the engine specifications.
3. Repair or replace the wiring of the camshaft oil control valve for the bank 2 intake camshaft.
4. Replace the camshaft oil regulating valve for the petrol intake camshaft 2
5. Check the timing chain and camshaft chamfers

Additional notes on the consideration of code P0021

Engine oil flows through the camshafts; Oil control valves are small in size and only require the use of oil of the viscosity recommended by the manufacturer. If the oil is smudged or the engine has a higher viscosity of oil, it may cause the VVT ​​camshaft to not function as intended.