Error P0021 – how to fix it?

Definition of the P0021 code

Camshaft position A – Excessively advanced system time or performance (Bank 2)

What does the P0021 code 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 more advanced than the ECM told it to be. This override condition can be during early or delayed camshaft timing.

What causes code P0021?

• The camshaft is more advanced than the one commanded by the ECM.
• The camshaft is more advanced if it has been commanded to reverse to a lower timing level.
• The oil control valve (OCV) connected to the camshaft on bank 2 may be blocked or have clogged the oil lines.
• The oil is too thick, causing the lines to clog. This may be due to improper oil or lack of oil change.
• The camshaft is stuck in the forward position.

What are the symptoms of the P0021 code?

• The ECM will turn on the Check Engine light.
• The engine may run normally at idle, but may shut down or limp when accelerating.
• Fuel mileage may be reduced due to suboptimal camshaft positions.
• Engine emissions may exceed federal levels.

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

How can a mechanic diagnose the P0021 code?

• Visual check for damaged wires or connectors.
• Check that there are no deposits on the engine and that the engine is filled with clean engine oil of the correct viscosity.
• Scan and document codes, then review frozen frame data to see when the code was set
• Clear OBD-II error codes and recheck the vehicle to see if the P0021 code reappears.
• Perform troubleshooting tests for the P0021 code according to the manufacturer’s recommendations.

Note: The manufacturer’s troubleshooting test will vary for different engines and production years.

The most common errors when diagnosing the P0021 code.

Follow these simple tips to avoid misdiagnosis:

1. Perform a visual inspection for problems, such as checking that all electrical connectors are plugged in or the harness is damaged.
2. Check that the engine oil is full, clean, and of the correct viscosity.
3. Check if the error code is active by clearing and retesting the code.
4. Perform point tests step by step without skipping any steps.

How serious is the P0021 code?

• The engine may run abnormally and have various discomforts while driving, which can cause unsafe driving conditions if the engine hesitates or stalls.
• Fuel consumption may increase and engine components may become contaminated with carbon.

What repairs can clear the P0021 code?

1. Clear the check engine light codes and perform a road test to verify the code.
2. Replace the oil and filter with an oil of the correct viscosity for the engine specifications.
3. Repair or replace the wiring for the oil control valve on the bank 2 intake camshaft.
4. Replace camshaft oil control valve for gasoline bank intake 2.
5. Check timing chain and camshaft phasing units

Additional comments on the inclusion of code P0021

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