Fix P0021: Mechanic’s solutions that WORKED

The P0021: “Camshaft Position – Timing Over-Advanced or System Performance (Bank 2)” code indicates that the camshaft timing for bank 2 of the engine is more advanced than what the engine control module (ECM) has commanded. This situation can occur due to various reasons, often related to the Variable Valve Timing (VVT) system. The issue can lead to reduced engine performance, increased fuel consumption, and potentially more serious engine problems if not addressed.

P0021 quick overview

Meaning	P0021: “Camshaft Position – Timing Over-Advanced or System Performance (Bank 2)”
Is it serious?	This code is moderately serious and should be addressed soon to avoid potential engine performance issues.
Possible causes	– Variable Valve Timing (VVT) control issue – Oil flow problems to the VVT – Faulty camshaft position actuator – Timing chain or belt problems – Dirty or low engine oil
How to diagnose?	Check Engine Oil: Ensure oil is clean and at the correct level. Inspect Timing Components: Verify timing belt or chain alignment. Test VVT Solenoid: Assess solenoid operation and electrical connections. Evaluate Camshaft Position Actuator: Check actuator for proper functioning.

How to fix P0021 – learn from mechanics

I looked into P0021 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Suzuki

Vehicle Information:
2007 Suzuki XL-7 3.6L

Issue + Repair History:

• Initially came in for timing chain replacement.
• Ran well for 50 miles post-repair, but returned with P0021 code.

Other OBD2 Codes + Test Results:

• P0021: Cam Phaser System Bank 2 Intake

Suggestions to Fix Issue:

• Check engine oil level and quality.
• Inspect the CMP actuator connector and circuit.
• Evaluate engine timing components for damage or wear.

Final Fix:

• An engine flush, along with new oil and filter, resolved the P0021 code related to the left intake actuator solenoid.

Case #2: Nissan

Vehicle Information:
2008 Nissan Frontier Nismo Off-Road 4.0L

Issue + Repair History:

• Vehicle experienced stalling with codes P0011 and P0021 after a new timing chain was installed.
• Replaced phasers and tensioners but issue persisted.

Other OBD2 Codes + Test Results:

• P0011: Cam performance bank A
• P0021: Cam performance bank A

Suggestions to Fix Issue:

• Consider oil change and filter replacement.
• Recheck timing, especially cam phasers and oil control valves.
• Inspect wiring and connectors of related components.

Final Fix:

• The issue was resolved by correctly indexing the flywheel, which was previously misaligned. This corrected the cam timing issues.

Case #3: Infiniti

Vehicle Information:
2005 Infiniti G35 3.5L

Issue + Repair History:

• Car came in with code P0021.
• Oil and filter changed, new solenoid installed, but the code reappeared after a short drive.
• No noise from the chain, engine running fine.

Other OBD2 Codes + Test Results:

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

Suggestions to Fix Issue:

• Check scan data for desired and actual cam degree at idle and 2500 rpm.
• Consider flushing the engine and checking the intake cam sensor’s live data.
• Look into All Data or Identifix for diagnostic information on the code.

Final Fix:

• Cleaning oil sludge from the VVT Actuator and oil passage resolved the issue.

Case #4: Subaru

Vehicle Information:
2005 Subaru Forester XT 2.5L

Issue + Repair History:

• Chronic P0021 code.
• Replaced timing belt, water pump, pulleys, tensioner, turbo, oil control valves.
• New OEM left intake camshaft pulley installed.

Other OBD2 Codes + Test Results:

• P0021: A Camshaft Position – Timing Over Advanced or System Performance Bank 2

Suggestions to Fix Issue:

• Check and change oil.
• Recheck valve timing and alignment.
• Test oil control valve resistance when warm.

Final Fix:

• Replacing a defective oil control valve on bank 2 fixed the issue. New part was defective, replaced again with a functioning one.

Case #5: Buick

Vehicle Information:
2010 Buick LaCrosse CXL 3.0L

Issue + Repair History:

• Customer reported needing timing chains done according to a dealer quote.
• After replacing timing chains, sprockets, guides, tensioners, and cam actuator, codes P0014 and P0021 appeared.
• Vehicle runs well but codes persist.

Other OBD2 Codes + Test Results:

• P0014: Exhaust camshaft position performance B1
• P0021: Exhaust camshaft position performance B2

Suggestions to Fix Issue:

• Ensure the VVT actuators are correctly installed and compatible.
• Double-check the alignment of timing components.
• Consider if an oil change could help.

Final Fix:

• Discovered that VVT actuators come in two different styles (Aisin and Delphi).
• Replaced the thrust washers with a smaller size to match the Delphi actuators used, resolving the issue.

Advice	Diagnostic Step Description
Check Oil Quality and Level	Ensure the engine oil is clean and at the correct level.
Inspect Timing Components	Double-check the alignment and condition of timing chains and sprockets.
Verify VVT Actuator and Solenoid Operation	Test the VVT actuators and solenoids for proper functioning.
Examine Electrical Connections	Check the wiring and connectors related to VVT system.
Confirm Camshaft Alignment	Ensure the camshafts are correctly aligned.