"A" Camshaft Position - Timing Over-Advanced or System Performance (Bank 2)
Code P0021 means the PCM has detected that the Bank 2 "A" camshaft (intake cam) is over-advanced or that the VVT system cannot control it within specification. This is the Bank 2 intake cam equivalent of P0011. The intake cam on Bank 2 is stuck in or drifting toward an advanced position. Common causes are low/dirty oil, a stuck-open Bank 2 intake VVT solenoid, or a worn cam phaser.
What You Might Notice
- Check engine light on
- Rough or loping idle
- Hard hot starting
- Stalling at idle
- Poor fuel economy
- Reduced low-RPM power
Most Common Causes
- 1
Low or dirty engine oil
The Bank 2 intake cam phaser cannot retard without adequate clean oil pressure. Low or sludgy oil is the most common correctable cause.
- 2
Stuck-open Bank 2 intake VVT solenoid
A solenoid stuck in the advance position continuously supplies oil to the advance chamber, holding the cam over-advanced.
- 3
Worn Bank 2 intake cam phaser
Internal wear prevents the phaser from holding commanded timing. Ticking noise at idle from the Bank 2 side is a common sign.
- 4
Stretched timing chain (Bank 2)
Chain stretch allows the Bank 2 intake cam to drift toward advance and makes correction difficult.
How to Diagnose It
- 1
Check Low or dirty engine oil — The Bank 2 intake cam phaser cannot retard without adequate clean oil pressure. Low or sludgy oil is the most common correctable cause.
- 2
Check Stuck-open Bank 2 intake VVT solenoid — A solenoid stuck in the advance position continuously supplies oil to the advance chamber, holding the cam over-advanced.
- 3
Check Worn Bank 2 intake cam phaser — Internal wear prevents the phaser from holding commanded timing. Ticking noise at idle from the Bank 2 side is a common sign.
- 4
Check Stretched timing chain (Bank 2) — Chain stretch allows the Bank 2 intake cam to drift toward advance and makes correction difficult.
How to Fix It
- 1
Change engine oil and filter
Fresh oil is the first and most important step for any VVT over-advance code.
- 2
Inspect Bank 2 intake VVT solenoid and screen
Remove and inspect for sludge. Test resistance and replace if faulty.
- 3
Monitor Bank 2 intake cam timing with scanner
Confirm the cam is over-advanced relative to commanded position at multiple operating points.
- 4
Replace Bank 2 intake cam phaser if worn
Replace with OEM-quality parts if phaser is confirmed worn or noisy.
- 5
Check Bank 2 timing chain for stretch
Inspect chain and tensioner if solenoid and phaser are confirmed good.
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