P0021: The intake cam on the right side is too far advanced
"A" Camshaft Position - Timing Over-Advanced or System Performance (Bank 2)
Bank 2 intake cam timing is more advanced than the computer asked for. Get it checked within a few days and avoid high revs. If it runs rough or loses power, stop driving.
Stop driving and get help if
- The check engine light is flashing
- The temperature gauge runs high, or you see steam (overheating)
- The car loses power, hesitates badly or stalls
- You smell burning or see smoke
- A brake warning light comes on, or the brakes feel different
Pull over as soon as you can, turn the engine off, and call a tow or roadside help.
What it means
The intake cam on bank 2 has moved further toward advance than the computer commanded, or it cannot return from advance. This is the bank 2 equivalent of P0011. The solenoid that controls this cam is most likely stuck open in the advance direction, often from sludge buildup. If you also have P0020 on bank 2, start with the wiring or oil. If P0021 is alone, the solenoid or phaser on bank 2 is the target.
Common causes
- Stuck VVT solenoid in the advance position on bank 2Sludge holds the solenoid open so the cam advances and cannot return to neutral.
- Dirty or old engine oilOld oil thickens and clogs the fine passages inside VVT solenoids on both banks.
- Worn bank 2 intake cam phaserA phaser that has lost internal sealing pressure drifts to advance under oil pressure.
- Timing chain stretch on bank 2On engines with separate chains per bank, one chain can stretch before the other.
What the fix could involve
From the cheaper fix to the bigger one. Prices depend on your car, your area and the shop, so ask for a written quote that names the part and the labor before you approve it.
- VVT solenoid (bank 2)
- Cam phaser (bank 2)
- Timing chain kit
Symptoms
- Check engine light on
- Rough idle
- Stalling at idle, especially when warm
- Reduced acceleration
- Lower fuel economy
What to do next
Change the oil if it is overdue, reset the code, and test drive. If P0021 returns, replace the bank 2 intake VVT solenoid. The solenoid is the most cost-effective first step. If the code persists after a new solenoid, the phaser is likely worn and needs replacement. Check for any cold-start chain rattle before committing to a phaser job.
Lewis reads P0021 alongside any related cam timing codes on both banks, so you can see whether the problem is isolated to Bank 2. Get Lewis on the App Store or Google Play.
Related codes
FAQ
- Why does my car stall at idle with P0021?
- An over-advanced intake cam on bank 2 changes the air-fuel mixture at low RPM. The engine can stall when the cam is stuck far into advance at idle speeds.
- Can I fix P0021 myself?
- The VVT solenoid swap is a reasonable DIY job on many V6 and V8 engines. The phaser or timing chain requires more skill and usually goes to a shop.
- Does P0021 affect both banks?
- No. P0021 is specific to bank 2. It only affects the cylinders on that side. Bank 1 equivalents are P0011 and P0012.
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