P0021 code meaning
"A" Camshaft Position - Timing Over-Advanced or System Performance (Bank 2)
Powertrain system Generic code P00xx codes Check engine light
What P0021 means
The engine control module compares the commanded position of the intake camshaft on bank 2 with the actual position it calculates from the camshaft and crankshaft sensors. This code is set when the camshaft sits further advanced than commanded for longer than a calibrated time, or, depending on the manufacturer, when the target is missed in either direction ("system performance"). Typical cause is a phaser that does not return to its rest position, for example because the oil control valve sticks open or its screen is clogged. Bank 2 exists only on V and boxer engines; it is the cylinder bank without cylinder 1.
P0021 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 8 hours
- Clears after repairAfter a drive cycle
Symptoms of P0021
- Check engine light on
- Rough or unstable idle, as valve overlap is too large
- Engine may stall at idle
- Rattling from the timing drive at cold start
- Higher fuel consumption
Common causes of P0021
- Most likelyOil level too low, oil sludged or wrong viscosity
- Most likelyScreen at the oil control valve clogged with debris
- Most likelyOil control valve mechanically sticking
- PossibleCam phaser worn or its locking pin sticking
- Less likelyTiming chain worn or fitted incorrectly after a repair
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Cam phaser intake bank2Oil control valve intake bank2Engine oilTiming chain
What each part of P0021 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 0 | Area: fuel and air metering and auxiliary emission controls. |
| 21 | The exact fault in that area. |
What to do next
- Note P0021 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0021
What does P0021 mean?
P0021 means ""A" Camshaft Position - Timing Over-Advanced or System Performance (Bank 2)". The engine control module compares the commanded position of the intake camshaft on bank 2 with the actual position it calculates from the camshaft and crankshaft sensors. It is a generic code, so it means the same on every make.
Is it safe to drive with P0021?
Drive gently and only to a workshop. With P0021 the car can go into limp mode (reduced power) to protect itself.
Will P0021 fail an emissions test?
Yes, it can. P0021 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0021 to fix?
Difficulty: medium. A typical repair takes 0.5 to 8 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0021 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.