| DTC Data Sheet | |
| System | Powertrain |
| Standard | SAE J2012 / ISO 15031-6 |
| Fault type | Performance |
| Official meaning | A Camshaft Position – Timing Over-Advanced or System Performance (Bank 2) |
Bank 2 intake cam timing is over-advanced versus commanded, or the actuator is responding outside the expected window. Mirror to P0011 on bank 2.
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P0021 Quick Answer
Bank 2 intake cam timing is over-advanced versus commanded, or the actuator is responding outside the expected window. Mirror to P0011 on bank 2. The first thing to check is engine oil level, condition, and viscosity — many P002-range faults are oil-driven before they are electrical.
What Does P0021 Mean?
A Camshaft Position – Timing Over-Advanced or System Performance (Bank 2). Bank 2 intake cam timing is over-advanced versus commanded, or the actuator is responding outside the expected window. Mirror to P0011 on bank 2.
Symptoms
- Check engine light
- Rough idle, often unequal between banks
- Loss of low-end torque
- Cold-start phaser rattle on bank 2
Common Causes
- Stuck bank 2 intake VVT phaser
- Blocked oil control solenoid screen
- Stretched timing chain on bank 2
- Sludged oil galleries
- Wrong oil viscosity
- Failed phaser internal components
Diagnosis Steps
You’ll need a scan tool capable of reading live powertrain data, a digital multimeter, and access to the wiring diagram for the specific platform.
- Verify oil level and viscosity.
- Compare bank 2 commanded vs actual cam phase.
- Inspect bank 2 VVT solenoid and screen.
- Check timing chain stretch on bank 2 (separate chain from bank 1 on most V-engines).
Possible Fixes
- VVT solenoid + screen service
- Oil and filter change
- Bank 2 timing chain kit
- Cam phaser replacement
Can I Still Drive With P0021?
The vehicle will usually still drive with P0021 stored, but performance and fuel economy are degraded. The fault disables or limits the affected actuator, and the PCM may inhibit emissions monitors. Drive to a workshop, but don’t ignore the code long-term — VVT and EVAP failures often cascade into related faults if left untreated.
How Serious Is This Code?
P0021 is a moderate-priority fault. It will not prevent the engine from running but will affect drivability, emissions, and over time can damage related components (cam phaser wear, catalytic converter on EVAP-related codes). Address within a few drive cycles.
FAQ
Will P0021 clear itself?
Only if the underlying fault was intermittent and self-corrected. Most P0021 root causes (failed solenoid, wiring damage, blocked screen) are persistent and require physical repair.
Can I clear P0021 without fixing it?
You can clear it with a scan tool, but it will return as soon as the fault condition reappears — typically within one or two drive cycles.
Is P0021 related to other codes?
Often, yes. Cam-position and EVAP faults frequently set adjacent codes — if P0021 is present, scan for related codes in the same range and address them as a group rather than one at a time.