P0021Powertrain
Powertrain · SAE
Intake Cam Timing — Over-Advanced (Bank 2)
Meaning
The engine control module has detected that the Bank 2 intake camshaft timing is more advanced than the calculated target and cannot retard to the correct position. The VVT actuator is unable to return the Bank 2 intake camshaft to the intended retarded position.
Common causes
- VVT solenoid (OCV) for Bank 2 intake stuck in open or partially open position
- VVT phaser for Bank 2 intake stuck in the advanced position due to wear or deposits
- Excessive oil pressure or faulty pressure-relief valve holding the phaser in advance
- Degraded engine oil with altered viscosity interfering with phaser drain-back
- Slack timing chain on Bank 2 causing an incorrect position readout
- Incorrect CMP signal on Bank 2 indicating a false advanced position
Symptoms
- Check-engine light (MIL) illuminated
- Rough or unstable idle
- Power loss at low and mid-range RPM
- Possible noise from the Bank 2 timing drive
- Increased fuel consumption and emissions
Severity
High: permanently advanced Bank 2 intake camshaft timing reduces performance and efficiency; can cause phaser and timing-drive damage if not corrected.
What to do
- Verify that the Bank 2 intake VVT solenoid closes correctly with the engine off
- Check OCV solenoid resistance and PWM signal during active diagnosis
- Check engine oil level, quality, and pressure
- Inspect Bank 2 timing chain tension
- Replace the Bank 2 intake VVT phaser if mechanically stuck