Engine
Variable Valve Timing (VVT)
VVT advances or retards the camshaft to optimize power, torque and fuel economy across the rev range.
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Combustion flow
Interactive — tap a partTap a part to see how it fits in the system.
What it does
- Phases the camshaft relative to the crank
- Adjusts valve timing with oil pressure
- Improves low-end torque and efficiency
When it fails
- P0011–P0021 codes
- Rough idle
- Loss of power
- Ticking from the engine top
How to diagnose
- Check oil level and pressure — VVT runs on oil
- Test the VVT solenoid
- Verify cam/crank correlation
- Inspect the phaser
Maintenance
- Change oil on schedule; dirty oil ruins phasers
- Fix low oil pressure before replacing parts
Use the diagnosis order. When a part fails, confirm each hypothesis with measurements before replacing anything — codes and symptoms overlap.
Related part
Timing Belt / Chain
The timing belt or chain keeps the crankshaft and camshaft synchronized for correct valve timing.