Variable valve timing (VarioCam) fault: during a commanded camshaft phase change, the actual position of the "A" camshaft on bank 1 (cylinders 1-3) responds too slowly to match the position the DME requested. Usually oil-flow or actuator related rather than a failed sensor.
SYMPTOMS
- Check-engine light
- Rough or uneven idle
- Reduced power / poor throttle response
- Occasional hard start
- Slight drop in fuel economy
LIKELY CAUSES
- Low oil level, degraded oil, or wrong viscosity
- Clogged camshaft oil control valve (VarioCam solenoid) or its filter screen
- Failing camshaft adjuster / cam phaser
- Stretched timing chain or worn chain tensioner/guides
- Wiring or connector fault at the solenoid
- Camshaft position sensor signal fault
DIAGNOSIS STEPS
- Check oil level and condition; confirm correct grade (Porsche A40 / 0W-40)
- Scan live data: compare commanded vs actual cam timing during a phase change
- Test the camshaft oil control valve solenoid (resistance + actuation) and clean its screen
- Inspect timing chain for stretch and the tensioner/guides for wear
- Check solenoid wiring/connector continuity and the cam sensor signal
- Clear the code and road-test to confirm the fix
RELATED PARTS
- Camshaft adjustment solenoid (oil control valve)
- Camshaft position sensor
- Timing chain / tensioner