Bank 1 camshaft timing is more advanced than commanded — a mechanical/hydraulic VarioCam performance fault rather than a pure circuit fault.
SYMPTOMS
- Check-engine light
- Rough idle
- Hesitation
- Power loss
- Increased emissions
LIKELY CAUSES
- Stuck or failed VarioCam adjuster
- Clogged oil control valve
- Low oil pressure
- Worn cam timing components
- Worst case: spun/worn cam timing on a Porsche flat-six
DIAGNOSIS STEPS
- Verify oil level and pressure
- Clean or replace the oil control valve
- Inspect cam position sensor
- Compare actual vs commanded cam angle in live data
- If it persists, inspect timing components mechanically
RELATED PARTS
- VarioCam adjuster
- Oil control valve
- Camshaft position sensor