Bank 1 (cylinders 1-3) secondary-air fault, usually logged alongside the Porsche-specific P1411 (bank 2). The DME sees implausible flow from the secondary-air system during the cold-start catalyst warm-up cycle. On the flat-six the classic cause is brittle cracked SAI hoses; the code is only set during the cold-start SAI window and typically causes no warm-running drivability issues.
SYMPTOMS
- Check-engine light after cold start
- Brief rough/high idle when cold
- Air-pump buzz on cold start
- No warm-running symptoms
LIKELY CAUSES
- Cracked/brittle secondary-air hoses
- Stuck change-over / combi valve
- Failed secondary-air pump
- Vacuum-control leak or bad check valve
- Carbon-clogged air passages
DIAGNOSIS STEPS
- Verify the code sets during the cold-start SAI cycle
- Inspect SAI hoses and the change-over valve
- Confirm the SAI pump runs when cold
- Check control vacuum and check valve
- Clear and re-test cold
RELATED PARTS
- Secondary air injection hoses
- Air change-over / combi valve
- Secondary air injection pump