The secondary air injection system flow is not within the expected range during cold start.
SYMPTOMS
- Check-engine light
- Possible cold-start roughness
LIKELY CAUSES
- Failed secondary air pump
- Stuck combination/change-over valve
- Blocked or leaking air hoses
- Wiring fault
DIAGNOSIS STEPS
- Test secondary air pump operation
- Inspect the combination valve and hoses
- Check pump wiring and relay
RELATED PARTS
- Secondary air pump
- Combination valve