OBD-II code · Powertrain (generic, extended)
P25F6 AIR System B
A general fault in the second secondary air injection (AIR) circuit. Detected by the O2 sensors which expect a lean swing during cold-start AIR pump operation but do not see one.
Is it safe to drive with P25F6?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelyFailed AIR pump motor or impeller
- PossibleCheck valve seized by exhaust soot
- PossibleCorroded or cracked air injection pipe
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1.5–5 h
- Emissions test
- Likely to fail
- Parts involved
- Air Pump B, Air Check Valve, Air Pipes
Related codes
- P25F3Turbocharger/Supercharger Boost Sensor C Circuit Range/Performance
- P25F4Turbocharger/Supercharger Boost Sensor C Circuit Low
- P25F5Turbocharger/Supercharger Boost Sensor C Circuit High
- P25F7AIR System B Incorrect Flow Detected
- P25F8Turbocharger/Supercharger Bypass Valve C Control Circuit
- P25F9Turbocharger/Supercharger Bypass Valve C Control Circuit Low
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.