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.
Affected components
- Air pump b
- Air check valve
- Air pipes
Common causes
- High likelihood: Failed AIR pump motor or impeller
- Medium likelihood: Check valve seized by exhaust soot
- Medium likelihood: Corroded or cracked air injection pipe
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.