Possible Causes
WARNING: This page is about a different car, the 2003 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.
Possible causes are:
- Exhaust gas leakage
- HO2S (RF, LF) malfunction
- Looseness of HO2S (RF, LF, RR or LR)
- PCM malfunction
- WU-TWC deterioration or malfunction