DTC P0420: Catalyst System Efficiency Below Threshold: Notes
WARNING: This page is about a different car, the 2004 Acura 3.5RL, 2003 Acura 3.5RL, 2002 Acura 3.5RL, and 2001 Acura 3.5RL. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
If some of the DTCs listed below are stored at the same time as DTC P0420, troubleshoot those DTCs first, then troubleshoot DTC P0420:
- P0136, P0139: Secondary HO2S
- P0141: Secondary HO2S Heater