A P0420 diagnostic code on your 2020 Honda Ridgeline indicates that Bank 1's catalytic converter efficiency has fallen below acceptable thresholds. The Ridgeline's 3.5L V6 uses a dual-bank exhaust system with separate converters for each bank.
2020 Ridgeline Exhaust System
The 2020 Ridgeline uses Honda's 3.5L V6 producing 280 horsepower. The dual exhaust configuration means P0420 (Bank 1) and P0430 (Bank 2) are separate issues. Bank 1 is the rear cylinder bank near the firewall.
Common Causes
- Converter Aging: Efficiency loss over time and mileage
- O2 Sensor Issues: Bank 1 sensors malfunctioning
- Exhaust Leaks: Leaks on Bank 1 exhaust path
- Engine Misfires: Bank 1 cylinder misfires damaging converter
- VCM Effects: Variable Cylinder Management causing oil consumption
- Truck Use: Towing or heavy loads stressing converter