How to Fix a Honda P0420: Catalyst System Efficiency Below Threshold Bank 1
Whyingo · 264K views · 3:04
Skill Level
IntermediateTime Required
Half dayEstimated Cost
$200–500Equipment
Honda Civic 10th Gen (2016-2021)Permit Required
NoTools Needed
Jack and jack stands, Socket set, Wrench set, Screwdrivers, OBD-II scanner, Safety glasses, Work glovesDefinition meaning and fixes for a Honda P0420: Catalyst System Efficiency Below Threshold Bank 1