Trouble code P0420 means: Warmup Catalyst System Efficiency Low (Bank 1)
When this code come out may be haven no enough warm up on the catalyst is efficienecy the vehicle has an exhaust leak
P0421 : Warm up catalyst efficiency below thresh hold bank 1
P0421 : Warm up catalyst efficiency below thresh hold bank 1
P0421 code = Warm up catalyst efficiency below threshold, Bank 1
Trouble code P0421 means: Catalyst Efficiency Below Normal (Bank 1)
Trouble code P0421 means: Catalyst Efficiency Below Normal (Bank 1)
Trouble code P0421 means:Warm up catalyst system efficiency below threshold
Trouble code P0421 means:Warm up catalyst system efficiency below threshold
Trouble code P0421 means: Catalyst Efficiency Below Normal (Bank 1)
Trouble code P0421 means: Catalyst Efficiency Below Normal (Bank 1)
Passenger side and after the catalytic converter O2 sensor.
if you have more than 60K miles start by replacing the Oxygen sensor(s) that is(are) installed after the catalytic converter(s).