P0421 OBD Trouble Code

2 results found

P0421 - Generic
Type Powertrain - Auxiliary Emission Controls - ISO/SAE Controlled
Description

Warm Up Catalyst Efficiency Below Threshold

Location Bank 1
P0421 - Ford
Type Powertrain - Auxiliary Emission Controls - ISO/SAE Controlled
Description

Catalyst System Efficiency Below Threshold Conditions

Cause

Engine running at steady state highway conditions for 5 minutes in closed loop, then the PCM detected that the rear HO2S switch rate was too high

Try also: http://www.obd-codes.com/p0421