Ford P0421 OBD-II Trouble Code Definition: P0421 Warm Up Catalyst Efficiency Below Threshold Bank 1 P0421 Ford OBD-II Trouble CodeDescription: OBD Trouble Code P0422 Main Catalyst Efficiency Below Threshold What does the code mean? OBD-ii Code P0422 definition: The optical sensor provides a high resolution signal to the Powertrain Control Module (PCM) by counting pulses on […]