P0431 MAZDA Warm Up Catalyst System LH Efficiency Below Threshold

Possible causes – Warm Up Three Way Catalytic converter deterioration or malfunction– Exhaust system leaks– Loose front or rear HO2Ss– Faulty front heater O2 sensor– O2 sensors harness is open or shorted– O2 sensors poor electrical connection Tech description As the code description implies the P0431 code means that the vehicle’s control module has detected…