DTC    P0420    Catalyst System Efficiency Below Threshold (Bank 1)

MONITOR DESCRIPTION

CONFIRMATION DRIVING PATTERN

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0420, P0430)

CHECK FOR EXHAUST GAS LEAKAGE

INSPECT HEATED OXYGEN SENSOR (RESISTANCE)

PERFORM ACTIVE TEST

REPLACE CATALYST CONVERTER (BANK 1 OR BANK 2) AND FRONT EXHAUST PIPE