DTC    P0420    Catalyst System Efficiency Below Threshold (Bank 1)

MONITOR DESCRIPTION

CATALYST LOCATION

CONFIRMATION DRIVING PATTERN

CONDITIONING FOR SENSOR TESTING

INSPECTION PROCEDURE

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0420)

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE INJECTION VOLUME FOR A/F SENSOR)

CHECK FOR EXHAUST GAS LEAK

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE EGR STEP POSITION)

INSPECT EGR VALVE ASSEMBLY

REPLACE EXHAUST MANIFOLD CONVERTER SUB-ASSEMBLY (TWC: FRONT CATALYST)

CHECK FOR EXHAUST GAS LEAK

CHECK FOR EXHAUST GAS LEAK

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE EGR STEP POSITION)

INSPECT EGR VALVE ASSEMBLY