MONITOR DESCRIPTION The ECM uses sensors mounted in front of and behind the Three-Way Catalytic Converter (TWC) to monitor its efficiency. The first sensor, the air fuel ratio sensor, sends pre-catalyst information to the ECM. The second sensor, the heated oxygen sensor, sends post-catalyst informat
INSPECTION PROCEDURE 1. INSPECT CHARCOAL CANISTER ASSEMBLY (a) Visually check the charcoal canister assembly for cracks or damage. If cracks or damage is found, replace the charcoal canister assembly. (b) Check the canister operation. *1 Connector *a Vent Line Port *b