Toyota Tundra Service Manual > Sfi System: Catalyst System Efficiency Below Threshold (Bank 1) (P0420,P0430)
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 (A/F) sensor, sends pre-catalyst information to the ECM. The second sensor, the Heated Oxygen (HO2) sensor, sends post-catal ...
