DTC P0420 Catalyst System Efficiency Below Threshold (Bank 1): DTC Detecting Condition

DTC DETECTING CONDITION AND POSSIBLE CAUSES

Item	Detecting Condition	Possible Cause
DTC Strategy	Oxygen storage capacity	Exhaust system B1S2 Catalyst converter ECM/PCM
Enable Conditions	Engine speed 1200-3000 RPM Engine load 15-50% Catalyst temp. (model) 470-7001: (878-1292°F) Purge factor (high load canister) < 12 Closed loop control
Threshold Value	Amplitude of downstream 02 sensor signal > 0.5
Diagnostic Time	60 sec
MIL ON Condition	2 driving cycle
* B1S1: upstream oxygen sensor/B1S2: downstream oxygen sensor