Code P0420 Catalyst System Efficiency Below Threshold (Bank 1) P0430 1GR-FE

In order to detect any deterioration in the TWC, the ECM calculates the Oxygen Storage Capacity (OSC) of the TWC. This calculation is based on the voltage output of the HO2 sensor while performing active air fuel ratio control. The OSC value is an indication of the oxygen storage capacity of the TWC. When the vehicle is being driven with a warm engine, active air fuel ratio control is performed for approximately 15 to 20 seconds. When it is performed, the ECM deliberately sets the air fuel ratio to lean or rich levels. If a rich-lean cycle of the HO2 sensor is long, the OSC becomes greater. There is a direct correlation between the OSCs of the HO2 sensor and the TWC.

DTC P0340 P0342 P0343 P0345 P0347 P0348 1GR-FE

DTC P0340 Camshaft Position Sensor Circuit Malfunction DTC P0342 Camshaft Position Sensor "A" Circuit Low Input (Bank 1 or Single Sensor) DTC P0343 Camshaft Position Sensor "A" Circuit High Input (Bank 1 or Single Sensor) DTC P0345 Camshaft Position Sensor "A" Circuit (Bank 2) DTC P0347 Camshaft Position Sensor "A" Circuit Low Input (Bank 2) DTC P0348 Camshaft Position Sensor "A" Circuit High Input (Bank 2)
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