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Home >> Toyota >> 2004 >> Matrix Base, FWD, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 134 (Engine Control System Self Diagnostics - V6) >> Diagnostic Tests >> DTC P0420: Catalyst System Efficiency Below Threshold >> Possible Causes
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Possible Causes

WARNING: This page is about a different car, the 2003 Toyota Tundra. However, it is still accessible from the selected car via links, so may be relevant.

DTC is set when A/F sensor and heated oxygen sensor have nearly the same waveform pattern after engine and catalytic converter are at normal operating temperature and vehicle is driven. Possible causes are: