Comment on P0420 – Catalytic converter system, bank 1 -efficiency below threshold by Robert

R

Robert

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#1
Make: toyota
Model: prius
Year: 2005
Miles: 287000
Engine: 1.5l

Fuel injector failure, replaced injectors, upstream and downstream sensors now throwing p0420 catalyst below threshold. Is it likely that the failing injectors resulted in this ? Any suggestions on how to proceed with diagnosis?
Thanks

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grcauto

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#2
The upstream sensor has nothing to do with the cat code. It's only used for fuel control. The post cat sensor is used to monitor the health of the catalyst. If your injectors were over fueling it most likely destroyed the catalyst.