P0420 Ford - fiesta 2011

Question

Where is the location of bank 1 O2 sensor? My code reads: P0420 catalyst system efficiency below threshold bank 1. Thank you. Patty

Answer 1

Hi Patty,

This code is for the catalytic converter. If you are in the US, this part is covered with an 8yr/80000 mile federal warranty. If you fall within the mileage the dealer is required to cover the repair.

As for the O2 sensor question, the car has 2 one in front of the converter and the other behind the converter. in this case you would want to replace the rear sensor behind the catalytic in the exhaust pipe.