P0420 - Volvo S40

Question

Changed the 02 sensor, changed the spark plugs, changed the ignition and ignition coils, changed fuel pump, changed the ring seals on the fuel injectors. What else could possibly causing the PO420? I\'m not even sure if this is the correction code because Volvo is never an option for the technician to choose so in most cases that choose Volkswagen.

Answer 1

HI there,

The P0420 code is for catalyst efficiency below threshold on bank 1. You likely need a new catalytic converter on bank 1. Based on all that has been replaced on the vehicle this would have to be the next step. This is a general code meaning it's the same for all models.