P0421 CODE
CITROËN C4 CACTUS

This is for cactus c4 2018

My EML came on and it showed that the car didn’t recognise the catalytic converter, citron said as first route of fix, to complete a software update. 6 weeks later the EML came back on and citreon then said it needed a new cat.   The car is only 4 years old and 27k miles…..cat is  not damaged in any way  soot levels and dbf all fine.  Turns out this is a known fault with these cars……that a technical services bulletin was issued……so don’t get tricked into paying for a new cat without checking this out.  Bit of a challenge, but end result it got covered under warranty!