Hello all, in addition to the starting issue I just posted about here (which I believe to be resolved thanks to the helpful folks on here) I also have a P0420 code on my 2003 V40. Says catylitic inefficiency bank 1. Or something to that effect. It has come to my attention that this car has two cats however. Does bank 1 mean it's the first cat and that should be replaced? The car has a stutter under hard acceleration when reaching higher rpms. I'm not sure if that is related to the fuel regulator or if it's related to the catylitic converter.

 

V6/8s have two banks, your 2.0 only has bank 1. The code is saying the ECU is not getting the expected differential between the front and rear o2 sensor. That can be caused by fuel trim issue (ie fuel pressure, vaccuum or exhaust leaks), worn plugs/coils (most likely these issues will throw other codes), O2 sensor or the cat itself. You didn't say how many miles on the car. You may want to throw in some new plugs, check the fuel pressure levels and check around for intake or exhaust leaks. I'd think that a leaky fuel regulator would also cause hard start ups - but can bleed extra fuel into the intake... check that by pulling off its vacuum line to see if it leaks any fuel out (start it first then shut off to build some pressure in the rail).

 

It does need a fuel pressure regulator. If fixing that would cure the hard starting and this code that'd be great!

 

I'd start there then reset the codes and see whta comes back.