Customer has just had complete exhaust system replaced by Kwik-fit (including cats, but not including the fore and aft Lambda sensors)

After a couple of days the MIL came on. On scanning I got "Cat efficency bank 2".

Now, I also found a small exhaust leak up by the manifolds and have advised him to go back to get this sorted before going any further with diagnostics.

(I Hope it is not the head to manifold gaskets! Other wise the poor chap will discover the true meaning of the word "Pain!")


Fore sensors seem to be switching correctly and at a good rate. Aft sensors are both at 0.46 volt with only small variation on blip and overun.

I am hoping that sealing the exhaust leak will solve the problem but if it doesnt how can I confirm whether or not the fault lies with the non-oem cats.


Its an expensive thing to have to recommend without having some way of knowing for sure, especially since doing so will result in agro with kwik-fit over the suitability of aftermarket cats! (I have already pointed out that it is normal good practace to replace sensors with a new cat, but since they seem to be working OK and cat failure was not the reason for replacement it doesnt seem strictly necesarry, especially since it would be another £400 or so)