RachelJWalker

My check engine light came on ( P0430 ) Catalyst System Efficiency Below Threshold Bank 2 --- I am not convinced the cat needs replaced --- Need some suggestions ,,Thank you

EinST

Welcome to the forum. The reason you're "not convinced the cat needs replaced" is? Hang a scan tool and watch the bank 2 post-catalyst O2 sensor readings bounce back and forth by the same magnitude centered around 0.45V. If so, unless there's some sort of a rhythmic exhaust leak around that sensor (a highly unlikely scenario), the catalytic converter isn't doing its job.

MDTAHOE

99% of the time a converter code turns out to be a bad cat. Only use an OE replacement as most aftermarkets do not last long at all.

RachelJWalker

Thank you so much the reading are doing just as you described, The reason I didnt believe it is some times it will idle smooth and other times it is a little rough and I had someone say they think there is a sensor which will work some times and other times not so much so for the past week I have been pulling every sensor off and checking but not finding anything wrong , looking for vacuum leaks , checking plugs testing plug wires, Also I had a guy tell me if the cat was bad it would smell like rotten eggs and or rattle well I dont see or smell anything, But most of all the dealer wants 500+ for the Y pipe but I guess I will bite the bullet. Thank you so much for your response.

RachelJWalker

Thank you for your response I have looked and tested every sensor from the MAF to the post O/2 all checks good. so I guess all that is left is to go to the dealer and ask for a credit application. again thank you.

in2pro

Rattling would only occur if the innards of the converter actually were broken, I think the smell is when the converter IS doing its job but in overtime...
The converter is most likely blocked due to a poorly tuned engine, lots of miles or poor fuel quality...