How Can You Tell If The Catalytic Converter Is Bad?

[TheKingSim0n]

Thanks Drew

[j944]

I had two changed out on our MB and went w/ eastern universals at $130 apiece installed.
Its been a year and no issue's or codes.

[x5pdx]

How many miles do you have? I have an 04 4.4i w/ 45k miles and I kept on hearing this rattle under my car. My mechanic told me to call my dealership b/c it is warrantied up to 80k miles under emissions. I called my service advisor at BMW, brought it in and they fixed it at no cost.

[masterjohnson]

Originally Posted by TwinTurboGTR

I concur. BMW puts a sensor on everything so it will trip and SES light, but another way to tell is if you hear something rattle which means the guts of the Cat are loose or if the smell coming out of the exhaust is noxious like rotten eggs. That's usually a tell tale sign that something isn't right.

ouch. good thing i read a lot even though this thread is already old. there is no warning on my SES light but my exhaust really smells badder than rotten eggs. looks like i will be visiting my mechanic again before this year ends. i cannot let it like that because i used my ride everyday. i hope it wont get worst or else i need to buy catalytic converter.