Will a bad Catalytic Converter throw a check engine?
 

Keep getting a funny smell on my 07 x5. No check engine light, but curious if it will if the Cat is bad? Anyone have experience on this? Thanks in advance, A.J.

Yes, a bad cat will cause the check engine light to light-up.

Can you describe the smell perhaps more precisely than "funny?"

Sulfur or like a bad fart, perhaps? Rotten eggs? That's what I always smell from cats.

Should have an 8 year warranty on the cats...BUT, bmw wont replace them because they smell bad. You need to set a OBD code/CEL light

GL

A

Ard good thing you pointed that out. Many people forget the cats are extended beyond many of the MFR warranty periods.