I have a 2003 6 cylinder with 105K Miles. I just had the timing belt changed at the dealer. five miles from the dealership the Service Engine Soon light came on. When back to the dealer and they are telling me that I need both cats replaced and that it had nothing to do with the timing belt change. I find this hard to believe. What could happen in a timing belt change that could be causing this problem?

Perhaps they unplugged some sensor cables and did not properly plug them back in.

I would start with unplugging and re plugging in your O2 sensors and see where it goes from there.

There is nothing that goes between the two. Although you find that it is hard to believe there is nothing that is touched with the timing belt that has anything to do with the cats.

Clear the codes and see if they came back.

I started throwing a p0420 about 6 months ago, the cat is going but it does not cause any driveability issues. But I do have a set of Thorleys on the way.

x2 on checking sensor wires, etc...

But, this sort of coincidence DOES happen.


I was driving my jeep through a flooded area (ON a road), and RIGHT after going through a puddle, it just DIED.

I assumed the puddle wet the electrical, and did some drying, etc.

It turned out, by coincidence, that the fuel pump had just died, and the engine dying right after going through the puddle had NOTHING to do WITH the puddle.

IE: Shit happens.