Thread: CAT or O2 Sensor

Originally Posted by TDCRacing

Someone had this code on here just recently. And is the first time I have ever heard of this. They said they changed out the o2 sensor and it went away. I think it will be back though.



I have never seen an o2 sensor code that said catalist system low effeciency. And have seen a lot of o2 sensor codes.

I've seen this a lot. Especially when I worked for a dealer. The O2 sensor goes bad but not to the point that it trips its own code. It shows false readings that makes the PCM think the cat is bad.

If he has a stock cat, it's the O2 sensor.