DTC codes, service engine

[Chanks7]

Any GM techs here or anyone else who has dealt with this code. A P0420, catalyst eficiency low bank 1. Anyone know what this means?

[Cool Zr2]

Means your driverside cat needs to be replaced.

[Import Hater]

Or the downstream O2 sensor could be bad, and throwing a misleading code.

[C1500]

I just got this same code, Autozones "Code Book" says that the EGR valve is bad, I cleaned it out yesterday & still get the code. All the O2 sensors have been replaced in the last month. (had O2 codes last month) From what you say it's my cat. Gee could that be because I gutted the inside of mine because it was rattling?

[Jeremy WI]

Gutting the cat would cause that code

[C1500]

It was worth the shot before having to spend the money on a new one. $400 for a cat is crazy, Who's bright idea was it to make the "Y" pipe & cat all one unit?

[J&Ks91]

instead of spending the money for the new cat get you the O2 sims. these are oxygen simulators to fool the computer into thinking that the catalytic convertor is working properly. you can find them in a jegs or summit catalog. they are close to 100 bucks for a set.