ripgtp97

iTrader: (2)

I looked it up on 2 sites but i'm still wondering is it just the rear o2 sensor, or is it the cat?

I'm going to be replacing the y-pipe anyway, but until i have all the money, hoping an o2 sensor can hold me over

joecar

RHS cat.

P0420/P0430 means the respective rear O2 is responding too soon wrt the front O2...

i.e. the rear O2 is fine, the catalyst is gone (literally).

eseibel67

iTrader: (10)

Problem could be something other than the cat, including the passenger side downstream O2 sensor:

http://www.aa1car.com/library/p0420_dtc.htm

69LT1Bird

iTrader: (1)

The diagnostics are pretty cut and dry for that code.

P0430

SLOWWZ28

iTrader: (1)

Its the cat! If it is a high flow cat it is probably not bad they just are not good enough factory peramiters to pass the cat eval and u will have to eliminate the code from the tune. If it is the factory cat the cat is bad! That code is set when the down stream o2 is switching to much! When o2 sensors go bad they stop switching. Dont waste ur cash on a sensor! If ur installing high flow cats or removing them u need to remove the cat codes anyway p0420 and p0430. So regardeless the sensor would de a waste!