p0430 code

[dwight]

I have a 2000 gmc sierra 4.8 ltr .I have replaced both o2 sensors on bank 2 side (passenger) and I still am getting a p0430 code.There are 380,000 klms on my truck.I am thinking the cat is bad .Any help would be greatly appreciated

Topic

[EricTheCarGuy]

That is actually what that code would indicate a problem with the catalytic converter NOT a problem with the O2 sensors. What I do is look at the O2 readings on a scanner while the engine is running, the front O2 should switch from rich to lean while in closed loop rather rapidly where the rear O2 should stay pretty much near .5v and remain fairly constant, if the rear O2 is switching similar to the front O2 it would indicate that the catalytic converter is not functioning properly hence it would set the code that you have.

[dreamer2355]

Welcome to the forums!

And i agree with Eric. Its always best to diagnose issues with vehicles than just throw parts at them in an attempt to fix it.

[Trcustoms719]

Yup, +1 on not trowing parts at it.

[BAXMAN68]

Bank 2 Catalytic converter has had it. I do believe that both cats are on the same Y-Pipe flanged to the muffler. That is a very expensive cat through GM. You might want to check out your aftermarket options

[Author]

Replies