Odb Code P0420 ?????

[Mr Chips]

I know that ODB code P0420 means Catalyst system efficency below threshold on bank no. 1.

What does this mean?
What is causing the problem?
What is bank1?
What is the fix.
Thanks

Tahoe owner in distress

[maintainin76]

I had this same problem on my 99 Tahoe a while back. I think mine was P0430 which was the bank 2 side. Your Cat is probably bad and needs to be replaced. How many miles do you have on the truck? GM has a 8/80000 warranty on catalytic converters. I had both of mine replaced for free, no charge to me at all.

[Mr Chips]

It has 106,000 miles.
Hope it is something less expensive.
Thanks

[maintainin76]

Hate to be the bearer of bad news, but it probably is a bad Cat. It was explained to me that its doubtful that a bad O2 sensor or anything else could cause this code.

Here's my original post when I had the same problem:

http://www.automotiveforums.com/vbul...d.php?t=150604

[Mr Chips]

I was afraid of that. Guess I had better start looking around for the best price.

[99ssconv]

when the code sets your converter is bad, but what caused the converter to fail, i would find out what caused the failure before spending money on a new one. misfires are the number one cause of converter failures.

[Mr Chips]

"Misfires"
Do you mean like the spark plug wires are touching and firing two cyl. at one time?
I do want to correct any problem before changing the Cat.
Thanks for commenting, and making me aware of the root cause.
Hager

[99ssconv]

usually a misfire is a cylinder that is either loosing fuel or spark or possibly a vacuum leak to that cylinder,

[Mr Chips]

Originally Posted by 99ssconv

usually a misfire is a cylinder that is either loosing fuel or spark or possibly a vacuum leak to that cylinder,

If it were a fuel problem would the injector problem show up in the error codes?

The spark plugs and wires are about 8 months old.

Vacuum leak, I'll check the intake manifold bolts to insure tightness.

Any other ideas?

Thanks
Hager

[mega8man]

I have a questions on this topic if I am receiving this same code and i remove the cat. will it just keep appearing?

[g4life]

I have a 2002 chevy suburban with 180K It has a p0420 code. I changed out my plugs and wires and it the code went away but comes back off and on. the truck runs fine I have no loss of power and i dont have a missfire. I know it can be an o2 sensor but which one is bank one since i believe the truck has 4 sensors.