redbird555

Hey guys I have the p0420 code on my 07 car only has 21k on it so I highly doubt its a bad cat. My local dealer wants 150 bucks to flash the code which imo is stupid since its not a wear item, its glitch by gm on all car models, but I digress...

So my question is can anyone help me out here that has had the update done and send me an hptuners file of the car after the changes were made??

schpenxel

"flash the code". What does that even mean?

HPT doesn't have access to everything so just comparing a newer OS's tune vs. yours very well may not show anything of any significance. The better idea is to just set the code to do not report and be done with it

INTRCUL

There's a TSB to specifically address the 0420 or 0430 code by flashing the ECU to widen the efficiency range of a cat and not throw the code. It should be covered under the 8yr 80k miles emissions warranty, but you're probably past the 8yr mark right? I literally just had this done on my 2011 last Friday and the dealer refused to code it as emissions work and put it under my GMPP extended warranty. If I didn't have that they would have charged me and I would have had to print the TSB elsewhere and show them what they refused to read on their computer screen. The TSB has instructions on how to code it as 0.4hrs labor under emissions warranty.

If you are out of the 8yr emissions warranty just pay for the flash. It's a lot cheaper than replacing the cat. I've also read the 02 sensor past that cat might be acting up and falsely throw the 0420 code as well.

Sox-Fan

Does anyone know the number of the TSB or how to look it up?

erick_e

I looked in Chilton and can only find where it applies to 07-09 LS7s and 09-13 LS9s. Doesn't mean that there isn't one for LS2/LS3 just that Chilton doesn't have one listed.

TSB 14-06-04-001A for LS9s
TSB 09-06-04-011A for LS7s

INTRCUL

So the dealer claimed they flashed my ZR1 but the code came back after the usual 4 or 5 cold to warm driving cycles. Back to the drawing board...

The Grand Sports should be covered by this TSB as well, but I'm not sure if it's just the hand built dry sump LS3s or not.

"Flashing" just means they reprogram the ECU and widen the range of what is considered "acceptable" before it throws a code. It's kind of cheating, but saves GM a lot of money by not having to replace a cat that has lost some efficiency, but hasn't completely failed yet.

schpenxel

I'd just have the code turned off

erick_e

The LS9s are also supposed to get the 2012+ four catalytic converters with the TSB.

Sox-Fan

I have a stock O8 LS7 with 36k miles and a P420. Before I go shutting anything off or replacing parts I will want to look into this a little bit. Sometimes a little information goes a long way. Sometimes not, but it can't hurt to learn more.

Thank you for the number.