Reflash ECM

[wolfpack]

i have a 2008 Yukon XL that was bought used in NC. It was originally sold in CA, so the ECM software has the ridiculous emission thresholds in it. The check engine light comes on ALL the time and it's usually code 0430 (cat system efficiency below thresh). It's a major PITA. I've had the cats replaced twice, O2 sensors repositioned. I actually feel bad for the muffler shop that did this because he took a major loss on it (good guy)! I paid for two NC cats and we've been through 4 cats now, on his dime.

Can I just reflash the ECM with non-California code to stop this nonsense? How do I do that?

 

[calif phil]

Someone can reprogram the truck to do away with the rear 02 sensors. But it is not just a California thing. All stock obdII vehicles have downstream sensors. I have found most aftermarket cats to not perform up to OEM standards. If you do not have emission testing required by your state then you can find someone to tune your ECM and disable the downstream sensors. I did that with the LS swap in my '69 GMC.