H3 Hummer PCM Programming


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After some research using the internet on PCM’s and Tuning, I found out that I don’t have the latest tune / reflash from GM for my H3’s 2006 3.5 L (211 CID) L52 I5 cylinder engine. I was able to check my vehicle by using a simple OBDII sensor I have and cross-referencing numbers using TIS website by entering the VIN number. I compared the tune number from my previous post P0455 & P0442 ECU Fault Log H3 Hummer where the Vehicle Calibration ID on my vehicle as 12606370. The tune 12606370‘s description mentions that it is for “New software to address customer complaint of the cruise being disabled.” Using my VIN number and selecting the option PCM/VCM Powertrain/Vehicle Control Module - Programming I’m able to see that the latest version is 12627884. The description of 12627884 says that it has “New software with driveability and fuel economy improvements achieved by decreasing the time TCC will be unlocked due to a misfire rough road event.”
12627884 New software with driveability and fuel economy improvements achived by decreasing the time TCC will be unlocked due to a misfire rough road event.
After reading about the improvements, Driveability and Fuel Economy, listed as a GM factory update I decided to get the newer tune from a GM dealership. Having driven on 12627884 for a few months now, I haven’t ever noticed and driveability changes. The Fuel Economy does feel a bit better, I’d say 5 to 10 more miles per gas tank. Since I didn’t quite get the changes I’m looking for, in the future I’d like to try PCM of NC tune for H3 Hummers for further tuning of my H3’s PCM. Hopefully, PCM of NC  will be able to deliver the “better part throttle response, towing, driveability, and more pep off the line” that they claim on their website. Along with accounting for the 35-inch tires on the speedometer.


  1. Hi Schwarttzy, where you able to get the PCM of NC unit installed for your h3?


    1. Schwarttzy Avatar

      Hey Dave! I went with the Super Chips FlashPaq F5 2845 tuner. The amount of options for customizing on my own is why choose it over PCM. I don’t really notice much from the tuning, but the modification to the shipping point is absolutely huge difference. I’ll be posting a blog article and a video about it.

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