Back in 2000 I did a experiment on several GMT800 trucks, gas and diesel. I used the Tech 2 to read the mileage on the cluster, PCM, and BCM. All showed a different mileage, within +/- 10 miles of each other.(On the same vehicle) I then swapped out clusters from truck to truck to see how the readings would change. The mileage would follow the cluster but not to the PCM or BCM. Each module has its own mileage programmed into it. Why the difference between the 3, I do not know. Remember you can buy a cluster with 0 miles on it for your GMT800, plug it in and go. If no one ever checked the other computers you would not know the true mileage.

 

GM is really cracking down on this right now, Im not sure what is stored where but I can tell you if you have a internal engine problem they will scan and snapshot to verify the calibration numbers match what GM has on file for the correct calibration numbers. There is a TSB out on the issue so dealers are aware and have to follow GM procedure for warranty repair.

 

Interesting info guys, thanks.

I am pretty sure I am getting some sort of tune for this truck though. I am stuck between Diablo and HP tuners. HP of course I can use it on the Cobalt too to squeeze a couple extra MPG out of it and firm up the shifts there too.

 

I am with 06Monte with this one, I am running the Diablo setup in my PCM for my 2008 Sierra. I have tried every way possible to change my calibration data that we check at the dealership for power adders. No matter what I do it does not change, therefore GM has no ideas there.... but I didnt say that.

We also have a customer at the shop that was worried about that with a 2009 LMM. He purchased the Diablo as well and no change... Hmmmm

 

what your "NOT saying" is awesome.
I am definitely gonna do a tune than....be it Diablo trinity or HP Tuners.

Thanks again guys for the info.

 

Nice!!!


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just got mine tuned with hp tuners, love it and u should also

 

I have read that there is a counter in the ecm, it's all over Camaro5.com.They will know if you put a different tune on the new vehicles.They will put a block on your VIN and they won't honor any warranty work.

 

my pcm is locked from the dealer and they said if we unlock it u will void ur waranty so i guess il go with another pcm and tune it , guess il try my chances on this one, cuz the hptuners cant access my stock files and cant take readings

 

That's strange I just got into and read a stock PCM just fine this morning on a 2010 Tahoe that I was tuning.