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Discussion Starter · #1 ·
2001 GMC Sierra 2500HD CCLB, stock tire size, EFI Live, 160K miles.
I'm wanting to recal my speedo and wondering if there is a cheap tuner/programmer or something out there that will do so (under $300?). I'm not looking for a tune or anything as I already have EFI Live. The speedo works fine and doesn't jump around like others I've heard, it's just a percentage off and will read around 90+mph while going 75 down the highway. Had stock tires when I got it and I'm still running stock. I've been using GPS to get an accurate speed but I'm tired of it racking up more miles than actual, messing with service intervals and calculated mpg. I have called 5 GM dealer service centers in my area and they they all tell me that they are not sure if they can recal and will have to charge $175 just to take a look..
 

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They know it can be done. I took my truck to my tuner and it took maybe 10 minutes start to finish and that included another adjustment . If you know what you'e doing and have access to the ECM with proper equipment, it can be done quite easily. No, I don't know personally how to do it.
 

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Was the speedo off before the tuning was done? Sounds to me like the tuner wrote the tire size wrong in the tuning if you're on stock size tires and always have been. 245/75/16 on it correct?
 

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Discussion Starter · #4 ·
It was off since the day I got it and truck was completely stock.

Sounds like maybe I should contact some tuners instead of the dealer. I just figured it would be a common thing for them to do.

Ron, do you remember about what you paid for the recal?
 

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Nothing. I drove to his place and he did the work while I looked around the place. I could have mailed the ECM to him and he would have returned it, but I made a trip out of it with a friend and hit a brewery on the way.
 

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When I went to 19.5" wheels, I used a Hypertech programmer to recalibrate the speedo. IIRC, the programmer is somewhere ~ $150 or less.

You will need a Windows computer to run the programmer as it won't work on a Mac. Don't ask me how I know this.
 
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