Speedo Calibration

[white07gmc]

I just put a set of GMC 20's on my truck and my speedo is off by 3MPH. I called my local Chevy dealer and they want 150.00 to recalibrate it. They said they have to recalibrate some other sensors as well. Does this sound correct? seems like a high price to connect a programer and do it. I was thinking of just buying a hand held programer and do my self. what do you guys think?

[Doug_Scott]

Try another dealer. My dealer changed the tire size for me and did it for nothing. Took less than 10 minutes to do.

 

Now, there is something you need to understand as well. If your tire size is not listed, or if you change rear end gears, the dealer cannot recalibrate the speedo/odo. GM tech line will refuse to supply a new bin file that has the new gear set in it. That means if you put 4.10 gears in to replace 3.23 gears, the dealer cannot fix the speedo. You will need to either get a performance programmer (do not recall products, I only use BlackBear), or send your ecm to BlackBear for a tune and a fix for the speedo.

[white07gmc]

Thanks for the info. I have standard 275/55/20's so it shouldn't be a problem. I will try a different dealer.