Help with Speedometer Recalibration

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jareds

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I’m not sure how to get the speedometer recalibrated on my 21 Tahoe after putting 22” wheels on in place of the 20” it came with. Gm and my dealer will not help because they are not gm wheels.. any help is appreciated. The speedometer is about 3 mph off.
 

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Doubeleive

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IF and big IF there are any handheld tuner options for your vehicle then they generally have a option to adjust for tire size
pretty sure blackbear is not doing 2021's yet or they just won't be, you could look around at diablo or something-maybe I haven't looked myself
your options maybe limited GM is locking these down more and more. you could maybe try another gm dealer and ask them to set the wheel size to 22 instead of 20 just because they are not gm wheels doesn't make any difference but presume they are going to charge you to do that if they are even willing.
 

therealbofa

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Check out the Pulsar LT. Seems like the only option to disable afm on these engines with the 10 speed and has added features to disable ESS, change speed limiter and throttle sensitivity, and can recalibrate for different tire sizes. It isn’t cheap though.
 
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jareds

jareds

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So the dealer is willing to change it if they could but GM won’t give them the unlock code to change the programming, they suspect if they get another customer Tahoe in to get 22” wheels installed from GM they can use the RPO code from those GM wheels to call GM to remotely unlock both that vehicle and mine on two different calls. They’re not sure if GM will catch that the code was used twice but they’re going to call me to bring it in and try anyway. But I don’t know when that will be so I was hoping there was a solution out there I just hadn’t come across yet. So I’ll look into the Pulsar Lt and will have to go that route if GM catches the code being used twice. Just didn’t want to shell out more cash to make this right after almost $5k of wheels and tires!!
 

ljn21

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Check out the Pulsar LT. Seems like the only option to disable afm on these engines with the 10 speed and has added features to disable ESS, change speed limiter and throttle sensitivity, and can recalibrate for different tire sizes. It isn’t cheap though.
I don’t think it works on the SUVs yet, only the trucks.
 

Doubeleive

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part of the issue is GM doesn't want a hacker getting into the system now that there is more and more electronic (electric) controlled parts a hacker could wreck havoc on a vehicle, steal them, drive it away remotely, cause a accident remotely, that would be bad press for them.
they want to sell you a new toy and say go play with it nicely now.
 
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RST Dana

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I’m not sure how to get the speedometer recalibrated on my 21 Tahoe after putting 22” wheels on in place of the 20” it came with. Gm and my dealer will not help because they are not gm wheels.. any help is appreciated. The speedometer is about 3 mph off.
Measure total height on both wheels. (Top of the tires)If it’s the same, nothing is needed.
 
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