if ordering a new truck

[John Dell]

After giving up on the Yukon xl I wanted to order[so many problems with these] I decided to order a 2017 2500HD. The dealer was sending me all the info he had. I noticed code 5M7 for just $10. It is speedometer recalibration for companies that need to change tires like railroads. I asked to put it on my order and it did. I know a lot of you like to change tire size, that's my plan. Don't know yet what it is but for the money just unlocking the ecm is worth it. Just throwing that out there for any of you that it may help. Same code may exist for other GM SUV's as well you will need to ask.

[Sledge8]

I did read some about this option a while back and it may not be real useful to you? It pertains to the Railroad using 19.5 " tires. To switch ECM calibrations it sounds like you still need to have a dealer do it. It also mentioned upping the weigh carrying capacity of the front end and allowing the TPMS to allow for 80 psi front tire pressures. I am not sure where I found this bulletin but I am sure you could Google "Hyrail Speedo Calibration" and find it. Hope you can use it for something? I have spent $10 bucks on worse things before.....

[John Dell]

You may be right. I never really looked into it as it came up at the last minute. For $10 I guess it couldn't hurt. My only real plan is to run 295/70/18 tires and adjust the front up a couple inches. Will see if it helps any.

[Z45]

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[RyanbabZ71]

They will only recalibrate for factory sized tires. They won't/can't set sizes that aren't loaded into the tech2's

 

 

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