ECM Tire Size

Is there anyway to changed the tires size in the ECM with out using the dealer. They want an hours labor to changed the tire size. I am a diesel mechanic and know it only takes a few seconds to change. I want it so my DIC will display correctly and trans will shift correctly in tow mode.

Thanks
David

I had my truck at the dealer for an unrelated problem and i asked if they could correct the ecm so the speedo would be correct ect and they said they could only if the tires i had on there were an option from factory which of course they are not.

I had my truck at the dealer for an unrelated problem and i asked if they could correct the ecm so the speedo would be correct ect and they said they could only if the tires i had on there were an option from factory which of course they are not.

I got the same information. They could recalibrate the shift points, but could not do anything about speedo accuracy. They said I needed an aftermarket programmer to alter that, unless I wanted to purchase a new speed sensor but even then, it had to be for an tire diameter that was optional from the factory. Mine's an '02, don't know if the newer models are the same.

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