Ok, so I got lucky enough to get access to a fancy, full-fledged, $3500 diagnostic reader/programmer, hoping to finally correct my speedo to compensate for my changed tire size...

Ehhh! Wrong! For some reason I can't access the part of the computer that controls this! Does anyone have any advice? I took it to the dealer before and they said they couldn't communicate with the computer and that it was bad... But if the computer is bad, why doesn't the truck have problems running? I don't get it...

Anybody else had this problem or know of anything to do?

 

I keep thinking that the 97's need a speedo gear change (in the tranny) but Hypertech's site says that they can be fixed with their programmer. I was almost certain that the RWSS started to be used for this purpose (speed calculation) in 98 with the introduction of the electronic odometer. Huh ...