New member here, but old dude! I have a Ram 1500/5.7 Hemi/Auto trans.
It has 104k miles on it. No codes set.

However, when I hook up my Genisys Scanner (checking something else) the speed on the computer is significantly different than the speedometer. I.E.- at 60 mph indicated on the speedometer, the computer indicates 38mph. And, I am certain the speedometer is the more accurate indication.

When I first noticed this, I went to the Dodge house to get a replacement speed sensor. Told him I wanted the one that sent the signal to the computer. He didn't know which one and seemed to not be able to find out. So I resorted to online searching and still doing that.

Later, I got info (incorrectly) that it is the sensor on the rear of the trans. So, I bought one. That didn't make any difference. As many of you will know, there is a sensor on the trans input, one on the output and one on the rear end. So, I put the new one in the spot on the front of trans since putting it in the back spot didn't change anything. No change with the new sensor in the front or rear. Replaced the one on the rear end. No change.

Does anybody know what the heck this might be? How can it be that the computer thinks the speed is so low unless the sensor telling it that is bad? I am pretty sure that this error will affect the way the computer calculates all kinds of things, and it may not be so good.

Anyway, let me know if you have any kind of information. Or, ask me a question if I didn't give enough information.

Buddy

 

what's your tire size?

 

I would have to go look at the specific size, but it is the original factory 20" - No changes in size since new.