What possible problems could arise from switching to 20' rims, the door sticker shows the truck had 245/70R17 rims but has 20' on it now Please help if you can. Also when the scanner is plugged in it shows non drive wheels 1/2 variance or differential, Abs light is on and throttle response is poor. 2004 dodge 1500 hemi 2wd,has 275/60R 20 rim and tire, thank you in advance

 

How does the computer know what size the tires are? or the rims for that matter?

 

ummmm no problems since they come with factory 20" on them....try cleaning the throttle body and doing an injector cleaning for the poor throttle response, reprogram the tire diameter in the truck and see what happens from there

 

By taking rotation readings, via the ABSbrake sensors.They can't tell exactly what size they are, but they can tell if one is different then the others, or if the fronts are different then the rears.

Check and see if your front and rear tires are the same size and brand.

It almost sounds as if your front tires are a different size then the rear. (Front = non-drive wheels) This isn't a problem, until you hit the brakes and the larger tires are spinning faster then the smaller ones, and the ABS is confused and tricked into thinking the vehicle is skidding.

ABS sensors are used to monitor wheel speeds for braking purposes, then sends the info to a "computer". Unless programmed for it, (Dodge Prowler or Viperfor example) all the tires have to be approximately the same size/height, with a small variance for wear, or brand difference or the computer picks up on it.

It's not that the computer "knows" what size rims that you have, but knows if the overall diameter is different on one axle, then on another.

Check tire size....first.

I have a friend with an 03 QC, that changed from 17" to 20" with no issues, or reprogramming.

Do you have a Superchips Programmer?

 

I did not have any problems going to 20's from 17's other than my 3.21 gears aint helping, and I never thought that the computer would pick up that stuff . . . amazing. I hope it dont pick up the smell I leave after eating cuban black beans or else is calling AAA for me.

 

Only if you have a complete failure of your "****"
(Air-**** Separator Sensor.)

 

[sm=icon_rofl.gif]

 

How do you change the size in the computer for the tires that are brand new and all the same size

 

You will either need to take it to a dealer or pr purchase an aftermarket programer.
Many of the new programers allow you to calibrate you speedometer for new tire sizes.
As for swapping to the 20's from the 17's, you may notice a little loss in power as the tires that come on the 20's are actually 2.5 in. taller.

 

My 03 came from the factory with 20's, but the door sticker shows the 17's