The PCM has all factory available tire sizes pre-programmed into it. A
dealer can only change the tire size to one of these - their tool simply
tells the PCM which number to use. A non-factory size can't be used unless
you get a custom flash OR you recalibrate the sensor.
I would be very, very wary of making any change to the sensor and/pr the
signal it sends to the PCM, as this sensor is also used by your ABS
system. I also wonder how they can have "one size fits all" with such a
device. Possible I'm sure, but it may be a compromise.
"Victor Carrola, Jr." wrote:
> My 2001 4c4 Quad came with 265-70-16s from the factory. I have since
> replaced the tires with 265-75-16s. This puts my speedo off by about
> 3%.0 Not too big a deal, but it throws off all the calculations on my
> overhead computer in addition to the speedo and odometer being off.
>
> I went to the dealer today to have them adjust the PCM for my new tire
> size. Problem is the dealer says the PCM only has three available tire
> selections: 215-75-15, 235-75-16, and 265-70-16. So your speedo will
> only be correct if you use one of the listed tire sizes and have your
> PCM programmed appropriately. After doing some research today I found
> an interesting device that may correct my speedo
> http://www.abbott-tach.com/era.htm. for $145. I had alerady checked
> with Hypertech, but they don't have a programmer for the 4.7 Dakota.
>
> I wanted to know
> Can anyone confirm if these are the only three tires sizes available to
> set the PCM?
> Has anyone used this ratio adapter or a similar device?
> Any other solutions?
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 11:59:54 EDT