This is a "how-to" reprogram the BCM and ACM in the Jeep Liberty to correct for different size tires. Please note that this can only be accomplished via a DRBIII. This procedure only works for 2005 and older Jeep Liberty's, for 2006+ a starscan instead of the DRBIII is required. For those in the Colorado area wishing to have this done I do offer DRBIII programming. Please contact me here for programming cost and availability.

From the main menu, select #1, DRBIII standalone.



Select #1, 1998-2007 Diagnostics.



Select #1, All.



Select #3, Body and Interior.



Select #1, Body Computer.



This will display after first detection.



Select #9, Miscellaneous.



Select #4, Program Tire Size.



Stock is set at 725/mile for the odometer, press Enter to modify.



Options 1-5 select the revs/mile of the stock sized tires, use 6 to manually enter revs/mile.



Use the up and down arrows to select the desired revs/mile, then press enter.



It will now show the new revs/mile. The BCM and odometer will now read correctly. The speedometer now needs to be corrected.



Hit, "Back Page" until you come to this screen. Then select "Anti-lock Brakes"



This will then display:



Select #9. Miscellaneous



Select #2. Set Pinion Factor.



Press Enter to change.



Select #6. Other.



Stock revs/mile is 721, press up and down arrows until desired number is reached, press Enter when done.



Press Enter again to accept new value.



Tire Size has already been set in the BCM.



Programming done. Confirm new revs/mile with GPS or other speed measurement. Reprogram as needed. Typically some trial and error is required to get an exact speedometer reading. For example, the calculated revs/mile for a tire might be 639, but the speedometer is most accurate at 670 revs per mile. Typically leaving the odometer revs/mile slightly lower will insure the odometer does not read higher than actual, though the calculated fuel economy will be slightly off.

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