How to: Change Tire Size
This option allows you modify the programmed Tire Height. When larger tires are installed, speedometer will show incorrect values, also fuel consumption will be less accurate. If tire size is not set correctly car may loose some performance, and transmission shifting is incorrect on automatic gearbox.
* When you change vehicle settings Engine must be OFF and ignition set to RUN
New tires setup process
Now it's time to test new settings.
When procedure is completed turn ignition to off leave the car and close the car for 5 min. All computers should now go to sleep.
After 5 min, start the car and do a test drive and check if all is fine, if you have any problems. Check troubleshooting section.
My speedometer is not working and i have check engine light.
This is rare but it may happen especially when engine was running during adaptation.
Procedure to fix speedometer:
- Open “Quick Diagnostic" page on main page and tap “Trash" icon. Engine must be OFF and Ignition must be set to RUN (usually second key position).
- When code clear procedure is completed turn ignition to off leave the car and close the car for 5 min. All computers should now go to sleep.
- It will clear all codes and restore normal operation.
Start with key in run position
Start JScan app
Go to Tire Size adaptation and select desired tire size
Press “GO" and it should take a couple seconds to complete.
Once done, cycle the ignition key to Off then back to Run, at this point you can get all kinds of lights on the dash, so then you need to do the ABS module initialization.
Select ABS initialization procedure from the list and follow the instructions.
When procedure is completed go back to the drop down and select Static ABS ECU initialization
Press start and wait to complete
Go to ABS Module and clear all faults on ABS module!
Then cycle ignition key.
Clear the faults at Body and Power Train, after complete clear faults in the Body control module and the engine.
Once complete start your ram and take it for a spin.