MDS won't activate over 60 mph.

[Jacob Authement]

I recently upgraded my Ram's wheels from 265 75 r17 to 275 60 r20. I noticed today that my MDS won't activate if I am traveling over 60 mph. It used to not activate over about 72. I also noticed that my odometer is 2 miles lower than my GPS. Has anyone ever had an issue like this?

 

[hehateme2812]

I recently upgraded my Ram's wheels from 265 75 r17 to 275 60 r20. I noticed today that my MDS won't activate if I am traveling over 60 mph. It used to not activate over about 72. I also noticed that my odometer is 2 miles lower than my GPS. Has anyone ever had an issue like this?

You my friend need to recalibrate for your new tire diameter. You need a tuner or the alfaOBD app.

Here is the link for the google play store https://play.google.com/store/apps/details?id=com.AlfaOBD.AlfaOBD

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[hehateme2812]

More info to prove you changed tire size throwing off your truck and mileage

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[Jimmy07]

I recently upgraded my Ram's wheels from 265 75 r17 to 275 60 r20. I noticed today that my MDS won't activate if I am traveling over 60 mph. It used to not activate over about 72. I also noticed that my odometer is 2 miles lower than my GPS. Has anyone ever had an issue like this?

The rolling resistance and the extra rotational mass of the taller and wider tires is what makes it harder for the mds to kick on.

 

[Ratket]

^^^mmmm go go gears!

 

[Krein]

hell, mine doesn't activate unless going down hill coasting but yes you need to recalibrate for larger wheels.


















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[Jacob Authement]

You my friend need to recalibrate for your new tire diameter. You need a tuner or the alfaOBD app.

Here is the link for the google play store https://play.google.com/store/apps/details?id=com.AlfaOBD.AlfaOBD

Do I also need a plug in adapter for this app? My truck did not come with factory bluetooth, so I am not sure how the app would interface with my truck.

 

[Jacob Authement]

Do I also need a plug in adapter for this app? My truck did not come with factory bluetooth, so I am not sure how the app would interface with my truck.

 

[hehateme2812]

Do I also need a plug in adapter for this app? My truck did not come with factory bluetooth, so I am not sure how the app would interface with my truck.

You absolutely do, has nothing to do with the radio and Bluetooth. It has to do with the obd2 port used to diagnose and program you truck, under the steering wheel

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[JV Ram]

I’m right there with you on this situation. I went from 17” rims to 20” rims. Called my local Ram dealer and they’re going to calibrate my truck for me. Costs about $100 for it.


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[indept]

Do I also need a plug in adapter for this app? My truck did not come with factory bluetooth, so I am not sure how the app would interface with my truck.

As hehateme2812 wrote yes you do. But not just any bluetooth OBDII interface, there are certain ones. You want to check which are recommended before buying.