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speedometer calibration ?????

DieselRebel

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So just had this done today...It broke my park sense also just like my Alpha OBD did so no benefit and out $125 plus tax. Said they will call Chrysler again to see if it can be fixed on their side and rebuild the BCM config again. If they can't fix it, I will be asking for a refund. At least the speedo is correct now lol.
I used Alfa OBD to adjust the tire size and my park sensors work same as before
 

ramchaser

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I used Alfa OBD to adjust the tire size and my park sensors work same as before
What tire size did you go to and what size in mm did you set it to in Alpha? Anything over 2658mm disables my park sense in Alpha.
 

DieselRebel

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What tire size did you go to and what size in mm did you set it to in Alpha? Anything over 2658mm disables my park sense in Alpha.
I put in 2692 and park sensors work same as before. My tires are about 33.75" with tape measure, but are 285R75.

What BCM are you using? I used DT My 2020 Powernet
 

ramchaser

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I put in 2692 and park sensors work same as before. My tires are about 33.75" with tape measure, but are 285R75.

What BCM are you using? I used DT My 2020 Powernet
I used the DT2019 Powernet on mine...Might see if it will talk using DT2020 Powernet. Alpha for Android is $50.
 

Doofus74

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When you said it broke the park sense, what are the symptoms, and what size tires are you running?
It ”breaks” the park sense by turning the front and rear sensors off. You can push or cycle the switch but it stays off and wont engage. When i used the hyper tech that came with the truck, I could flash back to stock and the sensors would work, flash back to correct the speedo and boom, every time brick the sensors.
 

Doofus74

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So I bought a new truck. Lady smacked my new 1500 and they “fixed” it. Anyways bought a travel trailer and decided to go get this blue 2021 ram 3500 diesel pictured. So back to lifted and rolling!!! Now just need to figure out the speedo issue again and sensors. Anyone have luck? I see some used my quote from earlier this year, so must still be issues for some and the park sensors while calibrating for tires. I have 37x12.50x20. I took the 37x13.50x20 off as the rubbed while back up at full lock in reverse.
 

jjmcmanu

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So does this software change impact transmission shifts or just speedometer? I don't really care if my speedometer is off a little, more concerned that my transmission feels like it's shifting different than before. I only have 33" tires but they must be much heavier than stock.
 

Idahoktm

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So does this software change impact transmission shifts or just speedometer? I don't really care if my speedometer is off a little, more concerned that my transmission feels like it's shifting different than before. I only have 33" tires but they must be much heavier than stock.
Recalibrating your speedometer might have an impact on shift points but it doesn't change them. Your tires are 34's, not 33's and yes, LT tires are quite a bit heavier than the stock tires. If you have 3.21 gears, it will be more noticeable. Your speedometer is off more than a little IMO and worth recalibrating.
Screenshot_20220219-145831_Chrome.jpg
 

Chippy

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The shift points are very affected by tire size. When I put my 35’s on I used the Tazer and it fixed it up the speed and the shift was spot on. My sensors work the same. Tazer size to match tires was 34.76 or close speedo is a better match now confirmed with gps than when stock 18,s were in the truck.
 

Jr22

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I just added a 4inch lift and 35's on my 20 limited 3.21 gears, and the size is effecting the truck quite a bit. It keeps up and down shifting between 7th and 8th when I am on cruise control at freeway speeds. I am currently on the hunt for a ram/dodge dealer that is willing to recalibrate my truck. Two local dealers around me are telling me its not even possible. If anyone has any leads to a Norcal or even Socal Dealer that is willing to do it please let me know.
 

ferraiolo1

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With 3.21s and 35s you’re going to have that constant shifting to an extent.


Sent from my iPhone using Tapatalk
 

Chippy

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I have the lower rear gear but based on how much I noticed the shift points improved I’m not convinced it’s a power issue but a what the computer sees and does with it. Taser is cheap and has a bunch of extra functionality. I would rather pay a bit more than waste time with dealers.
 

Mikeg22

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I am having 34" tires put on my truck, I asked them to calibrate the speedo, they said no problem it's $150. I have seen the same price quoted elsewhere in this forum. I think it opens some kind of work order/ticket. It is good for 6 weeks. That is so you can't come back next year and ask them to do a different size without paying again. I would just call your local service department and ask. My local one would not do it when I asked but the one I am getting the truck from was all over it. So you might have to call around a little. As far as having the body control module updated I also heard about that in this forum as well. I guess some DIY attempts don't work so well with the sensors, like the Tazer if the tire size is too much. Best to find a dealer that knows what they are doing to, because a 35" tire is not really a 35" tire when it rolls, its more like 34.4". I am not an expert by any means but $150 for a properly calibrated truck seems like a good idea, and other forum members have said the same. Check this out.

I asked my dealer about doing it and they said they couldn’t do it. Dodge didn’t have the update for the 2021 yet to beable to do it. I called another dealer they wanted 250 to calibrate my speed odometer. It’s crazy why one can and another can’t.
 

JerryBsizzle

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I asked my dealer about doing it and they said they couldn’t do it. Dodge didn’t have the update for the 2021 yet to beable to do it. I called another dealer they wanted 250 to calibrate my speed odometer. It’s crazy why one can and another can’t.
My dealer did my 2021 in March of 2021. They lie
 

Jr22

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I asked my dealer about doing it and they said they couldn’t do it. Dodge didn’t have the update for the 2021 yet to beable to do it. I called another dealer they wanted 250 to calibrate my speed odometer. It’s crazy why one can and another can’t.
Yea it just really depends on who you get on the phone! Every single dealer has accesses or the mopar dealer page to change the parameters of the vehicle to reprogram it. It just depends if that employee knows any better. Hell I had one of my local service manger tell me it wasn't even possible! went down to the next dealership they did it no problem. Just think of it as you wouldn't want to bring you truck to a dealer who doesn't even know what they are talking about anyways.
 

TUBBS

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I am running 35x12.50r20's and had the dealer flash my speedo yesterday for $125. Everything is working great. I did a test on the way there. At 40mph I was in 5th gear @ 1900 rpm. After the flash at 40mph I was in 6th gear @ 1300 rpm. They actually measured the tires, which are close to 34 and used the actual size. Just my 2 cents.
I would like to know where this dealer is at?
 

ChrisSpeed

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Have a ram 1500 2023 ecodiesel with 35’s. Has anyone had any luck with the Ram dealer programming the ECM and it worked?
 

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