Speedometer calibration 2019 RAM 1500

[jimh4662]

Well, two dealers and two local garages cannot calibrate the speedometer. Since I increased tire size to 275 60-R20 my speedometer reads approximately 3 mph faster than stated on speedometer. Actually 2.27 mph. Anyhow nobody seems to be able to adjust for tire size. One Ram dealers tech said a service contract needs purchased then your VIN is tag as able to be adjusted for tires and gearing. Their calling Chrysler to see if there is a work around.
Anyone have any technical advice to challenge these dealers please advise.

 

[iLLeStEyECoN]

You don’t need to purchase a service contract to have them adjust parameters in the computers...


Sent from my iPhone using Tapatalk

 

[jimh4662]

They plugged in there Mopar terminal and no function was available to change the tire size

 

[iLLeStEyECoN]

They plugged in there Mopar terminal and no function was available to change the tire size

I doubt they’re selling hundreds of trucks that come off the lots with aftermarket rims across the country with incorrect or intentionally inaccurate speedometers.


Sent from my iPhone using Tapatalk

 

[jimh4662]

Agreed. That's not the point of this discussion. I added larger size tires. Ram and Wranglers have the options to add larger tires. This changes the speedometer to a faster speed. There's been a bunch of tire size increases on the new rams. I was hoping to gain knowledge to advise the dealers on how to fix.

 

[tidefan1967]

Agreed. That's not the point of this discussion. I added larger size tires. Ram and Wranglers have the options to add larger tires. This changes the speedometer to a faster speed. There's been a bunch of tire size increases on the new rams. I was hoping to gain knowledge to advise the dealers on how to fix.

I would check with Hypertech, Flashcal and Superchips and see if they have updates for the 2019's yet. Then I would buy a used unlocked programmer and then update it online and it should cover the new RAM. I wouldn't mess with the dealer for anything but free and absolutely necessary warranty work. Just sayin.........

 

[ksn240]

Hypertech has a programmer available that does work for the 2019s. There is also a Pulsar out for the 2019s that can change tire size and also has a few canned tunes.

 

[runamuck]

they should be able to flash the computer. when I bought my 2019 someone at the dealer had put on 22" wheels and touring tires. I had em switch back to the 20" wheels and tires on the window sticker and they did and said they also reflashed the ecm for the correct size.

 

[iLLeStEyECoN]

Agreed. That's not the point of this discussion. I added larger size tires. Ram and Wranglers have the options to add larger tires. This changes the speedometer to a faster speed. There's been a bunch of tire size increases on the new rams. I was hoping to gain knowledge to advise the dealers on how to fix.

I’m not sure it’s your responsibility though. They’re obviously incompetent. If they can’t flash your tire size, you shouldn’t trust them doing real work. They’ve changed the computers since I was a tech so I can’t advise on that. My bigger point was that they’re either lying or not worthy of helping you much longer.


Sent from my iPhone using Tapatalk

 

[stimpy433]

If the 5th gens are like the 4th gens, the dealer can only change tire sizes based on what was available for the truck. They can't flash for non factory option sizes. You have to use an aftermarket tool to change if you went to a custom size.

 

[iLLeStEyECoN]

If the 5th gens are like the 4th gens, the dealer can only change tire sizes based on what was available for the truck. They can't flash for non factory option sizes. You have to use an aftermarket tool to change if you went to a custom size.

How are dealerships selling these trucks with oversized, aftermarket rims, then? I am curious if they’re not adjusting the speedometer.


Sent from my iPhone using Tapatalk

 

[stimpy433]

The last truck my dealership customized with a lift and big tires they included a hypertech unit with it that they had used to adjust for the bigger tires. Not saying all dealers do that, some may do nothing just as some owners do nothing as they don't care about the speedo being off a few MPH.

 

[tidefan1967]

If the dealer is willing to do it for free or like $50 or something by all means let them do it. If they want $100 plus see my first comment ^