Dealership can now reprogram / calibrate speedometer and odometer for bigger tires

[Fred]

+1 -- I've been searching for a couple days. It looks like the only way is via a programmer like FlashCal. I just really hate the idea of pulling plugs out of my system to install the bypass for the programmer. Plus $250 - $350 to be able to change tire size and tpms threshold is pretty steep. I know some are gonna say that the programmers have other features. But honestly I don't need a "light show" when I'm out in the woods. Very bitter about this. Don't trust the dealership and don't want $250+ device that could potentially brick my Jeeps computer.

And the programmer is "married" to the vehicle once you plug it in is what I understand.

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[smokinjeep]

Hello,
We regret to hear that your dealers have not been able to assist further with this. Please know that it is a Mopar Vehicle Protection service contract that will provide the calibration needed - called Mopar Custom Calibration. It is recommended that this contact be added to your vehicles if you add 33"+ tires, have a modified axle ratio or transfer case ratio. I have specific steps I can provide your dealers if they are unable to figure this out. However, mentioning that it is a Mopar Vehicle Protection service contract may help. Please send a PM if you need additional assistance.
Julie
Jeep Social Care Specialist

@JeepCares Could you please PM me the specific steps. My dealership cannot figure it out. Thanks.

 

[Fred]

@JeepCares Could you please PM me the specific steps. My dealership cannot figure it out. Thanks.

Just show them this video. I tried three dealers and finally showed the last one this and they did it. I was out in 1/2 hour.

 

[Halstem1]

+1 -- I've been searching for a couple days. It looks like the only way is via a programmer like FlashCal. I just really hate the idea of pulling plugs out of my system to install the bypass for the programmer. Plus $250 - $350 to be able to change tire size and tpms threshold is pretty steep. I know some are gonna say that the programmers have other features. But honestly I don't need a "light show" when I'm out in the woods. Very bitter about this. Don't trust the dealership and don't want a $250+ device that could potentially brick my Jeep's computer.

Yes. This. I’m personally just not a fan of tuners that “hack” the on vehicle software, although i’m sure they work well. I’ve just had bad luck and want to avoid. The dealer re-programmed for the new tire size before I picked up. But the TPMS.... So they can’t change the target pressure? That seems crazy. I’ve had my JL for a few weeks. I could air down to 30# without any warning lights. Actual air pressure was off from computer slightly and not sure why.... gages would read 30 but on board would read 31. I took for first oil change this week. They aired the tires back up to 37. Now when I air down, the light comes on at 32-33 pounds per tire, but only in the back tires. No warning in front tires. I’m so confused.

 

[Fred]

Yes. This. I’m personally just not a fan of tuners that “hack” the on vehicle software, although i’m sure they work well. I’ve just had bad luck and want to avoid. The dealer re-programmed for the new tire size before I picked up. But the TPMS.... So they can’t change the target pressure? That seems crazy. I’ve had my JL for a few weeks. I could air down to 30# without any warning lights. Actual air pressure was off from computer slightly and not sure why.... gages would read 30 but on board would read 31. I took for first oil change this week. They aired the tires back up to 37. Now when I air down, the light comes on at 32-33 pounds per tire, but only in the back tires. No warning in front tires. I’m so confused.

Just ignore the light?

 

[cosmokenney]

Just ignore the light?

What if I want to run my Patagonias at 28 psi and retain a working warning light? Like, when I actually get a flat?

 

[Halstem1]

What if I want to run my Patagonias at 28 psi and retain a working warning light? Like, when I actually get a flat?

Yes. This.

 

[Halstem1]

So fun story for anyone that cares.... so went back to the dealer. Told them that TPMS wasn’t going off before oil change and is after, but only on the 2 rear wheels. All 4 wheels were set to 32#, but only the rear 2 were showing as “low” on the dash. Asked the dealer. He told me it’s set from factory. I asked why only the rear 2 show as low. He asked if my Jeep was here and to pull around. He went and got a service tech to “look at it”. He asked what I want them to be. I said I’d like them at 30#. He told me to pull around to the service bay. So he was really vague and aloof about answering questions. Basically just said the TPMS is a “finicky” system. So he aired them up to 37, and then let air out until they were at 30 and pulled the air chuck off. All were set and no alarm on the dash. Sooo.... I don’t know. Do they know something and just won’t he’ll people? Or did he just trick the system?

 

[DVJeeper]

Bringing back an old thread. I just regeared to 4.88 with 37's and my jeep is freaking out, all kinds of warning lights and issues. I've talked to 3 dealers and all say they cannot change gear ratio, they can only change the tires size. Like others I am trying to avoid using an aftermarket programer if possible. One of the dealers told me that they have tried to doe this and the screen were they would change axle ratio is grayed out and requires a Chrysler engineer access code, which they don't have at the dealership. So frustrating.... I emailed the video to another dealer, waiting to hear back.

37" with stock gearing = no problems, speedo will be off but everything works
37" with regear = Jeep goes to shit, traction control, collision avoidance, 4wd warning lights all come on. Lockers don't work, ugh!

I'll see if anybody has some helpful info or the dealership I sent to video to can help, otherwise I'll order a programer in a couple of days.

 

[cosmokenney]

Bringing back an old thread. I just regeared to 4.88 with 37's and my jeep is freaking out, all kinds of warning lights and issues. I've talked to 3 dealers and all say they cannot change gear ratio, they can only change the tires size. Like others I am trying to avoid using an aftermarket programer if possible. One of the dealers told me that they have tried to doe this and the screen were they would change axle ratio is grayed out and requires a Chrysler engineer access code, which they don't have at the dealership. So frustrating.... I emailed the video to another dealer, waiting to hear back.

37" with stock gearing = no problems, speedo will be off but everything works
37" with regear = Jeep goes to shit, traction control, collision avoidance, 4wd warning lights all come on. Lockers don't work, ugh!

I'll see if anybody has some helpful info or the dealership I sent to video to can help, otherwise I'll order a programer in a couple of days.

Man that doesn't sound right. Did some sensor get disconnected during the regear?

 

[DVJeeper]

I don't think so, we checked wiring and everything looks good. Thinking this through, here is where we think the problem is coming from. It looks like the speedo gets it's information from the ABS system, when we regeared we expected our speedo to be pretty close to accurate (37" w/4.88 are pretty close to stock ratios), but we were still reading 7mph slower than our actual speed.

After regeared, the Jeeps computer is getting information from the trasmission that is not matching the ABS and doesn't like it. With just larger tires, the ABS and Transmission were still sending info that matched. At least that is what I think is going on.

 

[cosmokenney]

I don't think so, we checked wiring and everything looks good. Thinking this through, here is where we think the problem is coming from. It looks like the speedo gets it's information from the ABS system, when we regeared we expected our speedo to be pretty close to accurate (37" w/4.88 are pretty close to stock ratios), but we were still reading 7mph slower than our actual speed.

After regeared, the Jeeps computer is getting information from the trasmission that is not matching the ABS and doesn't like it. With just larger tires, the ABS and Transmission were still sending info that matched. At least that is what I think is going on.

FWIW the FlashCal has a setting for gear ratio, and even tranfer case regear (iirc). I'm sure the Tazer does the same.

 

[DVJeeper]

FWIW the FlashCal has a setting for gear ratio, and even tranfer case regear (iirc). I'm sure the Tazer does the same.

Thank you, that looks like the direction I'll be going.

 

[My#8andlast]

That's definitely not right. I did the exact same regear (4.88 Yukon) and tire size but I had no lights, no nothing while I waited on the programmer to show up. Who did your gears? Maybe take it back to them? Unless you did them, then..........

 

[DVJeeper]

That's definitely not right. I did the exact same regear (4.88 Yukon) and tire size but I had no lights, no nothing while I waited on the programmer to show up. Who did your gears? Maybe take it back to them? Unless you did them, then..........

Regeared on Wednesday and everything was okay until we went wheeling on Sunday. Going into 4lo seemed to be what set everything in motion. I'm not sure if this has anything to do with it or not, but we have the Adaptive Cruise Control option, which might have some additional sensors and programing that is getting messed up. ACC is one of the error lights we are getting and is now not working. If i didn't have this option maybe we wouldn't be running into these issue. These electronics are interconnected, one thing out of sinc can mess up all kinds of stuff.

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