Park sense and speedo calibration

[Doofus74]

Any tuner work for speedometer calibration for 35x12.50 and park sense? I had factory lift with hyper tech tuner and park sense won’t come on. They will be fixing that. Not dropping 60 grand on new truck and things don’t work.
Any ideas?

 

[dts828]

Check with tazer, they had limitations on size with park sense working I think on the 21's but was working on fixing problem. IIRC they can correct up to 35's. Perhaps others can chime in with additional info.

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[Doofus74]

Check with tazer, they had limitations on size with park sense working I think on the 21's but was working on fixing problem. IIRC they can correct up to 35's. Perhaps others can chime in with additional info.

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I hope so. I have a 2021

 

[dts828]

I hope so. I have a 2021

Doesn't say much but below thread says it works up to 35.

What speedo calibrator for 2020 with park assist?

I had a rough country one but it won’t work with the park assist I have a 6” lift and 35’s. My oem had the 22s so my speedo is off by a few kmh I would like for it to be right what calibrator tools work? I just read about the auto calibration feature which seems like a bust. Does the tazer...

5thgenrams.com

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[Techna]

My Hypertech speedometer calibrator and ParkSense seem to play nice together. I’m adjusted for 35” tires and it took some experimenting to get it dialed as far as getting the speed correction right. I don’t remember ParkSense protesting any of the sizes I tried in the calibrator during the process.

 

[Mark985]

I have the rough country speedometer calibrator and never had any issues with anything. I believe rough country just rebrands the hypertech one.

 

[Ram Dude]

Ditto...What Mark985 said

 

[Doofus74]

So I took truck into tire place for retorque on suspension kit and alignment. They said it because it has electronic steering and has a sensor. So truck has a slight to the right when aligned. Will need a re flash on computer and it should work. We shall see on Tuesday

 

[Doofus74]

So went to tire dealer agin today. They “updated” the tuner, went back to stock and then reinstalled the tire correction. Same thing no parking sense available comes up a d they turn off. Took it to the dealer and the found a code, cleared it and reprogram the park sense. Low and behold no more issues, they tried sending me on my way, I asked if they updated the truck with the tuner for the 35 tires as the Chrysler tuning won’t go that high. They gave me the run around saying it’s the tire dealer. I then lost my **** in them made them use the hyper tech tuner, and wouldn’t you know it park sense it broke again. So I got a loaner for the night as tired of eating gas and miles in the truck not to mention all damn evening. Needless to say they better fix it or they can swap trucks!!
Don’t think the tunes work in 2021 so be cautious if you plan on it. More to follow as it gets sorted one way or the other.

 

[MayhemMOORE]

I used AlfaOBD to do my calibration and found that while calibrating for the 285/55R22 (roughly 34.4") tires I put on, anything over 2710mm circumference caused parksense to freak out. The math works out to about 2740mm circumference for that tire size, but over multiple attempts to get the speed dialed in, I believe I ended up at 2670mm which put it dead on with gps at any speeds I drive and plays nice with parksense.

Try measuring the actual height of the tire as it sits on the truck using a level across the tread, then use that to figure up what size to actually calibrate for. This is what I ended up doing and it put me within a few mm of my end result which is within the limits of what allows parksense to work properly.

 

[Doofus74]

So ditched the truck and just gave it back to them and got a 2021 limited with normal size tires. But for others who have issues here is what I found.
Ram updated the software this year and it messes with aftermarket tuners. It was tuned with the Hyper tech, but as mentioned broke the parking sense. They found out the dealer had to pay corporate Ram $100 to unlock the ability to adjust tire size with their own flash instead of the Hyper tech. They told me this is basically all a cash grab by corporate. So that is what I was told.
I decided not worth the hassle of having future issues and maybe running into that issue again with any repairs or computer updates. That pissed me off and I then looked into other possible issues. The dealer also has free lifetime limited warranty on power train. They was invalid with lifted trucks and not applicable. So I just moved into the 2021 limited with e torque and off road package. Forget all the tires and lift.
Hope that helps others if they have issues?

 

[Doofus74]

Anyone else have updates? I got a new 2021 ram 3500 that has 37x12.50x20. I know the Speedo is off and the sensors work now. I’m afraid to mess with it being a long bed 6 inch lift, as I use the sensors as a CYA!!!

 

[mays9185]

You got to pay ram so tech can unlock it and can only go to 33.5 tire.other wise park sense will be dead in the water.

 

[moosem]

Sorry to rehash this old post. Does anyone have any updated info on this issue? Will AlfaOBD, or any other calibration tool, allow speedo cal without disabling Parksense? Thanks in advance!

 

[NoOtherHobby]

Sorry to rehash this old post. Does anyone have any updated info on this issue? Will AlfaOBD, or any other calibration tool, allow speedo cal without disabling Parksense? Thanks in advance!

For what it's worth, I installed the Tazer DT when I did a 6" lift on my 2020 Rebel. I added 37x12.5 tires. Calibrated for about 36.8 and I get accurate speedometer reading and my parking sensors all still work.

 

[moosem]

For what it's worth, I installed the Tazer DT when I did a 6" lift on my 2020 Rebel. I added 37x12.5 tires. Calibrated for about 36.8 and I get accurate speedometer reading and my parking sensors all still work.

That’s the device that you have to install under the hood, correct?

 

[PurpleRT]

No Tazar is a ODBII install. You’re probably thinking Pulsar.


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[moosem]

No Tazar is a ODBII install. You’re probably thinking Pulsar.


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Yes, I am. Thank you!

 

[moosem]

I was at the dealership today so I walked over to the service area and asked them if they provide speedometer calibration service.

They told me that they do not recommend changing the tire size on these trucks because it messes up all the sensors, and that if I ever needed my windshield replaced, I would have to return to the stock tire size otherwise it cannot be calibrated?

Does this make sense to anybody? Has anyone ever heard of this?

I bought everything I need to do it myself, and plan on using AlfaOBD, but I just figured I would ask them since I was there anyway.

Can someone please tell me that I have nothing to worry about? Lol.

 

[moosem]

I can confirm that AlfaOBD did not work on my 22 Laramie.

Even if I increased the circumference by only 1mm it disabled Park Sense and forward collision warning.

I emailed AlfaOBD and they said they are aware of the issue but they do not have a solution yet.

I guess I’ll have to live with a slightly off speedo for now.