Park sense and speedo calibration

[Rockhound7]

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.

I have a ’22 Laramie with the same issue. I got speedo close with alpa but no sensors. Just curious if you’ve found a resolution or heard back from Alpha? Basically the whole reason I bought the software, cable and OBD reader.

 

[moosem]

I have a ’22 Laramie with the same issue. I got speedo close with alpa but no sensors. Just curious if you’ve found a resolution or heard back from Alpha? Basically the whole reason I bought the software, cable and OBD reader.

Yes, I did get it to work with AlfaOBD. I was skipping a step. After adjusting the tire circumference, you have to connect to the abs module and follow the steps of the abs initialization routine.

This video helped me:

Another tip:

I used the tire size calculator in the link below to get my theoretical circumference in mm. I then decreased it by 3% and entered that value. My Speedo is spot on, first try. This should save you some “trial and error”.

Tire Size Calculator

Free calculator to find the dimensions of a tire based on its code. It also helps in choosing alternative tire sizes based on rim size or comparing two tires.

www.calculator.net

Let me know if you have any other questions.

Good luck!

 

[Rockhound7]

Thank you so much for replying promptly. I recall going through these steps but will try again in next day or two. Thanks again! Encouraging to know someone got it to work on a ‘22!

 

[moosem]

Thank you so much for replying promptly. I recall going through these steps but will try again in next day or two. Thanks again! Encouraging to know someone got it to work on a ‘22!

No problem. What size are your tires? Other members on here have said that 2710mm is the limit. Anything over that causes the park sense errors.

 

[skyhawk42]

Thank you so much for replying promptly. I recall going through these steps but will try again in next day or two. Thanks again! Encouraging to know someone got it to work on a ‘22!

Let me know if you get it working. I also have a 2022 with 35x12.50 ko2’s and I am curious what value works. I haven’t tried it yet, but if there is a confirmed value that get the speedo close and keeps the sensors working that would make it much easier

 

[Rockhound7]

No problem. What size are your tires? Other members on here have said that 2710mm is the limit. Anything over that causes the park sense errors.

35x12.5x22 which is 34.5 inches. Good to know about 2710mm. I measured my tire and I believe it came out 2720. My speedo is still off 1 mph but if 2710 is the limit to allow the sensors to work then I guess it’ll have to be good enough until we have a fix or solution. Just curious, did you set yours at 2710.

 

[Rockhound7]

Let me know if you get it working. I also have a 2022 with 35x12.50 ko2’s and I am curious what value works. I haven’t tried it yet, but if there is a confirmed value that get the speedo close and keeps the sensors working that would make it much easier

Going to try it to work on it tomorrow. Will update afterward.

 

[Rockhound7]

UPDATE:
OK guys, I updated today and basically I used one of the preset tire sizes in the menu. There is a 35 x 12.5 x 18 Toyo AT at the very end of the menu. So when I use that setting it brought me down to 2620mm (I believe) from 2720. However, after completing the entire process with ABS etc. I’m still only 1 mph off, which is not any different from 2720 and now my park sensors work. So I’m just going to leave it there for now. I did not try the lower setting of 2710 to see if it worked because it didn’t seem to make that much or any difference between the two settings I just used.

 

[moosem]

UPDATE:
OK guys, I updated today and basically I used one of the preset tire sizes in the menu. There is a 35 x 12.5 x 18 Toyo AT at the very end of the menu. So when I use that setting it brought me down to 2620mm (I believe) from 2720. However, after completing the entire process with ABS etc. I’m still only 1 mph off, which is not any different from 2720 and now my park sensors work. So I’m just going to leave it there for now. I did not try the lower setting of 2710 to see if it worked because it didn’t seem to make that much or any difference between the two settings I just used.

That’s not bad. I could live with that.

 

[Rockhound7]

Kinda what I was thinking but was wondering why 100mm less seemed just at close. I may mess with it more just to see if I can improve it.
another can of worms: have y’all done anymore with alpha? I’ve done the drl drop outs

 

[frisby5]

I have mine set at 2718 and my park sensor light and ESC light is on so im going to have to change it ,hopefully this fixes it.

 

[redtech]

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.

I had this same issue and put the same size tire on my 21 ram recently, 285/55-22. Parking sensor stopped working after using the alfaobd to adjust the tire size, I trieda few time to adjust but none fixed it, almost bought the zautomotive mod that fixes it for $250, you just saved me some money!!