Alpha OBD tire size help

[jonnyrebel88]

So I have a 2019 Rebel and was using Alpha OBD software via my laptop with windows software, an ECRI security bypass, and an OBDLink EX adapter. Today I tried to adjust my tire size to 295/70r18 which comes out to 2733mm in the input of changing the tire size. I entered all the information as per another thread on here in the Change tire size, car configure tire size, and then also did the ABS configuration as well. Now I have an issue with the parking sensors not working front or rear. I have tried to redo it 3 times going as low as 2644mm which is supposed to be the stock size, but still no luck. Any help would be greatly appreciated.

 

[thewalrus88]

They have nothing to do with each other, not even the same module. Are the switches on?

 

[jonnyrebel88]

They have nothing to do with each other, not even the same module. Are the switches on?

The switches are lit up and if you hit either of them it says unavailable

 

[vincentw56]

The switches are lit up and if you hit either of them it says unavailable

This is common issue with changing tire size. I don't know how to fix it, but maybe someone else does. @Jimmy07

 

[socalnonsage]

Glad it's not just me - same thing happened with my 2020 Ram Bighorn. Both front and rear parking/proximity sensor packs stopped functioning after updating tire size in AlphaOBD.

Lights on the switches are illuminated but when pressed, "unavailable" message is shown on the instrument cluster, the lights on the switches flash several times but they never switch on.

I'm scheduled for a dealership visit this Friday to diagnose a (voltage fault/error) issue with a low-beam headlight wiring harness so when it's in, I'll tell them about the sensors as well.

 

[Daverous]

Did you make a settings log prior to changing things, or have one from recently? If so use winmerge to check for variations.
I ran into a similar setup and lost multiple items. I was able to determine some odd changes alfaobd made and revert them to get my parking, stability, and some other items back in actionafter tire calibration. Also run an error scan to get some additional insight for us/you and report back with the codes thrown by bcm, abs, and pcm while you're at it. That may also assist in tracking the fault down.

Here are the issues I encountered, as well as what I reverted to to fix my issues. Not saying yours is the same, but you get the idea.

Tire size change (alfaobd) now bunch of codes/lights wont go away

I have a 2021 1500 Laramie with adaptive cruise, air suspension, etc. I went to change tire size and followed the AlfaOBD process of setting the circumference in 2 locations of the BCM and then going through the ABS initialization process. I try to reset the codes, but when I turn the key off...

5thgenrams.com

 

[Lpsouth1978]

When I did mine, I simply kept reducing it until it no longer caused the issue, then went back up 1mm at a time until it did it again, then I backed off 1mm and all is good. Luckily, The final number is perfect for my speedo, though significantly lower than the actual measurement. At least in my case, the number I ended up with in AlfaOBD did not match the real tire size, though this may not be the case for everyone.

 

[jonnyrebel88]

Did you make a settings log prior to changing things, or have one from recently? If so use winmerge to check for variations.
I ran into a similar setup and lost multiple items. I was able to determine some odd changes alfaobd made and revert them to get my parking, stability, and some other items back in actionafter tire calibration. Also run an error scan to get some additional insight for us/you and report back with the codes thrown by bcm, abs, and pcm while you're at it. That may also assist in tracking the fault down.

Here are the issues I encountered, as well as what I reverted to to fix my issues. Not saying yours is the same, but you get the idea.

Tire size change (alfaobd) now bunch of codes/lights wont go away

I have a 2021 1500 Laramie with adaptive cruise, air suspension, etc. I went to change tire size and followed the AlfaOBD process of setting the circumference in 2 locations of the BCM and then going through the ABS initialization process. I try to reset the codes, but when I turn the key off...

5thgenrams.com

I unfortunately did not make a settings log prior to changing it. I will take a look at your issues and see if mine is the same way. There are no codes stored in anything so I'm not sure if it reverted to turning the sensors off or something like that when reconfiguring the settings.

 

[jonnyrebel88]

One update on the truck, driving it the past few days I have noticed on startup the sensors will work for a few seconds. I'm wondering if changing the tires size somehow disables the park assist module and just needs be reset through the car configuration. I will get back on Alpha OBD tomorrow and check it out

 

[MoreOvalteenPlz]

I followed these instructions when I recalibrated for my 275/65R20’s (2672 mm) and have never had any issues with the parking sensors not working. I use the ERCI security gateway bypass and OBDLink MX+.

 

[HSKR R/T]

I followed these instructions when I recalibrated for my 275/65R20’s (2672 mm) and have never had any issues with the parking sensors not working. I use the ERCI security gateway bypass and OBDLink MX+.

Those are 34's, but actually need to be set at about 33.5 for proper speedo calibration. Sensors only freak out at 35+ inch tires

 

[jonnyrebel88]

I followed these instructions when I recalibrated for my 275/65R20’s (2672 mm) and have never had any issues with the parking sensors not working. I use the ERCI security gateway bypass and OBDLink MX+.

Those are actually the same exact directions I used! lol I used the ECRI and the same obdlink as well. For some reason still setting the sensors off

 

[Laramie 2021]

Those are actually the same exact directions I used! lol I used the ECRI and the same obdlink as well. For some reason still setting the sensors off

On my '21 Laramie the front and rear sensors were doing the same thing.
I started from scratch for a third time and they work again.

I started the process with the ignition in the Run setting....
Dropped my tire size to 2695 from 2715 (LT 285/65/r20)
Next thing I did was get into the Car Configuration Change and set the tire size to 2695 where it says Dynamic tire circumference.
Exit out of Alpha, shut truck off, unplugged the Bluetooth reader and left the truck off for 15 minutes.

Never did go to the ABS screen ...never had a CEL and the ABS works great!

Great info on this site!
Hope to learn and participate even more.

.

 

[Namerifsaxet1]

Finally tried updating tire circumference and 4wd, abs, rain sense lit up. 2707mm

I’ll give it a rest and see what happens…