JSCAN tire size change on 23 1500 help!

[mplaramie]

Was at the dealer for a quick OC and TR so figured I'd ask if they could change my tire size to get my speedo dialed in. Of course, they could not do it. So now on to JSCAN. I have the cable and OBD2 BT reader so I'm ready to go.

Does any have the steps that are needed in JSCAN to change the tire size? From some info found, there is an ABS scan that needs to be done as well. Every video I see if for Jeeps. Any help is appreciated.

 

[theblet]

See my post in this thread. Also make sure you have the correct SGW bypass cable and a supported OBD2 adapter. Not all of them work.

Ultimate OBD JScan Thread

We have very extensive AlfaODB thread so I thought maybe it is time to start one for JScan? Seems JScan is slowly getting upgraded in what it can do and I am an Apple world guy so it is my only option right now. I don't mind buying an Android, but if I can use what I already have why not? I...

5thgenrams.com

TIre size change:

Turn ignition to run with engine OFF

Adaptation > Tire & Axel Settings > Tire Size

Try to pick the closest value to the physical measurement of the tire.

Hit GO

Once applied, turn ignition to off. Leave vehicle and close all doors.

Make sure key is far away from vehicle so the modules can completely go to sleep.

Wait 10 minutes.

Done.

(If any issues or errors run ABS - Static Initialization)

Fine tune with a GPS app on your Phone WITHOUT plugging the USB into the truck. If speedometer is off, repeat as necessary.

 

[mplaramie]

See my post in this thread. Also make sure you have the correct SGW bypass cable and a supported OBD2 adapter. Not all of them work.

Ultimate OBD JScan Thread

We have very extensive AlfaODB thread so I thought maybe it is time to start one for JScan? Seems JScan is slowly getting upgraded in what it can do and I am an Apple world guy so it is my only option right now. I don't mind buying an Android, but if I can use what I already have why not? I...

5thgenrams.com

TIre size change:

Turn ignition to run with engine OFF

Adaptation > Tire & Axel Settings > Tire Size

Try to pick the closest value to the physical measurement of the tire.

Hit GO

Once applied, turn ignition to off. Leave vehicle and close all doors.

Make sure key is far away from vehicle so the modules can completely go to sleep.

Wait 10 minutes.

Done.

(If any issues or errors run ABS - Static Initialization)

Fine tune with a GPS app on your Phone WITHOUT plugging the USB into the truck. If speedometer is off, repeat as necessary.

Thank you. I had seen the post in the past but couldn't find it. Much appreciated.

 

[theblet]

Thank you. I had seen the post in the past but couldn't find it. Much appreciated.

No worries. These are the exact steps I used. Good luck.

 

[jimothy]

Another thing to watch out for: make sure you are on level ground when you run the ABS calibration.

I did mine in my sloped driveway, which turned out to be a mistake. The most obvious impact was that pitch was incorrect in the off-road pages by several degrees. But had I not taken the truck out on a short camping trip, I wouldn’t have even noticed that.

The second thing I noticed was that the engine wouldn’t shut off at some stop lights in my eTorque. When I checked the stop/start status, it said the slope was too steep.

Even if you don’t have the off-road group or eTorque, there might be other, less obvious things thrown off. Once I figured out that the calibration was connected to what I observed, the fix obvious: recalibrate on flat ground. But it took me over a week to make that connection.

 

[mplaramie]

Another thing to watch out for: make sure you are on level ground when you run the ABS calibration.

I did mine in my sloped driveway, which turned out to be a mistake. The most obvious impact was that pitch was incorrect in the off-road pages by several degrees. But had I not taken the truck out on a short camping trip, I wouldn’t have even noticed that.

The second thing I noticed was that the engine wouldn’t shut off at some stop lights in my eTorque. When I checked the stop/start status, it said the slope was too steep.

Even if you don’t have the off-road group or eTorque, there might be other, less obvious things thrown off. Once I figured out that the calibration was connected to what I observed, the fix obvious: recalibrate on flat ground. But it took me over a week to make that connection.

Great info. I have a sloped driveway and was going to do it there. Now I'll hit a level parking lot and do a chalk test on the tires. Might as well do the tire size change and TPMS in one shot......

 

[theblet]

Great info. I have a sloped driveway and was going to do it there. Now I'll hit a level parking lot and do a chalk test on the tires. Might as well do the tire size change and TPMS in one shot......

Rock and roll! I put my TPMS to 30psi.

 

[Sigfla]

Theblet, this part I don’t understand “Fine tune with a GPS app on your Phone WITHOUT plugging the USB into the truck. If speedometer is off, repeat as necessary.” Do you mean not plugging the phone into the truck?

 

[jimothy]

Theblet, this part I don’t understand “Fine tune with a GPS app on your Phone WITHOUT plugging the USB into the truck. If speedometer is off, repeat as necessary.” Do you mean not plugging the phone into the truck?

Keeping the phone unplugged is so it doesn’t use the truck’s GPS instead of its own. I’m not sure that matters, unless the speedometer app on your phone would also use your truck’s speedometer.

That would defeat the purpose; you want to measure speed using GPS so you can check the accuracy of the truck’s speedometer.

 

[Sigfla]

Keeping the phone unplugged is so it doesn’t use the truck’s GPS instead of its own. I’m not sure that matters, unless the speedometer app on your phone would also use your truck’s speedometer.

That would defeat the purpose; you want to measure speed using GPS so you can check the accuracy of the truck’s speedometer.

The app I use doesn’t use the truck gps. I was confused the OP meant either the phone or the OBD reader. I am still trying to figure it out and want to make sure once tire size is entered that I don’t have to keep the obd module plugged in.

 

[theblet]

Theblet, this part I don’t understand “Fine tune with a GPS app on your Phone WITHOUT plugging the USB into the truck. If speedometer is off, repeat as necessary.” Do you mean not plugging the phone into the truck?

Yes don’t plug it in to the truck. You want to make sure your phone uses its own gps and not the trucks gps. My phone was matching pretty well until about 60 mph. So I had to adjust the tire size just a bit from the measurement I took. Here’s the gps apps I used

 

[Sigfla]

Ok I think I am 99.9% of the way there. This is gonna sound dumb but just so I am totally clear once the change is made and you turn the truck off you plug the OEM wires back into the SGW and walk away correct? Wait 10 mins and you should be good to go?

 

[theblet]

Ok I think I am 99.9% of the way there. This is gonna sound dumb but just so I am totally clear once the change is made and you turn the truck off you plug the OEM wires back into the SGW and walk away correct? Wait 10 mins and you should be good to go?

I haven’t plugged the oem wires back in at all. The sgw bypass is still in place on my truck. Doesn’t hurt anything. If I have to bring it to the dealer for any reason, I’ll put it back to factory.

So just leave everything as is, turn the truck off, and walk away with the key fob so the whole truck can go to sleep.

Then you’re good to go.

You can put the wires back once you have it dialed In if you like.

 

[SigRam]

Worked like a charm. Latest UConnect version. 2023 with digital dash. Used the Veepak reader and cable adapter off amazon. All done on level ground. Made 2 changes going up in size till speedo was correct. Did my 5 minute sleep cycles in between and did 1 last sleep cycle when I got home before I unplugged the cable and put the wires back to the OEM plugs in the SGW. No errors and no issues. Very simple. Jscan developer was johnny on the spot with any questions I had and responded via FB messenger immediately. Demo mode is great to test the waters before you do anything.

 

[theblet]

Worked like a charm. Latest UConnect version. 2023 with digital dash. Used the Veepak reader and cable adapter off amazon. All done on level ground. Made 2 changes going up in size till speedo was correct. Did my 5 minute sleep cycles in between and did 1 last sleep cycle when I got home before I unplugged the cable and put the wires back to the OEM plugs in the SGW. No errors and no issues. Very simple. Jscan developer was johnny on the spot with any questions I had and responded via FB messenger immediately. Demo mode is great to test the waters before you do anything.

Great work!