J-Scan tire change broke speedometer and threw lots of codes

[eperks]

New here, first of all, thanks everyone in this community for all the help and advice,

I finally decided to use JScan to change my wheel size from 31.25” to 35”’s, which was a simple task. Unfortunately, after this 1 single change I am now getting these trouble codes:

C1078 (tire revolutions range performance)
C100A (left front wheel speed sensor circuit)
B2305 (wiper park switch input stuck high)
U1417 (implausible left wheel distance signal)
U1418
U1412
U1409

And now my CEL is on, my speedometer doesn’t work and my mileage isn’t increasing. I’m pretty desperate for any help or suggestions, I think I’m going to try and reset the ECU, but I have no idea how to fix this. I’m hoping Jscan didn’t fry any of my modules,

Has anyone had any similar issues? Any suggestions?

 

[JeepJeezy]

You need to put the physical size of the tire in Jscan. Not 35. You're probably like 34.25? But you literally have to measure from the ground up and minus a 1/4". That's what I did to get the speedo perfect and no codes.

 

[BLACKJKU]

New here, first of all, thanks everyone in this community for all the help and advice,

I finally decided to use JScan to change my wheel size from 31.25” to 35”’s, which was a simple task. Unfortunately, after this 1 single change I am now getting these trouble codes:

C1078 (tire revolutions range performance)
C100A (left front wheel speed sensor circuit)
B2305 (wiper park switch input stuck high)
U1417 (implausible left wheel distance signal)
U1418
U1412
U1409

And now my CEL is on, my speedometer doesn’t work and my mileage isn’t increasing. I’m pretty desperate for any help or suggestions, I think I’m going to try and reset the ECU, but I have no idea how to fix this. I’m hoping Jscan didn’t fry any of my modules,

Has anyone had any similar issues? Any suggestions?

The first Code is probably due to the incorrect tire size.

The next is probably a wheel speed sensor

 

[Anybodyhome]

When I got my OBD dongle and JScan and went through the same process, I measured each wheel from the ground to the top of the tire on all 4 corners. Added them all and divided by 4 to get the closest average for each of the 4 tires.

 

[eperks]

You need to put the physical size of the tire in Jscan. Not 35. You're probably like 34.25? But you literally have to measure from the ground up and minus a 1/4". That's what I did to get the speedo perfect and no codes.

I tried changing it back to its original size, but my speedometer (both digital and analog) don’t work and it’s not tracking my mileage, or odometer. I’m at a bit of a loss, I might try and reset my ECU this afternoon.

I know the front left wheel speed sensor was going bad, it started throwing ABS/traction control errors periodically and I got weird readings from it. I’m at a loss for the others


Do you think changing it from 35 to 34.25 would fix all of this?

 

[BLACKJKU]

I tried changing it back to its original size, but my speedometer (both digital and analog) don’t work and it’s not tracking my mileage, or odometer. I’m at a bit of a loss, I might try and reset my ECU this afternoon.

I know the front left wheel speed sensor was going bad, it started throwing ABS/traction control errors periodically and I got weird readings from it. I’m at a loss for the others


Do you think changing it from 35 to 34.25 would fix all of this?

People that have 37" tire put bigger size then a 35 so I doubt if that's the issue. Try going back to the original size and see what happens.

 

[Dirty Dog]

Honestly, I doubt that JScan caused this. Correlation is not causation.
I think you've got a bad wheel speed sensor and potentially other issues as well.

 

[eperks]

People that have 37" tire put bigger size then a 35 so I doubt if that's the issue. Try going back to the original size and see what happens.

Just tried switching back to its original 31.25”, as well as it’s measured value of 34.25”, I might buy another OBD (using VEEPEAK) but I’m running out of ideas

 

[eperks]

Honestly, I doubt that JScan caused this. Correlation is not causation.
I think you've got a bad wheel speed sensor and potentially other issues as well.

I’m positive Jscan caused this, I used an expensive dedicated OBD2 scanner and my Bluetooth Jscan module (veepeak) and had zero codes, then after changing my tire size my speedometer broke, odometer, mileage, and all these codes.

I’m not sure if my ECU or another module got fried during it

 

[JeepJeezy]

Do your windshield wipers work?

 

[macleanflood]

My Jscan would do this occasionally.

You just have to reset everything to stock...set the tire and axle ratio back to normal. Might take a couple of clears and programs but it will work.

The Jscan Facebook group is an excellent source of support.

Never did get it to set the speedo right... something else is f'd up.

-Mac

 

[MacGuyver]

What module are you using Mac? I use the one that Jscan suggests and I've never had any issue like that. To be fair I have a manual and speedometer setting isn't near as important for me, but Jscan has worked flawlessly over two jeeps with two different engines.

 

[Duster]

I’m positive Jscan caused this, I used an expensive dedicated OBD2 scanner and my Bluetooth Jscan module (veepeak) and had zero codes, then after changing my tire size my speedometer broke, odometer, mileage, and all these codes.

I’m not sure if my ECU or another module got fried during it

As Dirty Dog said, "Correlation is not [necessarily] causation." Neither is certainty necessarily correct. There are an immense number of interacting elements that could be interacting differently now. JScan may have enabled the appearance of developing faults that were lurking. For instance how soon after changing out your tires did you use JScan to correct the wheel change wheel size? It is possible that the process of changing the tires may have triggered the break down of an aging element in the sensor and monitoring systems. If you look up the codes, here for instance: https://www.engine-codes.com, you will see that most of them list a number of physical causes, as well as electronic. The first on your list is the only one that lists only a coding error "implausible value programmed . . ." Being sure about a cause is one of the quickest ways to be frustrated in a repair.

 

[Anybodyhome]

coding error "implausible value programmed . . ."

This implies that a number or entry was made that is not recognized by the app. And, bear in mind, the app only makes it possible for you to see what the ECU is reading. Therefore, the ECU saw something unrecognizable, threw a code and passed it along to the OBD dongle and JScan.

 

[macleanflood]

What module are you using Mac? I use the one that Jscan suggests and I've never had any issue like that. To be fair I have a manual and speedometer setting isn't near as important for me, but Jscan has worked flawlessly over two jeeps with two different engines.

One of the ones recommend by Jscan...I even talked to and stumped the developers.

I got a new phone a month or so ago... been meaning to try again.

-Mac

 

[SteveF]

You need to put the physical size of the tire in Jscan. Not 35. You're probably like 34.25? But you literally have to measure from the ground up and minus a 1/4". That's what I did to get the speedo perfect and no codes.

My 35's actually measured 33.75 inches. I put a level across the top of the tireand when the bubble was centered that's what it measured. I didn't have any codes but my speedometer was off and so were my shift points. I also used jscan to change my gear ratio setting when I re-geared my axles. I had no issues.

 

[MacGuyver]

One of the ones recommend by Jscan...I even talked to and stumped the developers.

I got a new phone a month or so ago... been meaning to try again.

-Mac

Strange. I suppose the phone could be a thing. I've only ever used android with it, so I can't speak to how apple works, though you didn't say what kind.

The only "issues" I've had is that I sometime leave the dongle plugged in for extended periods. About 25% of the time when I do this I need to remove and replace the dongle in order to connect. Minor annoyance of a computer being a computer.

Hope it works for you.

 

[Duster]

My 35's actually measured 33.75 inches. I put a level across the top of the tireand when the bubble was centered that's what it measured. I didn't have any codes but my speedometer was off and so were my shift points. I also used jscan to change my gear ratio setting when I re-geared my axles. I had no issues.

The important figure is the unloaded diameter of the tire. It might be more accurate to measure your spare if the tires really are 35 inches in diameter. The real measurement that counts in calulating speed is the circumference of the tire rather than the diameter. You'ld be travelling about 3% faster than your speedometer tells you I think. Probably not enough to worry about, except where your mileage is concerned. It would be better than you thought.

 

[SteveF]

Measuring it the way I did now has my speedometer reading exactly the same as the GPS reading on Google Maps. I figure that is spot on

 

[SteveF]

The important figure is the unloaded diameter of the tire. It might be more accurate to measure your spare if the tires really are 35 inches in diameter. The real measurement that counts in calulating speed is the circumference of the tire rather than the diameter. You'ld be travelling about 3% faster than your speedometer tells you I think. Probably not enough to worry about, except where your mileage is concerned. It would be better than you thoug

The important figure is the unloaded diameter of the tire. It might be more accurate to measure your spare if the tires really are 35 inches in diameter. The real measurement that counts in calulating speed is the circumference of the tire rather than the diameter. You'ld be travelling about 3% faster than your speedometer tells you I think. Probably not enough to worry about, except where your mileage is concerned. It would be better than you thought.

I would be willing to bet that the spare tire would be about 35 inches. It's not being compressed by the weight of the vehicle. The previous owner had it set to 35 and the speedo and shift points were out of wack. You need to measure the tires on the ground and not the spare.