Troubleshoot Wheel Speed Sensors with JScan

[JerryD]

I see a lot of threads asking for help troubleshooting symptoms, which is good. We can all learn from each other. A recent thread had someone using a code reader that actually indicated the problem was a speed sensor and which one it was. Nice! However, at $90, it still cost more than a $25 scanner and the app at $24. Now, there is a lot to be said for having a dedicated scan tool... portability, convenience, etc. but for those that have this particular app and are wondering how exactly to use it, I took some screen shots of HOW to show the wheels speed sensors when you get the the common symptoms: ABS Light/Traction Control Light on. There may be other symptoms, too. Can't recall... Its been a while since my last speed sensor went out, but here is the quick check you can do with the jScan app.

Start the app...

Select "Modules"

Select "Anti Lock Brakes"

Then "Live Data"

Click the orange circle with "..." to search for the appropriate PIDs. Type "wheel speed" in the search bar and select the LF (left front), LR (left rear), RF (right front), & RR (right rear) Wheel Speed sensors (mph) as shown below.

And you'll get this...

If this was a live shot (sorry, not that ambitious), it would show values as your are driving. A bad sensor would be zero as the others would have a value.

I wrote this to show what can be done with apps like these. I also use AppCar FCADiag, Torque and OBDLink, the latter really just for monitoring. Anyway, whatever product you use, learn HOW to use it. And when you are successful, post up the steps so that others can learn.

Chris, if this is too long or irrelevant, it won't hurt my feelings if you delete. I just want to encourage people to learn the tools that are available.

 

[mrjp]

Thats very Good Info

 

[BLACKJKU]

I see a lot of threads asking for help troubleshooting symptoms, which is good. We can all learn from each other. A recent thread had someone using a code reader that actually indicated the problem was a speed sensor and which one it was. Nice! However, at $90, it still cost more than a $25 scanner and the app at $24. Now, there is a lot to be said for having a dedicated scan tool... portability, convenience, etc. but for those that have this particular app and are wondering how exactly to use it, I took some screen shots of HOW to show the wheels speed sensors when you get the the common symptoms: ABS Light/Traction Control Light on. There may be other symptoms, too. Can't recall... Its been a while since my last speed sensor went out, but here is the quick check you can do with the jScan app.

Start the app...

View attachment 118915

Select "Modules"

View attachment 118918

Select "Anti Lock Brakes"

View attachment 118919

Then "Live Data"

View attachment 118920

Click the orange circle with "..." to search for the appropriate PIDs. Type "wheel speed" in the search bar and select the LF (left front), LR (left rear), RF (right front), & RR (right rear) Wheel Speed sensors (mph) as shown below.

View attachment 118917

And you'll get this...

View attachment 118916

If this was a live shot (sorry, not that ambitious), it would show values as your are driving. A bad sensor would be zero as the others would have a value.

I wrote this to show what can be done with apps like these. I also use AppCar FCADiag, Torque and OBDLink, the latter really just for monitoring. Anyway, whatever product you use, learn HOW to use it. And when you are successful, post up the steps so that others can learn.

Chris, if this is too long or irrelevant, it won't hurt my feelings if you delete. I just want to encourage people to learn the tools that are available.

You can do all of this but you can't Google, i'm amazed. I don't have a JScan because it looks to complicated.

 

[IndominusHuman]

It's weird that you posted this last night. I actually used this function yesterday. I had a wheel speed sensor fail on me and I needed to find out which one it was (i had an error code for the left front, but wanted to double check). So i got into this module and looked for which one was not reading. Way cheaper than having to find a scanner that does ABS stuff.

 

[Daddyo2373]

Nice write up!

 

[Danarch]

It's weird that you posted this last night. I actually used this function yesterday. I had a wheel speed sensor fail on me and I needed to find out which one it was (i had an error code for the left front, but wanted to double check). So i got into this module and looked for which one was not reading. Way cheaper than having to find a scanner that does ABS stuff.

So did you assume it was a wheel sensor because the two lights were on or was there something else? Dumb question I suppose you follow JerryD instrutions then go for a drive to monitor the speed, how else would know the speed? I ask as the 2015 Sahara we bought the ABS and ESC lights keep coming on and going off. They may stay on 30 or 60 seconds then off. We can go a day with nothing then they come on 2 or 3 times in 20 minutes. They were on last night and I grabbed my scanner whenever pulled into the drive and they went out. There weren’t any codes in the system. I purchased a second Jscan license last night and plan on doing the above and see what happens. I’ll just swap out the bluetooth OBD reader.

If any help it is 2015, Sahara, 88,00 miles, automatic. It does have 275/70R18 tires. Not sure if the system has been programmed for the larger tires, but wouldn’t think that would cause the ABS / ESC lights to come on. I tracked it the Gaia GPS app and it showed us moving about 1 mile faster then the electronic speedomete.

 

[BLACKJKU]

So did you assume it was a wheel sensor because the two lights were on or was there something else? Dumb question I suppose you follow JerryD instrutions then go for a drive to monitor the speed, how else would know the speed? I ask as the 2015 Sahara we bought the ABS and ESC lights keep coming on and going off. They may stay on 30 or 60 seconds then off. We can go a day with nothing then they come on 2 or 3 times in 20 minutes. They were on last night and I grabbed my scanner whenever pulled into the drive and they went out. There weren’t any codes in the system. I purchased a second Jscan license last night and plan on doing the above and see what happens. I’ll just swap out the bluetooth OBD reader.

If any help it is 2015, Sahara, 88,00 miles, automatic. It does have 275/70R18 tires. Not sure if the system has been programmed for the larger tires, but wouldn’t think that would cause the ABS / ESC lights to come on. I tracked it the Gaia GPS app and it showed us moving about 1 mile faster then the electronic speedomete.

Is the steering wheel centered when going down the road?

 

[Danarch]

Yes, the steering wheel is centered. That said there is a very slight pull to the right so will have the alignment looked at in the near future. If you let go of the steering wheel it is very slightly off center and will travel to the right. It has crossed my mind if that is the issue, but it is so minor and with the steering wheel being centered and going straight didn’t think that would be the issue.

 

[BLACKJKU]

Yes, the steering wheel is centered. That said there is a very slight pull to the right so will have the alignment looked at in the near future. If you let go of the steering wheel it is very slightly off center and will travel to the right. It has crossed my mind if that is the issue, but it is so minor and with the steering wheel being centered and going straight didn’t think that would be the issue.

I would almost bet that is the issue.

 

[Danarch]

Thank you for your input BLACKJKU. Went ahead and made an appointment for Friday to rule it out. Either way we were planing on getting it done. When did cars get so finicky ? Also getting transfer case and transmission fluids changed just for the fun it. Who know what the PO did and didn’t do. Dealer changed the oil already. Wanted those two done before I add skids. Will do differentials later.

 

[BLACKJKU]

2007 is when the JK's became electrical nightmares.

Just to let you know those 2 lights on won't be any problem, my JK has a button to push that shuts the ESP off and then those lights come on until you either shut off the Jeep or push the button. No sure what all years had that.

 

[Danarch]

Thank you, I was wondering if they would creat an issue or not. Based on my understanding didn’t seem like they would. It does have the button that you are referring to. I haven’t tried it on hers yet, but on the Rubicon if I hit it a different light shows up on the dash (same symbol) and says “off” underneath it. We did hit the button on hers after the other two lights came on and nothing happened, but by then maybe it doesn’t function.

One thing I forgot to mention is sometimes the “hill decent” light will flash when the ABS ESC light first comes on then turns off.

 

[BLACKJKU]

My Jk doesn't have hill decent as far as I know. It's even out there how to disable the ESP if you don't have the button.

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[MacGuyver]

My Jk doesn't have hill decent as far as I know. It's even out there how to disable the ESP if you don't have the button.

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To my understanding, hill decent is a function of auto trans, and us with the manual ones don't get it because we just downshift.

 

[Danarch]

Okay, first Jerry your instructions worked great. So I hooked up the Jscan app backed out of the drive put it drive and thought I saw one of rear sensors flash, then the lights went out. Drove all around trying to get them to come back on or see if the app showed anything, nothing but wheel speed. When I got home for the fun of it selected “get codes” and there it was, right rear wheel sensor showed two errors. One said erratic sensor stored in ABS. Can’t remember the other one, but both rr. I didn’t realize if I unplugged the obd reader the Jscan app would just exit everything out. Lesson learned, take screen shot next time. Well try and get oem replacement, didn’t see it on rockauto.

I did find them. Thought it odd some aftermarket ones listed specific wheel locations. Went ahead and ordered 2, figured between 8 wheels will need another one and will be good to have in hand.

Thanks guys. Still have alignment scheduled for Friday.

 

[Danarch]

To my understanding, hill decent is a function of auto trans, and us with the manual ones don't get it because we just downshift.

Yup, i don’t have that feature in the Rubi. I was wondering why hers had it, just figured cause it’s a Sahara. I swear her Sahara is quieter and smoother then the Rubi. Maybe cause of it being an automatic.

 

[SteveF]

Great info here, thanks everyone!

 

[IndominusHuman]

So did you assume it was a wheel sensor because the two lights were on or was there something else? Dumb question I suppose you follow JerryD instrutions then go for a drive to monitor the speed, how else would know the speed? I ask as the 2015 Sahara we bought the ABS and ESC lights keep coming on and going off. They may stay on 30 or 60 seconds then off. We can go a day with nothing then they come on 2 or 3 times in 20 minutes. They were on last night and I grabbed my scanner whenever pulled into the drive and they went out. There weren’t any codes in the system. I purchased a second Jscan license last night and plan on doing the above and see what happens. I’ll just swap out the bluetooth OBD reader.

If any help it is 2015, Sahara, 88,00 miles, automatic. It does have 275/70R18 tires. Not sure if the system has been programmed for the larger tires, but wouldn’t think that would cause the ABS / ESC lights to come on. I tracked it the Gaia GPS app and it showed us moving about 1 mile faster then the electronic speedomete.

Sorry for just getting back to this. Full time work plus full time grad school takes up most of my time

I knew it was a wheel speed sensor simply because when mine when out I was on a cross country road trip. Heading down the interstate at 3 in the morning and suddenly all of the typical lights came on and I lost cruise control. Mine didn't have a slow death. Once it died...it died.

It looks like your sensor finally registered as bad in Jscan too.

For others who may see this thread later on, if you do not see the codes, but suspect its a wheel speed sensor, you can go into the Jscan app and monitor the wheel speed individually. This can tell you if one is actually bad or not even if no codes are appearing.

 

[IndominusHuman]

Yup, i don’t have that feature in the Rubi. I was wondering why hers had it, just figured cause it’s a Sahara. I swear her Sahara is quieter and smoother then the Rubi. Maybe cause of it being an automatic.

Another factor to softness and loudness is the extras on a Rubi. The extra bits add weight and can catch wind unlike others.

 

[Anybodyhome]

Also keep in mind these sensors, because of their physical location in relation to the wheels, can get mucked up if you go off-road or just from the build up of road grime and dirt.