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Discussion Starter · #1 ·
So I got a Left Rear ABS Sensor error, which causes all sorts of things to not work on the 500e, no Regen, no Hill Hold, no ESC, and of course, no ABS. Other than that the car drives exactly the same. So I went and bought a new ABS sensor, and installed it on the left rear. And I still have the error. I used AlfaOBD to show the sensor at work, and it definitely shows an error. So my question is, would the left and right possibly be reversed, like the brake light message?
108890
 

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So I got a Left Rear ABS Sensor error, which causes all sorts of things to not work on the 500e, no Regen, no Hill Hold, no ESC, and of course, no ABS. Other than that the car drives exactly the same. So I went and bought a new ABS sensor, and installed it on the left rear. And I still have the error. I used AlfaOBD to show the sensor at work, and it definitely shows an error. So my question is, would the left and right possibly be reversed, like the brake light message?
View attachment 108890
That would be perfectly believable.

Another thing, somewhat related is the temperature: try monitoring pretty much any temp in AlfaOBD and you will see values in F, although the description and the full battery report is in C. This is Italian, remember? The other left.
 

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Did you use AlfaOBD to clear the error code? If so, & it still didn't work*:

Alels may make fun of me again like he did on a recent 12V failure thread, but some users have reported error codes clearing themselves after a few days/drives, & others have said that was due to the key cycling off 5 times, each time long enough for the screen to go fully black (not just dark grey), which takes 1.25 minutes on my 2013. Easy/quick to try anyway.

*I tried to clear an error code on a gas car with the "Torque" app & the same Bluetooth dongle I use with AlfaOBD, & it wouldn't clear.
 

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Discussion Starter · #6 ·
No, it's not an intermittent error, I've been driving with it like that for weeks. Which is why I finally ordered a replacement sensor. After I installed it, and cleared the errors, it worked fine, for about 1000 feet, then threw the errors again. Maybe it's a bad connection farther down the wire.
 

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Discussion Starter · #7 ·
I disconnected the right side sensor, and that verified the left side sensor is the bad one. So I guess I have to check the connector on the ABS block, since it appears that's where the sensor is plugged into.
 

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I had the same problem in my 2008 Jeep Wrangler. Took it to the community college where I work. The automotive tech guys said is was the wheel speed sensor. I drove around the parking lot while the automotive tech guy sat in the passenger seat using the wiTech software and showed the pulses going, then stopping, then going again. It was an intermittent failure. Replaced the wheel speed sensor. Problem did not go away. It turned out the problem was actually in the wiring harness up to the wheel speed sensor. The wire harness flexes with the vehicle suspension. Over time the wires in the flexing harness break.
 

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2017 Fiat 500e (Billet Argento), 2015 VW Golf Sportwagen TSI 5MT (Tungsten Silver), 2002 Honda VFR
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I dont know if your car is lowered or modified but its possible the ABS wire was yanked to far when changing springs?
 

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So I got a Left Rear ABS Sensor error, which causes all sorts of things to not work on the 500e, no Regen, no Hill Hold, no ESC, and of course, no ABS. Other than that the car drives exactly the same. So I went and bought a new ABS sensor, and installed it on the left rear. And I still have the error. I used AlfaOBD to show the sensor at work, and it definitely shows an error. So my question is, would the left and right possibly be reversed, like the brake light message?
View attachment 108890
Would anyone know if it's possible to get this AlfaOBD screen with the demo version? Or does it require the full $49 version?

I have the dreaded ABS/RBS/ESC light trio. Tried the 12V disconnect. Disconnected the humidity sensor. Done more than 10 3 minute key offs. So now I am looking for real error codes and realtime wheel sensor data like the screen above.

It looks like the wheel sensors only run about $25 or so. I'd be willing to invest the $49 to get the screen above, see what the codes are, and have the ability to do a reset.

ga2500ev
 

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Absolutely awesome information! Thank you!

After getting connected, it took all of 5 seconds after pulling off to see that the right rear wheel sensor wasn't registering.

Since other than the bluetooth CanBus unit this is so easy and free for the software, it should be the first diagnostic to do before trying anything else.

Off to get the wheel sensor to hopefully fix the problem.

ga2500ev
 

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I'm pretty sure someone said the signal can be reversed left-right, so you might want to double check by unplugging one & retesting.

Personally I'd say the very first thing to do was unplug the humidity sensor, since it not only causes false alarms, but also reduces range by powering up the A/C compressor & preventing efficient recirculate mode. Plus it's FREE-free 🙂 (don't even need $17 obd dongle).
 

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I'm pretty sure someone said the signal can be reversed left-right, so you might want to double check by unplugging one & retesting.

Personally I'd say the very first thing to do was unplug the humidity sensor, since it not only causes false alarms, but also reduces range by powering up the A/C compressor & preventing efficient recirculate mode. Plus it's FREE-free 🙂 (don't even need $17 obd dongle).
You do know that I wrote my description for you, right? I think you missed it:

Tried the 12V disconnect. Disconnected the humidity sensor. Done more than 10 3 minute key offs.
I pay very close attention to your suggestions because they are so helpful.

ga2500ev
 

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Thanks. I did read what you wrote, so I'll try again:

Temporary 12V disconnect didn't work for YOU, permanent humidity sensor disconnect didn't work for YOU, OBD says it's YOUR right rear speed sensor (might actually be the left).

For someone ELSE, the first thing is to disconnect the humidity sensor, unless it has already been properly unplugged.
 

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Thanks. I did read what you wrote, so I'll try again:

Temporary 12V disconnect didn't work for YOU, permanent humidity sensor disconnect didn't work for YOU, OBD says it's YOUR right rear speed sensor (might actually be the left).

For someone ELSE, the first thing is to disconnect the humidity sensor, unless it has already been properly unplugged.
At this point I'm starting to think that the decision point may be whether or not you already have a BT dongle or not. I agree to disconnect the humidity sensor regardless as it's an energy sucking, code throwing culprit. But if one already has the dongle, it takes longer to download AlfaOBD and set up the connection than it takes to get the real time data to get a definitive diagnosis.

Now on to the fix, which is running into a problem. Apparently the superceded wheel sensor is the only one Chrysler/FIAT is carrying. There is a post elsewhere that model: 68174026AD doesn't work on 2015 and older 500e and that only the original 68174026AC part functions properly. But the latter seems to be made of unobtainium. I would appreciate if anyone chimed in on the difference if they replaced their wheel sensor in a pre-2016 model.

ga2500ev
 

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Now on to the fix, which is running into a problem. Apparently the superceded wheel sensor is the only one Chrysler/FIAT is carrying. There is a post elsewhere that model: 68174026AD doesn't work on 2015 and older 500e and that only the original 68174026AC part functions properly. But the latter seems to be made of unobtainium. I would appreciate if anyone chimed in on the difference if they replaced their wheel sensor in a pre-2016 model.
Can you link that post? as far as a supercession not working, I doubt it. Wheel speed sensors are hall effect sensors, really the only thing that will keep them from working is the strength of the magnet which they are sensing, or the gap to said magnet.

Considering the magnets are part of the wheel bearing/hub (front/rear) It's possible an aftermarket hub, or bad bearing is causing the issue. It's also possible that the gap has changed, and is out of spec (if the sensor was removed, and when reinstalled wasn't seated correctly, or had debris under the sensor, etc)
 

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Can you link that post? as far as a supercession not working, I doubt it. Wheel speed sensors are hall effect sensors, really the only thing that will keep them from working is the strength of the magnet which they are sensing, or the gap to said magnet.

Considering the magnets are part of the wheel bearing/hub (front/rear) It's possible an aftermarket hub, or bad bearing is causing the issue. It's also possible that the gap has changed, and is out of spec (if the sensor was removed, and when reinstalled wasn't seated correctly, or had debris under the sensor, etc)
Here you go: ABS Sensor fix for 2015 Fiat 500e. Post #10.

I'm having a bit of a chuckle as post #9 over there refers to a thread over here.

ga2500ev
 

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Here you go: ABS Sensor fix for 2015 Fiat 500e. Post #10.

I'm having a bit of a chuckle as post #9 over there refers to a thread over here.

ga2500ev
I suspect when the "bad" sensor was removed, and the "good" sensor was installed, it was installed a bit closer to the bearing. Or that when reinstalling they cleaned the mount surface, and possibly blew out the dust from behind the bearing.

It's possible that the "bad" sensor was just bad, or bad quality in the first place. I've gotten DOA sensors from honda before, and I trust their QC much more than I do Chrysler.
 

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Got it fixed today.

Picked up the original item off Amazon: Mopar 68174026AC Abs Wheel Speed Sensor

My mechanic installed it in an hour or so. All lights immediately went out.

Lessons learned:

1. Use AlfaOBD (Demo is fine) to get sensor readings in real time. Note that you have to hit the actual 'Connect' button on the ABS module page. Drove me crazy again today as I forgot from weeks ago when I tested it.

2. The original part that ends in AC works. Parts shops will try to sell you the updated sensor ending in AD. After reading the other thread, I didn't take that chance.

3. Always disconnect your humidity sensor, even if it's not the actual problem.

ga2500ev
 
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