Technical Help me solve this mystery

[Jtebs]

Been trying to figure this out for over a month

I have a 2012 fiat 500 Pop 5 speed manual. It hit 70k miles this past summer (currently at 73k). It has been in my family since new purchased in January of 2013 (leftover from 2012). It was my mom's car for a couple years, then I learned to drive in it and it was my first car, and I still have it. I've been driving it since 2015. Until now it has been dead reliable. Never given me an issue before and I absolutely love the car.

So in late October I was on the freeway on my way to work and my check engine light came on, along with my ESC light and ABS light.

I keep a simple scan tool under the passenger seat so I read the engine code when I got to work and it was an evap code for gas cap. I cleared it and it didn't ever come back.

The ABS and ESC lights remain on, and every time I start the car I also get a warning that hill start is unavailable.

I have a more advanced scan tool in my garage that can read ABS codes and it reads no faults. I took it to my local Chrysler/Dodge/Jeep dealer and their scan tool also says no faults with the ABS and ESC systems. We t to a local mom and pop mechanic shop, same result on their scan tool as well

So I took to the forums to find solutions, here is what I've done so far in no particular order:


Replaced all 4 wheel speed/abs sensors

New pads and rotors

Checked for wiring issues in the boot to the hatch

Replaced battery

Replaced Earth Strap

Cleaned and sanded the supposedly problematic grounding points on this year of the 500

Replaced brake light switch

Flushed and replaced brake fluid

Reseated wiring harness for the ABS module

Rotated tires

Double checked pressure is correct

inspected for treadwear

Checked wheel bearing condition

Got an alignment




None of this has fixed the issue and with no codes pulling on any scan tool I am stabbing in the dark and I am completely out of ideas.

I got new tires too (General Altimax) but that was because they were wearing out, not an attempt to fix this issue.

It runs and drives perfectly fine, and I don't need hill assist and typically drive with it off anyway. But I really want the lights to go away and I want the piece of mind of kno6tgese safety systems work.

Also, my state inspection is up at the end of this month, and to pass I can't have any warning lights. So if I don't figure this out soon I won't have a car I can legally drive to work anymore.

I love my fiat, please help me save her!

 

[bugsymike]

I would start with access to a good diagnostic tool such as Snap On Zeus at a garage, or a full version of MultiEcuScan for Fiats that many here on Forum use as it should be able to show "Live Data", I see you have changed the ABS sensors at the wheels which is a common source of the problem, though a good diagnostic tool will show exactly which wheel is the area at fault assuming that is the case, rather than just changing all of them which is throwing money away.
Note it can still be an ABS issue at a certain wheel from the rotor that activates the sensor, magnetic or otherwise.
By the way I am guessing you call the brake discs rotors which is not what I mean, many modern systems use a magnetic vane/rotor as part of the end of the wheel bearing, so if that is at fault you could fit a 100 ABS sensors and still have the issue until the wheel bearing was replaced.
Another small point when ABS sensors are replaced it is not unheard of for the "mechanic" to clean the hole that it fits in using a "magnetised " screwdriver, this action can destroy a perfectly good wheel bearing type ABS sensor.
I have a credit card sized tester by SKF Bearing company that when held against the bearing will show if it is good or bad.
Another area that can cause problems is the wire from the ABS sensor in the wheel arch leading up to the ABS pump computer/ecu under the hood/bonnet.
Generally in all those cases a decent diagnostic tool will show it up, or give an error code for the ESP side if that is the cause.

 

[jackwhoo]

Read live data of wheel speeds they should all be very similar