Any JK ABS failures?

NatersXJ6

Explorer
So, I’m at my wits end. I may be making irrational decisions.

A few weeks ago my 2014 JKUR at about 162k miles suddenly started sounding a chime and flashing a bunch of warning lights while driving on twisty mountain roads. It would cut power, the Speedo would fall toward zero, and various lights, including ABS, Brake, Traction Control, Sway Bar, etc… would flash. Everything instantly returns to normal with no loss of speed or shifts or anything else. It repeated on 1-10 minute intervals for 80 miles on the way home. Stressful drive.

After a couple of key cycles it would go away and not return for days or weeks. Codes were mostly in the ABS module and included Battery Voltage High, Brake switch stuck on 50%, Brake circuit 1 performance.

I verified correct tire pressures, gear ratio, wheel speed sensors all report and match, and steering is centered.

The problem has gotten progressively worse to the point of almost undriveability. I’m sticking close to work now. There are still random runs of 30-50 miles with no issues, but more likely is 2-3 miles until it starts up and then lucky to make it 1 miles between issues. 1/2 mile is more likely.

While scanning and watching data, I realized that the ABS module thinks its supply voltage is randomly fluctuating from 12.6-15.7 volts several times per minute, no pattern, just all over the map. So I thought maybe a bad voltage regulator at the alternator, but that output is rock steady at 13.79 V. I also replaced the brake switch because it was $18 and seemed like easy troubleshooting. It was sticking, but not the cause of the issue.

Interestingly, when the speedo drops, the PCM sees Vehicle Speed go to zero for a fraction of a second, but all of the other things that report vehicle speed (all wheel sensors and transmission control) don’t see the fluctuation.

So, most of the internet troubleshooting seems to say “Swap the ABS module and life will get better”…

But….

Jeep discontinued the module for the early 2014 builds and the late 2014 (theoretically different) are backordered since 2019. I found one that claims to match on Amazon for $800. Ouch! There is a place called Module Master in Idaho that claims they can rebuild? I haven’t called them yet.

I turned off the ECS with JScan, but the problem is still happening, just no chime, so much less annoying. All driving and shifting functions are still fine. I tried unplugging the Module, that doesn’t work, because you can’t shift out of first, even though you can drive.

Has anyone else dealt with similar? What did you do? These modules seem to have gone into dozens of car makes and models. Could we really be left high and dry by multiple manufacturers after less than 10 years?
 

Dan Grec

Expedition Leader
Does it only happen when you're going around a corner, or does it happen on perfectly straight sections of road too?

-Dan
 

NatersXJ6

Explorer
All conditions when moving. Not associated with cornering, doesn’t appear to be wheel speed related (near perfect matches from all sensors) and there is no randomness or variability in the steering wheel angle signal, so not expecting a clock spring problem. I’m also in a warm/dry environment, so no corrosion anywhere.
 

Dan Grec

Expedition Leader
All conditions when moving. Not associated with cornering, doesn’t appear to be wheel speed related (near perfect matches from all sensors) and there is no randomness or variability in the steering wheel angle signal, so not expecting a clock spring problem. I’m also in a warm/dry environment, so no corrosion anywhere.

Hmm, corrosion or a loose ground were going to be my next suggestions.

My only thought is see if you can get the ABS module from an auto wrecker.. or keep researching and see if you can use one from a different model year.
I'll be really interested to hear what it actually is..

-Dan
 

NatersXJ6

Explorer
I ran a continuity test from the ground wires to battery negative post. There don’t seem to be any opens but I don’t really talk now what the resistance should be. Next time I unplug the module I will continuity test from pin to battery negative post.

Today I watched steering angle while driving to see if I could truly rule out clockspring. It seems to move around a lot, but there doesn’t seem to be any correlation with the chime and the issues.

I’m trying to attach a short video, not sure what the file sizes will say about that.

I only have two more days til Amazon drops the new module, so maybe 80 more miles of driving. It has been getting progressively worse for weeks, so I’ll probably make it.

This is a very interesting and insanely annoying failure in what should otherwise be a perfectly fine vehicle!

In other fun observations, the ABS reported vehicle speed doesn’t just drop to zero when the problem happens, it also sometimes jumps to 318 MPH. Always 318 or 0. All the wheel sensor speeds remain the same. As Jeep people know, even if you shove the Jeep out the back of a cargo plane in flight, it reverts to its natural speed of around 35-40, so 318 is out of the question!
 

m-l_johnny

Active member
I recently had a very similar situation with my 2017.
Did some interwebz searching and came across a fair amount of info referring to dirty/ loose battery terminals. I removed and cleaned the connections, made sure they were sufficiently tight and gooped them well with dielectric grease. The issue went away.
 

NatersXJ6

Explorer
I recently had a very similar situation with my 2017.
Did some interwebz searching and came across a fair amount of info referring to dirty/ loose battery terminals. I removed and cleaned the connections, made sure they were sufficiently tight and gooped them well with dielectric grease. The issue went away.

That is interesting. I did “check” them, and they are tight, but I can certainly pursue the free options first and spend a little time with the Dremel and a wire brush making them perfect. I’ve found that they don’t truly tighten any longer, simply due to design of the little sheet metal clamp that Jeep used, and have thought about replacing the cables with something more robust.
 

Hegear

Active member
The battery could be the problem, I have experienced the same thing. Also have you tried taking the fuse out of the abs system? The abs light will be on but everything else should function correctly.
 

NatersXJ6

Explorer
Wow. I feel like it it too soon to say, but definite progress! I found hidden corrosion in the female threads of a screw-on battery post. After carefully polishing every battery or power connection I could find and continuity checking every ground identifiable on the wiring diagram, I did not find any high resistance or open connections.

I also drove to work today with zero warning lights, alarms, or issues for the first time in weeks.

I think the Jeep knows I ordered an ABS module and is testing me. If I return it, the problem will likely come back!

Thank you to those encouraging me to make an additional run through the battery connections!
 

NatersXJ6

Explorer
After several days and close to 800 miles, with at least 1/2 on crazy winding mountain roads, I’m pretty confident that the threaded connection corrosion was causing the issue. I’ve had zero problems, and two successful “proper” abs activations as I was braking hard on bumpy corners. So… thank you again to those that suggested a focus on battery connections. You saved me $800 and doubled that down on learning experience!
 

ChasingOurTrunks

Well-known member
Glad you fixed it Naters - for what it's worth the exact same thing happened on my 2013, and a good scrub of the battery terminals followed by snugging them up fixed it for me too. They seem to be very sensitive to that so hopefully one more person saying "that fixed it for me" gives you confidence in the miles ahead.

Also I spoiled myself by getting a rental Wranger for a work trip that was under 24 hours...I love my current rig, but in that time I got 3 jeep waves, felt every bump on the road, and had to constantly make sure it was staying pointed in the right direction with micro adjustments to the wheel -- and I loved every single second of it and it made me miss my old Rubicon something fierce. It is indeed "A Jeep Thing"!
 

AggieOE

Trying to escape the city
Yeah I didn't realize my terminals were loose but I had a similar situation a while back and reset them and sure enough.... issue went away. Super weird.
 

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