My 2019 4WD Limited went nuts today

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Left Coast Geek

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if these problems persist and/or more erratic problems show up, check out the grounds. measure the potential (voltage) from the battery - terminal to various places that should be grounded with the car running and various loads on. engine block, alternator body, chassis frame, etc etc. ground potential voltages should all be less than 0.1V (100mv).
 
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37ford

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I changed FL wheel speed sensor today, and I still get the same error codes. They consistently pop up immediately on start-up. Looks like I'll be doing my most FAVORITE thing in the world...chasing electrical gremlins. I had seen an older post about the same issues, and someone mentioned a loose ground in the pass kick panel.


I tried to reset the BMS, based what the internet suggested, and I couldn't get the battery light to flash. So, I don't if it worked or not. Another site said to simply disconnect the negative lead for 20 minutes or so. I did that a couple times.

I even put the old battery back in it for a couple days.

Yes, I did get a new AGM battery. I had no idea what that was, but that's what I have.
 

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AGM stands for Absorbed Glass Mat, they are sealed lead acid batteries, and the acid is held in a glass cloth mat between the lead plates. Ford specifies them for our Expeditions.
 
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37ford

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I was able to use my scan tool to graph the wheel speed sensors while in motion, and the FL still shows zero signal after replacing. So, it’s either the hub or a fault in that circuit.
 
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37ford

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Checking back in with an update.

I was able to use an old speed sensor to create a jumper wire to check and isolate the problem to the hub/sensor. I changed both, and all the codes went away.

The old hub seemed fine. It's amazing how that one part created so many error codes.
 
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