My 2019 4WD Limited went nuts today

[37ford]

My wife was in town while I was at home, and I suddenly got 4 FordPass notifications on my phone:

Pre-collision assist not available
Hill Start assist waring
Hill descent control fault warning
Antilock brake fault

I was worried something bad had happened, but my wife said a bunch of lights just came on. The car seems to run fine, but I hooked up my computer to check the error codes:

U0415:00-0B Invalid data received from ABS control module A
C0031:24-2E FL wheel speed sensor
C0031:38-AF FL wheel speed sensor
C0031:4A-AF FL wheel speed sensor
U0418:86-AF Data invalid from braking system control module A
U0415:00-2F Invalid data received from ABS control module A
U0415:00-2A Invalid data received from ABS control module A
U0415:00-2F Invalid data received from ABS control module A

There seems to be a bit of a common theme...

 

[wakeboarder]

Other people have linked similar instances to a failing battery.

 

[37ford]

Interesting. I just replaced the factory battery before a long road trip. When my computer was hooked up, I noticed that it was reading only 13.2v while running.

 

[2020-MAX-Limited]

Interesting. I just replaced the factory battery before a long road trip. When my computer was hooked up, I noticed that it was reading only 13.2v while running.

The voltage while running is a measure of the charging system, not the battery. You should measure the voltage of the battery with the engine off, but ignition on. Put the ignition on by pressing the power button without pressing the brake pedal.

 

[wakeboarder]

A bit more thinking about this. Everything is associated with the ABS module. So it may not be a battery issue. Could be a problem with the ABS module or the connection to it.

All the assist features rely on that module for data.

I have had other module errors that never or rarely re-appear.

 

[37ford]

My battery is 12.45v after sitting all night.

I went ahead and ordered a wheel speed sensor. That’s cheap and easy enough to replace, and I’ll go from there.

 

[Yupster Dog]

Interesting. I just replaced the factory battery before a long road trip. When my computer was hooked up, I noticed that it was reading only 13.2v while running.

You should be getting At least 14v while running.
It could be a voltage drop from a corroded connection or the alternator.

Do a "Voltage Drop Test" to check all the battery cables and connections.

Then you can take the truck to an auto parts store like Auto Zone. They can check the battery/alternator system while still on the vehicle.

 

[2020-MAX-Limited]

You should be getting At least 14v while running.

Well, with the smart battery management system, the charging voltage will drop when "the system" thinks the battery is already charged, so you won't see a constant 14+ volts when running.

 

[AAOO]

Did you register the new battery after replacement? I was having similar electrical gremlins in December but after the replacement they went away.

 

[Mr Big]

Did you reset your BMS after replacing the battery? Did you purchase an AGM battery? If not, you can get all sorts of bad readings. I suggest reset bms, then clear all error codes and monitor to see if the errors come back.
I had an incident one time where I was demonstrating sport mode to a friend. I changed while driving, and the next day it popped catalytic converter, oxygen, and a few other codes, causing the service engine to come on. I knew they were false positives, so I reset the error codes and they never came back. I'm not saying this is your problem, but changing a battery without report can cause quirky things.

 

[Left Coast Geek]

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).

 

[37ford]

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.

 

[37ford]

Youtube video of errors

 

[Left Coast Geek]

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.

 

[37ford]

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.

 

[37ford]

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.