Yes, it can just be one or more of the ABS wheel speed sensors gone bad. However, if your car is randomly losing the speedometer while driving that would lead me to the Vehicle Speed Sensor as that is the sensor that sends vehicle speed to the speedometer and that failing would most likely cause all of these issues as well. A bad ABS wheel speed sensor should have no effect on the speedometer. My speedometer never acted up when the ABS wheel speed sensor went bad. That makes me think it may be the Vehicle Speed Sensor located on the transmission somewhere. All of these sensors work together in the ABS ESP/BAS system so a failure of any component/sensor shuts the whole ABS ESP/BAS system down as well as the cruise control and screws up the auto deploying and retracting spoiler that is tied into vehicle speed and this system. I've never changed my Vehicle Speed Sensor on the transmission but another posted, "The speed sensor is mounted on the electrical plate located just above the sump pan. Remove the pan, remove the plate and replace the sensor if required." Maybe others can confirm this.

I certainly would clean the ground at the body frame and check the copper wire at the battery terminals and such but issues caused by a weakened battery or a bad ground usually result in an odd no-start situation with the dash lit up like a tree or problems that fix themselves once the car is running and the alternator is feeding 13.7V or so to everything. A weak battery or ground shouldn't be throwing specific codes indicating a potential problem with specific components that would cause the exact problems you are experiencing.

I wouldn't let someone sell you an entire new ABS module right away as a relatively cheap sensor(s) is most likely the cause of your problems. Before I inherited my XF from my father the Chrysler Dealer replaced the ABS module TWICE when the same problems presented and it was under warranty. After it was no longer under warranty my father just ignored the lights on and drove it for years like that. When I got it I took it to a reputable independent shop and they fixed all the mess replacing a simple wheel speed sensor. I'm convinced that Chrysler dealer kept billing Chrysler for ABS modules under warranty while replacing speed sensors!

I'm guessing you have Check Engine Light on, ABS light on, ESP/BAS on, and the traction control lit up in the middle of your speedo + your rear spoiler issue with that light flashing on the dash switch and your cruise control is not working. If you are going to work on it yourself and can't get the higher level codes that diagnose the exact issues in the ABS system I'd start with the Vehicle Speed Sensor and then if that didn't work replace all 4 wheel speed sensors as they are all going to fail at some point anyway (you wouldn't change only 1 plug or coil that failed). For the price of all 5 of those sensors a reputable independent European shop will probably charge about the same price just to diagnose the problem and replace 1 wheel speed sensor. So, I'd do all that before taking it to a shop and if that didn't work then I'd take it to a shop that had the right ABS diagnostic equipment because they charge to use that higher end equipment (and they should be entitled to charge more for that equipment they've invested in).