02 T&C ABS issues
 

I have an 02 Town & Country that just had the ABS light light up today. I had the ABS codes read and couldn't get an answer on the next step.

code 04 Right Front Wheel Speed/Signal Malfunction
code 11 Electronic Control Unit Internal Malfunction
code 16 Over Voltage

Also on a side note when I bought this vehicle a couple weeks ago the battery was completely dead (would not even start to charge) and the Tachometer was and still is dangling straight down when the vehicle is off. it pegs itself against the back side of the "nub" when the vehicle is on like it wants to work. I don't know if this is indicative of anything or not.

I put in a new battery and it tests at 12.8v I went ahead and put in a new alternator just in case because the old one seemed a bit "loose" when I was putting on a new belt, I need to know absolutely certain my family is safe when I'm not there (I know I should buy a brand new car but this is not the answer I need)

Do I replace a speed sensor?
is the hub failing?
Do I replace the ECU?
Do I replace both? or is this a "thing" I should know?

speed sensor yeah hub no way of knowing we can not see it or driver it to hear any noises
ABS module more then likely yes has internal failure.