Hi and thanks for stopping in to see us.
The First code U0121 Lost Communication With Anti-Lock Brake. is something I see often where there are other things going on and system is "busy" dealing with other trouble codes. Other times I see it when the ABS system has truly lost communications all together (its rare but it does happen) .
The second code, U0415 Invalid data received - anti-lock brake system is also something I see often and could be related to something else being wrong and in itself just a symptom.
The third code you gave "P0850 Park/Neutral Switch Input Circuit" is the one I would tackle first before sweating too much about the ABS codes.
The P0850 Code means that the Power-train Control Module (PCM) is confused about the state of the transmission. It is not able to tell if the transmission is in park, neutral or in gear. Typically this is caused by a faulty neutral safety switch.
See the link below:
Fixing something like this is very inexpensive and can take you about 15 to 20 minutes to do.
Tuesday, November 26th, 2019 AT 5:21 AM