I'm looking for some advice troubleshooting my 2012 VW Jetta GLI Autobahn. I just replaced the ignition switch and cylinder housing and it won't start. When I turn the key all the lights come on like normal but when I turn it all the way instantly all lights shut off and I get nothing no crank whatsoever. I put a code reader on it and get a U 0101 code which says lost communication with the TCM. I cleared it tried it again and got the same thing code and all. Next I checked all the fuses and they are all good and since it was getting late I decided to pull my battery and charge it overnight because I had been waisting a good bit of battery I life I feel the last couple days just leaving the door open and interior lights on while working plus I just wanted to eliminate it as a possibility because at the moment I dont have a multimeter. Any thoughts or help would be much appreciated and I will update it turns out the battery changed anything.