Join Date: Dec 2007
Location: Las Cruces, New Mexico
CEL and Codes U0101 and P0571... what did I do?
Alright, first the let me set the stage to the problem... I had hardwired my radar detector into the review mirror using a hardwire kit similar to the invisicord. Anyway, when I first wired it, I used a voltmeter to find a ground and +12v wires in the mirror. I connected everything and when I plugged the radar in, it powered on and then went into a "self calibration" mode. I turned the car off, and then on again and same thing occured with the radar, but then it powered off, and I couldn't get it to turn again. I rechecked the wires I jumped to and learned that the ground wire I used was grounded only while the car was off, however, when started, was no longer grounded... (that's weird). Anyway, I found a constant ground and everything with the radar works fine now.
Ok, now heres my issue. After that occurred, I started my car up to take a drive and a my check engine light came on. I did the key dance and it showed codes U0101 - Lost Communication with TCM and P0571-BRAKE SWITCH 1 PERFORMANCE. The CEL turned off after I had three drive cycles, but I'm not sure why those codes would have thrown, or what they mean exactly. I thought maybe I shorted something by not having a correct ground at first and a fuse blew in my brake lights, but they seem to work fine. It seems like the two events were interconnected, but I'm not sure how... especially with the TCM??? Any ideas on what I did, what it is, or if it's related to the miswiring in the mirror or not?