So, I just purchased an 2001 A6 Avant to haul stuff in style. When I got it home, I noticed the inside lamination of glass of the windshield is cracked in the black portion of passenger side at the rain deflector. Two days later I get the red bar through PRDN. Peruse this forum which leads me to the TCU. It was damp down there but inside of box was dry. Take out the TCU and dehumidify for 24 hours, reinstall TCU, all OK for a day then back too a red bar. Get a used TCU off of eBay for $82, install it, all OK for a day then red bar. All this time, the interior lights above the sun visors, the key in ignition dong, and the rear gate light do not work. Also neither drivers side door open indicators light on what's left of the LED display. Removed the lower steering wheel surround to hook my GPS to the accessory circuit on a terminal block down there (bastards hid a few fuses back there). When I was reinstalling the cover, wiggling and bumping about lit up the Odometer and Clock displays. Also, when I remove the interior light fuse, the key in the ignition dong starts working. Another note: once when I slammed the door right, the alarm light by the drivers side door lock button started blinking for the first and only time. NOW HERE'S THE GOOD BIT: When the LED says I'm in "Limp Mode," I'm not. Auto shifts through all 5 gears, and I can manually up and down shift in TIP mode. Could a short in the cluster be causing all these issues? If I bump and bang around there, things turn on and off. Also, I learned today that if I cycle ignition key on and off enough, I can get rid of the "Limp Mode" red bar. That's a symptom of a bad neutral safety, right? After a week, I get a check engine light. Bought a VAG405 and retrieved codes 16534 (P0150, Ox sensor), 17584 (P1176, Ox sensor), and 18010 (low voltage) on the engine. All I get for Transmission is 18158 (P1750, low voltage). Low voltages are from battery disconnect. Rain deflector was out of it's channel on both sides and channel was filled with debris. Assuming some idiot tried tried to hammer it in and cracked the windshield. So, what do you think, bad ground, bad neutral safety, or two bad TCUs?