Good aft-- no, amazing afternoon ladies and gentlemen! Just solved my issues with my 2010 TDI treg. Let me provide a back story.
Back in the fall of 2023 I coerced my parents to check out their first VW which was 2 hours away in cottage country Ontario. Listed for 11,000CAD, pictures looked pretty good. We got to the peoples house and they couldn't get it started(it had been sitting). When it was finally running it started clicking the shifter lockout and dash lights flickering randomly. We actually decided to take it for a test drive and the issues basically got worse. Ended up having it towed home for a steal of 3 grand! Car was in limp mode, stuck in 3rd gear and dash was lit up like a Christmas tree.
We searched the forums, tried finding the wiring loom splices under the drivers footwell and other things until we gave up for a while. We ended up taking out the dash, seats, center console and lifting the carpet. VW updated the body harness in 2009 I think, and it has different issues. We got vcds and learned how to understand that (I also manual swapped an audi during this time), and after scanning, we had a very long list of codes from basically every module, many of them being "no communication". This basically means that that module is either not powered, faulty, or the communication wires, or Canbus wires have an issue. I had a big clue that it had to do with wiring because of the random flashing of lights and sounds. This really points to bad connections. I fixed the issues today. The canbus wire splices were the issue. Theres one or two on the drivers side close to the b piller on the floor in the loom, and then 2 MAJOR splices on the passenger side wrapped up in the harness going to the rear passenger door. They were completely corroded, and fell apart into crumbs when I took the tape off. Theres also a black w/blue wire splice that has 4 wires coming together in the same place that handle B+ for the tcm. Btw for anyone who needs to know, the canbus are as follows: orange w/ black & orange w/ brown is powertrain canbus which mainly connects to the ecu, tcm, transfer case module, and abs. (also more stuff but theres a canbus self study avalible out there.) orange w/ green & orange w/ brown is comfort canbus which connects to interior stuff and doors etc.
Theres also 3 ground cable splices in the loom under the passenger seat that should be checked. I hate VW for their wiring.
In the end, we saved a treg from scrap, as this is obviously a difficult and time consuming repair. It would never make sense if we had sent it to a shop.
Back in the fall of 2023 I coerced my parents to check out their first VW which was 2 hours away in cottage country Ontario. Listed for 11,000CAD, pictures looked pretty good. We got to the peoples house and they couldn't get it started(it had been sitting). When it was finally running it started clicking the shifter lockout and dash lights flickering randomly. We actually decided to take it for a test drive and the issues basically got worse. Ended up having it towed home for a steal of 3 grand! Car was in limp mode, stuck in 3rd gear and dash was lit up like a Christmas tree.
We searched the forums, tried finding the wiring loom splices under the drivers footwell and other things until we gave up for a while. We ended up taking out the dash, seats, center console and lifting the carpet. VW updated the body harness in 2009 I think, and it has different issues. We got vcds and learned how to understand that (I also manual swapped an audi during this time), and after scanning, we had a very long list of codes from basically every module, many of them being "no communication". This basically means that that module is either not powered, faulty, or the communication wires, or Canbus wires have an issue. I had a big clue that it had to do with wiring because of the random flashing of lights and sounds. This really points to bad connections. I fixed the issues today. The canbus wire splices were the issue. Theres one or two on the drivers side close to the b piller on the floor in the loom, and then 2 MAJOR splices on the passenger side wrapped up in the harness going to the rear passenger door. They were completely corroded, and fell apart into crumbs when I took the tape off. Theres also a black w/blue wire splice that has 4 wires coming together in the same place that handle B+ for the tcm. Btw for anyone who needs to know, the canbus are as follows: orange w/ black & orange w/ brown is powertrain canbus which mainly connects to the ecu, tcm, transfer case module, and abs. (also more stuff but theres a canbus self study avalible out there.) orange w/ green & orange w/ brown is comfort canbus which connects to interior stuff and doors etc.
Theres also 3 ground cable splices in the loom under the passenger seat that should be checked. I hate VW for their wiring.
In the end, we saved a treg from scrap, as this is obviously a difficult and time consuming repair. It would never make sense if we had sent it to a shop.
