dh53

Hello! I purchased a 2001 TT Roadster a few weeks ago and am new to this forum but have already found some great info here.

Short story: top suddenly does not open, Check Engine Light just came on, OBD-II does not work.

Long story: Today I went to get the emissions inspection on the car and while waiting in line decided to put the top down. It doesn't budge. I release the hand latch and press the button for the power top and absolutely nothing happens. When I move the switch to close the top I hear a click behind me, like a relay, but nothing happens. I don't really expect anything to happen since it is fully closed, but I thought maybe hearing the click could be significant. I tried moving the top manually, it moves easily. I immediately suspected a bad fuse but I can find no info on fuses for the convertible top in the owner manual or in the fuse box or online. Is it possible the motors for the top have no fuses?? I should add the top opened and closed without issue the last time I drove the car, maybe 4 or 5 days ago.

Fast forward 15 minutes and I pull into the inspection station. Here in Maryland an emissions inspection is simply connecting the inspection computer to the OBD-II port to check for fault codes. The technician could not get the OBD-II port to communicate with his equipment. He changed connectors and then had a supervisor come out and try and eventually the car failed emissions because they couldn't communicate with the OBD-II.

15 minutes of driving after leaving the inspection and the check engine light comes on. I drove home and plugged in my scanner and it will not communicate. I checked my scanner, it works flawlessly on 2 other cars. My scanner worked without issue on this car a few weeks ago.

I have no clue where to start to diagnose an OBD-II port which I guess must be fixed to figure out the CEL. Any possible way the top not working could be related?!

Any suggestions are much appreciated.

Walpole5

Whenever I read about sudden, multiple electronic issues I recommend checking the battery voltage. Our previous 2007 VW Eos had a bunch of strange problems suddenly crop up and it was the battery. The car still started fine, but the check engine light came on, the driver's window would only go up part way and other problems. New battery and they all went away.

dh53

Thanks for the reply. I have checked the battery, it is 12.4 Volts with the car off. When I turn the ignition switch to On (not Start so the starter is not on yet) it dips down to 11.9 or so. With the car running it measures 13.9 volts. The numbers without the car running seem a tad low to me so hopefully you are on to something.

Does the radio have a theft protect/lock out if I remove the battery? The car came without any original documentation so I have no idea how to recover the radio if this happens.