Question about 2000 Volkswagen Beetle

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We are unable to communicate with the emissions computer

2000 Beetle Gasoline engine. Plugging into the data connector under the dash does not produce any communications. We took it in to a shop to get a safety inspections sticker, and they could not get any readings. The wiring diagram shows a device called a Data Link Connector, but it only shows two conductors (Gray/White & Green/Gray) connected to it. The connector under the dash has 10-20 pins on it. Is the Data Link Connector on the drawing the purple connector under the dash? Any idea what pins the two conductors should be connected to?

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  • hriddle Dec 14, 2008

    Yes. When the shop plugs its scanner into it, nothing happens. I searched some of your archives and found an incident from 2002 where Art mentioned that VWs with an aftermarket radio can interfere with the data flow. When I mentioned that, my son recalled that the person we bought the car from mentioning that we would have to remove the radio to pass the safety inspection test. So I think I'll unplug the radio and let them plug the scanner back in to see what happens. I'm not sure why the data passes through a radio connector, but I'll take his word for it. In my wiring diagram, there are only two conductors that show being connected to the data link connector, so I'm not sure whether there are other conductors involved here or if they are left off of the diagram for some reason. Either way, intuition tells me that disconnecting the radio from its connectors will restore data communications. And Thanks for helping out!

  • hriddle Dec 19, 2008

    Disconnecting the radio from the wiring harness allowed the Scanner to connect to the data link with no problem. I tried to determine which conductor did not need to be connected to the aftermarket radio, but did not see the color that was labeled as the data conductor in the bundle. It was dark and the cable was tight, so I couldn't tell much about it.

    Regardless, unplugging the radio allowed it to be tested and pass a safety inspection. Thanks for the link to megaupload. The Haynes manual I bought is incomplete and tries to cover too many models with one set of diagrams.

  • hriddle Dec 29, 2008

    I tracked the data link on the wiring diagram and noticed that one of the conductors does in fact go to the radio connector. When the aftermarket radio was hooked up, I'm sure the installer didn't know what to do with it and probably connected it to something that screwed up the whole data bus....but only as long as the radio connector was plugged in. I'd bet it just grounds out the line. Anyway, then NC safety inspection process requires an emissions test that needs the data bus to work. Either way, it passed once I unplugged the radio.

  • Anonymous Mar 26, 2009

    My 1998 Dodge Durango will not communicate as well. They checked the fuses, which are fine. I bought the car from a dealership 4 years ago.I am unsure if it has an aftermark radio. The radio has not worked since 2007.

  • Kevin Blair
    Kevin Blair May 11, 2010

    the vw scan tools allow for advanced features which is why the system can connect to the radio.

    check this link out it has more info on the wiring etc..

    how to use megaupload

  • Car Fixer May 11, 2010

    Does the connector look like the picture here?



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Yes it is the purple connector. Any generic OBD II scan tool should be able to pull up P codes. Sometimes you will get an enhanced DTC and no code will be given. If there is a shop in your area with a Launch X431 scan tool I'd go to them and have it scanned. Any Auto Zone can scan it for you to. Also I have never had a problem scanning any VW with an aftermarket stereo. Is your MIL on? If it isn't on I don't know why they would want to run a scan for the safety inspection.

Posted on Dec 28, 2008

  • John Weathers
    John Weathers Dec 29, 2008

    Good glad it passed. Here in Austin TX they just probe the tailpipe for emissions and will only scan the ECU if the MIL is illuminated.

  • Leslie Morales
    Leslie Morales Nov 26, 2013

    I'm having the same problem with my 04 Beetle, the VW dealer told me that I won't be able to inspect my car without the original car factory.



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