OBD2 Linking Failed!!!! Help me out

thejustinmthejustinm Member Posts: 3
edited September 2016 in Volkswagen
Ok so a couple weeks ago I tried to check the codes on my 05 golf and it came up with "linking failed". I've been able to read codes this obd2 reader on my car fine until now. Cigarette fuse is fine, and I checked pins 4,6,7 and 16. They are all fine. I disconnected the negative battery terminal and hooked up a test light to the negative post on the battery and to the negative terminal. This causes the light to turn on meaning that somewhere there is a short? Maybe this is causing communication problems between my reader and the ECU? I've disconnected each fuse while the light is on to try find which circuit is shorting but the light stays on the whole time. I've don't the same for all the relays in the car. I traced the short to the small fuse box on top of the battery which has a wire called "s176" that goes to the main interior relay panel. From there, there's two smaller wires which bring power to the interior fuse box and I don't know where the other one goes. So far I have disconnected every door, the radio, heated seats, sunroof, and a few other things to try find the short circuit but haven't found anything. If anyone has any idea what I should do next, or if ive missed something please let me know.... Thanks

Comments

  • thecardoc3thecardoc3 Member Posts: 5,792
    Trying to use a test light to check for a parasitic drain doesn't work with today's cars. When you disconnect the battery and then connect the test light in between the cable and the battery post, you wake up but don't completely power a number of modules on the car. That keeps them partially awake and drawing power waiting for a command to go to sleep which never comes.

    As far as the tool not communicating, you need to try a professional level scan tool to see if it can connect to other modules besides just the engine controller. If so pull codes from all of tem and see where that leads, however since you disconnected the battery, you may (probably) have already lost information that could have been real helpful.
  • thejustinmthejustinm Member Posts: 3
    I brought it to my mechanic to clear an airbag light. He tried 2 different scan tools and neither worked
  • thejustinmthejustinm Member Posts: 3
    How should I go about finding the short? @thecardoc3
  • thecardoc3thecardoc3 Member Posts: 5,792
    Why do you believe there is a short?
    What voltage do you measure on Pin 7 to battery negative?
    What do you measure on pin 6?
    What do you measure on pin 14?

    What do you measure between pin 6 and 14?
    With the key off, and no power on pins 6 and 14, what is the resistance between pins 6 and 14?
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