Dead OBDII port.

   #1  

houbaviy

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OK, here is a serious issue: I can't read any codes at all because the OBDII port is dead! The symptom is that there is no LED light on the actual VCDS cable socket even with the ignition on (the software says the interface has been found and there is no connection with the car). Also a basic OBDII tool doesn't power on and the problem is not with the tool as it works just fine on my Honda. This is on an Audi A4, B7. Could this be as simple as replacing a fuse? Any advice on which pins to measure with a multimeter? As always thanks for your help.

Hristo
 
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Uwe

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Could this be as simple as replacing a fuse?
It most likely is. Pin 16 should have +12, and pin 4 is ground.

DLC.png


-Uwe-
 
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houbaviy

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Potential difference between pin 4 and pin 16 = 0 but fuse #12 in the dash is intact ... At this point would it make sense to check for voltage between pin 4/12 and ground and +12 of ashtray for example, before tracing the connections in the wiring diagram?
 
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DV52

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@houbaviy: Are you are sure that "fuse #12" is the correct fuse that supplies pin #12 on the OBD port (what car is this)? Are you absolutely certain that fuse #12 is OK (have you actually confirmed continuity between the 2 x blades)? Is the OBD port the only electrical function in the cabin that is not working?

If the answer to ALL these question is "yes", then maybe eyeball the terminations and the state of the physical pins on the OBD port - might obviate the need for a WD

Don
 
   #5  

houbaviy

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@houbaviy: Are you are sure that "fuse #12" is the correct fuse that supplies pin #12 on the OBD port (what car is this)? Are you absolutely certain that fuse #12 is OK (have you actually confirmed continuity between the 2 x blades)? Is the OBD port the only electrical function in the cabin that is not working?

If the answer to ALL these question is "yes", then maybe eyeball the terminations and the state of the physical pins on the OBD port - might obviate the need for a WD

Don
You were right - it was the fuse, looks intact but no continuity. New fuse fixed the problem the OBDII port is working now. Thanks.
 
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