Problem running Diagnostics 99' Passat

[rotax800]

Hi guys.

I got a 1999 Passat Wagon 1.9 TDI. The problem is that everytime i connect a vag-com /vag-scanner i kill the unit. I have already done this 2 times, until i found out that something is wrong with my car.

I have googled this, and found t"he solution" on the Ross-Tech website. Its called the After Market Radio Problem. I checked the connectors behind my stereo - but the one that has to be removed is already removed.

The site tells me to measure the voltage between pin 4 (ground) and 7 (k-line / k1) on the diagnostic connector. The measured voltage is 12.5V. And it describes how to fix this problem, by disconnecting the black wire from the radio harness.

The wire is not connected. Where does the 12.5 volts come from? EDIT: Just measured: The Voltage is 10.7V

Where do i start?

Thanks.

[stevegrass777]

Have you tried to disconnect the radio completely.

[rotax800]

Yes.

Disconnected the radio and removed it. Voltage remains between pins 4 and 7 on the diagnostic connector. (And the wire taped to the stereo harness)

[stevegrass777]

How about pulling the fuse for the radio

[rotax800]

In the fusebox on the left side of dash? No. havent tried that. Will give it a go. back in 2 minutes. Stay tuned :Blush:

[rotax800]

Hmm. now im quiet confused.

I measured the voltage on the pins on the connector. 2,5V (?). I then connected a third party vag-com cable and measured on the print inside the cable, then i measure 11-12V ! I got the same results when the fuse was removed.

[rotax800]

Ok.

I have checked the voltages again.
And the results are:

10.6V with the ignition ON

2.5V with the ignition OFF

Any ideas?