1998 Marea Weekend 1.6; was running fine, until I tried doing my first diagnostics:
--VAG-COM 16 pin cable
--DIY leads to 3pin: pin 16 to Bat+12, pin 4 to chassis Grd, pin 7 to R/W on my 3pin [presumably this is K-Line]. Didn't connect to the LtBlu/W.
--Program: Fiatecuscan with COM port set per instructions. (COM4 or 5, I forget which one.)
--Turned key to MAR: Only heard strange 'groning' sound from under boot/trunk (presumably from fuel pump.) Couldn't connect:'No ECU Response. Check your cable and port settings.' Then I tried pin7 to the LtBlu/W on my 3pin, same noise and message. Tried different ports.
--Disconnected diagnostics. Tried starting car, cranks (turns over) but still get groning noise from fuel pump area and now won't start!!
--DISCONNECTED NEG for 45 mins to 'reset' ECU. Same thing: cranks but only groning noise from fuel pump.
Q: Did I totally @&#% up my ECU? Did I merely (hopefully) blow a fuse? ANY IDEA WHICH ONE? Did I short a relay of some kind? We really need the car (our only one) and my wife is ready to roast something other than chestnuts on an open fire... Help!

UPDATE: Turned out to be the 5 amp fuse in the firewall fuse/relay box. Guess I blew it with an improper attempted DLC hookup.

Still need to know what the R/W and LtBlu/W wires are on the 3 pin connector and where they go on a 16 pin OBD plug...