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mk4 Jetta VR6 ECU - Can you unplug and replug in without issue? (OBD Port Issue)

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2001 VW Jetta VR6 - 6 speed manual


I am in the process of trying to diagnose a DATA BUS short (OBD2 port will not work). Can you unplug the ECU, turn key on to test OBD port and replug the ECU in after without issue? Its a simple question but I cannot find a clear answer anywhere. 


Am in the process of trying to make a list of modules to check. ECU keeps coming up but there is no way I'm unplugging it without knowing if that will damage it or clear it etc. 

ABS module and Comfort module are on the list but have not tried yet (taking a damn break from this thing - getting ready for round 2)



(bought car at auction, runs ok but kinda rough. Starts absolutely fine. Can drive OK but bad lifter noise. Has CEL but cannot communicate through OBD port)

Just to clarify, port HAS POWER whether key is on or off.

Check engine light is on - ABS light is on - Traction control light comes on once in a while - Washer fluid sensor works fine (light comes on when low)

Have checked radio K lIne, is fine (4V-ish)

Have checked and replaced cig lighter fuse and #4 fuse I think? (were blown) Still no COMM

Both fog light and HID bulb filaments were fried (had HIDs, have since removed and am waiting on plug & play replacement headlight assemblies because old assemblies were illegal)

FYI- Intake shift rod was not source of engine noise, neither is the chain (motor was swapped 10,000 km ago, 4000 miles or so) Lots of stuff was replaced with motor swap. 


Am making progress with this car but I REALLY need to get this OBD port working. Any tips would be appreciated. 

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