Okay I have now tested disconnecting the passenger side connector for the tensioner. The same error "Gurtschloss Beifahrer (passenger seat belt lock)" with all the other same information still there still exists, but I also got a new error:

Zuendkreis ZK2/Gurtsrammer Beifahrer (Ignition circuit ZK2/Seat belt tensioner passenger)
-Fehler aktuell vorhanden (error currently exists)
-Widerstand zu gross (resistance too great)
-Fehler nicht sporadisch (error not sporadic)

The new error has the line "resistance too great" which you referred to earlier but the old error stayed unchanged with the "resistance too low". Could this mean the "Gurtschloss Beifahrer" is not directly related to the tensioner but there is some other mismatch between the seats?

__________________
09/2003 X5 3.0i
02/2003 X5 4.6is (non-runner)