OK it is not the ECU and the hall effect could influence fuel delivery as the ECU does not command the fuel pump on (other that the pre-charge at key-on) until the engine is running and the only way it would know is the hall effect sensor. This is where a GS-911 would come in handy. May want to check the connector in the lower electronics box.
I have never put a meter on one so I don't know what to expect. You could compare resistance measurements with your friends. Be sure and swap the red and black meter leads and check on the "diode" setting on the meter as these are sold state devices.
A simple way to check if the hall-effect (ignition) does trigger during engine rotation is the following method:
Read carefully, then click to see a short video on YouTube:
Should hear the fuel pump priming when you turn the ignition ON - also you should hear the 2 to 3 seconds pump priming every time you move the kill switch from left (or right) to center position
Fuel delivery must continue when the engine turns: this can be checked based on the fact the Motronic use the hall-effect-sensor signal to continue running the fuel pump.
Although I have never seen a K1200 engine starts during this test, you are potentially vulnerable because of you position - BE VERY CAREFULL when you try this. Also, if you are too forcefull (or push too hard) THE BIKE MAY FALL FORWARD from the centerstand.
1) Bike on centerstand
2) Manually put transmission in 5th gear for K1200LT, video was shot on a K1200RS so there is a 6th (might required a bit of wheel rotation to mesh the gears)
3) Ignition ON and Kill switch in the normal RUN (center) position
4) Behind the bike, on you knee, rotate the rear wheel (forward bike rotation) - you are working against the engine compression so you will need both hands. DO NOT put you hands inside or against the mag wheel (in case it would start), just put one hand on each side of the tire, press and rotate forward.
The relationship is not 1:1 (wheel rotation compare to crankshaft rotation)m but for 1 full turn of the wheel, you should hear the pump priming cycle at least 3 times (at hall effect cycles).
If you have Hall-Effect signal, then you should have spark, unless coil is damaged or unplugged.