Incidentally, you don't need a code reader, you can use a test light. Try following the methods described in this post.

The "test light" needs to be a single low power 12V LED. The diagnostic plug does not put out very much power so if you try something like a multi-LED 1156 turn signal bulb it probably won't illuminate.

Ha ha! No problem. It’s a K100RS though mate. Not a K1100 you’ve done that a couple of times and I just wanted to point it out so we’re not at crossed purposes.

Thanks Laitch, you’re a star for helping me out mate! Glad I chose to join the forum!

It's too early to start the party, Jonathon, but I would like to find lime and coconut frosting on the vanilla cake when it's delivered.   Wait until you meet some folks here who actually own a K1100. Glad won't come close to describing that feeling. 

Hi, thanks for replying. I’m just fitting up the replacement hall sensor now. Yes to the ignition amp question. It’s all correctly seated with paste on an earth strapped location to a clean metal surface. I have continuity checked the earths at all stages of the amp, heat sink and mounting plate but not measured the exact resistance. I’ll do that this evening.

Thanks for the diagnosis data. The diag plug is in the loom still minus the connected abs lead of course. However, sadly, I do not possess a fault reader for these bikes or indeed a bmw multi tester.

I don’t usually have to deal with fuel injection and ecu controlled motorcycles. This only my second k bike. Normally, I’m a classic Honda guy! :D Moving forward, I’ll get properly kitted out but for now, it’s just a multimeter I guess.

I’ll take all your suggestions on board and let you know when I have a little more data to share.

Thanks Laitch, you’re a star for helping me out mate! Glad I chose to join the forum!

After reading the manual from Laitch (thanks, that’s an awesome resource) I have got a very small output on both the 2 motronic outputs to the ignition amp. Only a fluctuating 0.20v on both during cranking. One is black (sw) on pin 2 of the amp connector and one is black/white (sw/ws) on pin 7 of the amp connector. The manual states that it’s a low voltage but does not say the exact expected parameters.

I am picking up a replacement hall sensor today just in case that’s the problem. I’ll keep you updated.

I should quickly add a side note; this is the 2.1 motronic and as such (I think) has no CO sensor. There is a lot of discussion regarding the Co sensor but there was visibly no sign of one on the bike’s exhaust system nor is there a connector for it on the engine loom. I think I’m right in thinking that the 2.1 doesn’t utilise this and has only the potentiometer. The manual seems to confirm this in a roundabout way but confirmation would be good.

Also, and I’m just shooting from the hip here but the only wire out of the engine loom I haven’t resolved is the brown/white (br/ws) from the diag plug to the deleted abs control unit. Does this perhaps need a resolution? This is the only abs related wire coming from the engine loom.

Thanks again.