Hi Shaw,
I have the exactly same problem.My 2004 also with H.I.S.S. (I'm getting FI code 25). I consider ECM fault, bike has only 18000Km (genuine) on the clock, no knock sensors connectors melted or corroded (they are not even dirty!). Under 1 ohm resistance between the cap and the ECM conne. (colours of the wires: Left sensor-Blue/Red,Right sensor-Black). I'm planning to run new wires from ECM harness to knock sensors, so I will be able to swap the sides to see if fault code change to 26. If not - then what, what else could cause this mystic fault?
Did you went for Carmo? Did you solved your FI light issue? I'm so disgusted, I own the bike for 2 months (1500Km) and until last week no problem at all. I still don't believe that the engine or knocks sensors could be "faulty" after 18000Km, so far my highest rpm was 6000 (that's how brave I'm!) ....to be honest: What could be the fault in the ECM which is fully working (worked) apart that FI shows code 25 above 4000 rpm. Bad Caps, leakage, cold joint? What else on circuits that operates in very low level voltages?
I rang to two authorised Honda service centers, here where I'm - Czech Republic. Their approach: Well it could be complicated and probably beyond value of the bike!!! I have paid more than 6000EUR two months ago for this bike!,... we don't have the service harness and tools for your bike and that age!!!...so if FI shows faulty know sensor, we will replace it and then we will see (they don't tell you that it will be at your cost)....try another Honda service. No, they don't wanna touch me bike, looks like nobody here have any experience dealing with St1300 neither this kind of issues. I now that Czech police forces had a few o these, until they have been replaced by BMW. I saw police one recently, passing by. Where they have been serviced? Or they (service centers) just swap the tyres and changed oil? This country drives me mad! I now it's not a country, but the people who living here and their "culture" which is still under bigger influences from growing russian population especially in Prague...English couldn't be moore accurate: Culture clash! Suddenly I have Czech passport hence I was born and grown here and our family lives here since we know, but I don't see many points that connects me with them (Czechs).
Back to topic: I have to help my self! Any remarks to my conclusions?
Did the Carmo fixed and returned "your" ECM or just ECM which has been factory refurbished (swapped refurbished unit) - I'm asking about H.I.S.S. functionality/pairing with keys?
Hopefully this weekend I will see if my theory makes any progress (swapping sides to see what the ECM will report)
Sorry to be novelist...any suggestion, reports, ideas welcomed!
Drive save!