So, because I have too much spare time (have you noticed?) I've been trying to help a friend diagnose his 2003 R1 race bike over Facebook messenger. Crashed at the end of last year, had to have some welding done on the bike. He's trying to prep it for the start of this season and of course it's got issues. Key on, kill switch on and the fuel pump primes, it'll turn over if you thumb the starter but no fire. Worse, while the neutral light works, the rest of the dash stays dark. He's been working with a mechanic, so far the claims list is: Fuses - all replaced Harness - examined and 'pinned out' as good ECU - swapped with known good Dash - swapped with known good Voltage at dash connector - good Grounds - good The wrench has advised him to take it to a yamaha shop for a 'computer diagnosis' which I'm not aware was a thing on that gen bike but anyways, I've been looking over the wiring diagram in the shop manual... The neutral light working tells me the ground for the dash is viable, or it's grounding through something else as all the indicator lights and the dash itself use a common'd ground, black with white stripes. That line goes almost to the ECU where the diagram shows it bridged with a solid black wire and ground. I see two hots going to the dash, one is constant (Clock, etc?), one is ignition key switched. I also see two yellow wires out of the dash to the ECU with no other connections that I'm guessing are a data bus between the two? Current theory is a ground issue, anyone got any other suggestions on things to examine?
Welding current broke the dash? Dash is just bad? If it’s getting 12v and it doesn’t work, replace it.
The wrench is a idiot. There is no computer diag for that gen. Only dealer mode where you can pull codes.
It's Diag Mode. Not a secret. Same as most (if not all) F.I. Yamahas pre '17. And yes, it's all through the meter. No special Yamaha computer needed. If you/he did everything you said, you need to start checking all wires going in and out of the meter (voltage).
Will the dash power up without communication to the ECU? My first thought is to verify both dashes show some signs of life if given 12v without being on the full harness?
