Yamaha YP125 Majesty

By Andy

 Today we figured out how to decode the flashing engine warning light.

It's a bit like morse code, where a dash represents 10 and dot represents 1 - we saw two errors

- - - = 10+10+10 = 30 

- . . = 10 + 1 + 1 = 12


Code 30 appears to be the tilt sensor - this was fixed by re-fitting it the correct way up.

Code 12 appears to be crank position sensor - same as it ever was.


Despite reaching out to forums and Yamaha, we've not had much luck figureing this out.  We measured about 1.2V ac at the ECU on the sensor wires when the engine is cranked on the starter.  Still no spark though.  We also buzzed out the wires from the ECU to the coil.

Originally, only the old ECU was giving the code 12, but now the new one does too.

We haven't managed to find a diagnostic port to plug in to yet.

We're thinking of putting the pieces together for now, to keep all the bits safe, while we try to get more information.