I All,
Just sharing a little knowledge after working on a FZ6 where engine turns over but immobilizer won't turn off and hi temp reading on speedo.
After many hours scratching my head realised it could be a broken wire or circuit. I traced black/white wires to a small connector where 4 bk/w wires go in. Its taped onto loom near ECU. As soon as I moved it fuel pump primed! I took top off and it has a connector bar which pulls out and was corroded. Cleaned it up and hey presto, fixed.
Hope this info is useful and will save a fortune paying for mechanics to scratch heads and charge you for the privilege!
Steve.