Engine doesn't start!

Hi everyone,
I put down the engine of my B11 to fix an oil leak (and some other mechanical works).

Reassembled everything again and the engine doesn't start!

I get dashboard errors:
DSB01 key code read but not recognised
DSB04 internal controller fault
DSB07 Oil sensor fault

Turning the key I can hear the fuel pump.
Pressing the star button there's the typical "tack" sound from the starter motor (?) but the engine won't start.
Right after the "tack" I hear the fuel pump again.

Any clue?!!!

Sounds most like a poor connection at the battery or the main earth.

If the key was not being recognised you wouldn't get to the start point. The dash would simply ask you to insert your personal code before allowing anything at all to happen.

Typically if the battery connections or ground are bad as soon as you hit the starter button the resistance at these points causes such a collage drop that the ECU recognises low voltage and kills everything stone dead. Once the button is released the voltage climbs and everything starts up again. It could also be a dying battery but if it was working before and the battery wasn't left unattended and unloved for a long time I'd still say a dirty/loose/corroded connector would be the most likely culprit.

Pete

Well Pete, the battery is 9 months old. It has stayed with the + pole disconnected for about a month, the time I was working on the bike.
An bad connection would be a comforting scenario. I will check and clean all connections and sockets and see what happens...

Don't want to add confusion to the conversation BUT, the day before I was getting service light on dashboard. Connected to Guzzidiag I got ECU faults P0115, P0110, P0120, all of them "too high" and finally P0505 "no signal". Like most of the sensors where gone.
The next morning no service light and faults gone... Go figure

Pete you nailed it!
Low battery voltage and bad contacts was the reason for all this shit.
Fixed that, the bike came alive again!
Thanxxxx