999S won't start - error 37.3?
 

My 999S has steadily developed a temperamental starting issue which is getting worse. The battery is good the bike turns on but when I hit the starter button their is a click, a slight movement on the clutch, a flash of the engine management ligt and nothing more. Every press of the starter gets the same response.

If I leave it a while on the optimate the bike might do the same or it may fire into life. Although it's firing less and less now as though something is loose.

I have checked the code 37.3 which is immobiliser serial cable disconnected. My question is what / where is the immobiliser serial cable???

I've checked all my connectors, the ecu, I've added another earth from the battery and I'm out of ideas as to where to go now. It did start this evening but when I tried again seconds after turning it off failed to start with the above symptoms. Lights all work, dash works.... I'm at a loss!!

It's the aerial part that runs up to the ignition lock and should go round the lock right at the top of the ignition lock cover.

What normally happens is that the ring of the aerial dislodges inside the cover and drops down, so it is unable to read the code from the key.

Take the two dome-nuts off and check under the cover. If it's still in place, check the aerial ring as it may have got water in and they start to corrode inside. Replace it and it should be fine.

Cheers Ant I've had a look at the ring and ordered a spare to make sure it's not that. I've been at it a few hours now and cleaning all the contacts. It has fired up once this morning but when I shut it off it instantly went back to refusing to start.

Runs fine when it starts... Really got me scratching my head!

Whenever there are electrical gremlins with my 999 the first thing I change is the injector/coil/pump relay. It's found on the back of the battery box, behind the heat shield and below the starter relay. You need a 12v 4 pin micro relay.

Well after an eventful 2 days in the garage trying to trace the fault it appears I have a dead cell in my battery. The battery reads a good 13.05 volts but as soon as it's off the trickle charger the volts drop one by one. The bike started without the atenna ring attached which leads me to believe the immobiliser has been bypasses somehow and the 37.3 code is telling me the immobiliser is off in effect.

Got my new antenna on this morning but sadly the bike didn't start

Anyway after a conversation with Ducati John, a new battery and a couple of 12v 4 pin new relays (as my DUCATI was using MG ROVER 5 pin relays!) and she's fired up without hesitation.

Just to confirm the battery was changed first and the bike worked. The relays were swapped out after, not that they are faulty however... Well they say MG ROVER on them so it's only a matter of time before they melt!

Thanks for all the help guys!

Glad it's sorted. I'll add dead cells to my list of fault causes.

Wow, red herring with the immobiliser code!
Always good to change the relays. The 4 pin and 5 pin are the same unit internally but the extra pin allows you to have both ON and OFF wired rather than just ON.