Ducato, Comfortmatic, Cheack Gearbox & Immobiliser lights on.

[UK-Kiwi]

2009, 3litre, comfortmatic, 40H chassis, Rapido motorhome. Been driving for about 10 miles, slowing for roundabout and engine stopped. "Check gearbox" light flashing and message on dash. Immobilizer light on constantly, engine turning over but will not start. OBD2 port cannot connect to ECU so no codes available. Recovery firm could not read with their scanners either. Have removed and cleaned all fuses and relays, new 110ah battery fitted and new earth leads. Checked "rusty junction" connections and looms, no faults found. Checked brake light switch. Same errors still on dashboard.

 

 

Only other thing, I was towing a Chevy Spark on an A frame, have towed it over 1k miles without problem.

 

 

Any ideas, suggestions gratefully accepted.

 

 

Thanks.

[euroserv]

Hello,

 

Brief story first, and hopefully you will see why....

 

We had a 2011 van that had a coolant issue which eventually showed itself as a leaking heater matrix. We removed the dash and fitted an new one plus radiator and fans but when we went to fire it up we only had an immobiliser light on and it would not start. We could also not get in to the ECU at all. The assumption was made, although we were completely sure that we had not forgotten to connect anything and that we had not trapped any wiring, that we had to take the dash back out and check it all. Nothing. We started tracing wires from the body computer and tried to find a lost signal somewhere in the loom and found nothing. We put it all back together with the same result. Immobiliser light and not starting.

We eventually removed the nearside headlamp and started to examine the wiring in the area and stumbled upon an broken wire in the loom between the ECU and the bulkhead where the loom goes into the cab. Fixed that and all was well again.

 

The moral of the story is that there was a broken wire for the immobiliser connection from the body computer to the main ECU which serves as a 'wake-up' signal. Without this nothing works!

The Ducato wiring is at best al-dente spaghetti and is a pain but being methodical; faults can be located. In our case, the fault was completely unrelated to the work that we had been doing and unfortunately this sometimes happens.

 

The fact that you had a gearbox fault come up at the same time is probably a red herring since various systems will justifiably get upset if the engine suddenly stops. I think that if your garage can find the immobiliser fault (which is probably similar in nature to the one we had) this will be all there is and the gearbox etc will be fine.

 

Keep us posted though....

 

Nick

[UK-Kiwi]

Thanks Nick, I thought you would have some ideas. ;-)

I have had all, well all I could see, connectors apart and cleaned them but have not started undoing the looms. Long time since I had to do that, Mk1 Mini, but I had nothing else planned this week! Like you, I think the gearbox light is erroneous, did it a couple of years ago, but Italian wiring is something else, so speaks an ex-Lancia mechanic ;-)

Thanks again

Regards

Simon.

[UK-Kiwi]

Update on Friday :'(

Called the auto-electrian in on Wednesday and he got the fiat wiring diagrams up and used his electronic wizardry to check various circuits, fuses and relays. Confirmed that there was no link between ECU and anywhere else but could not find a broken circuit. Decided to check ECU and took to his workshop. Confirmed today that all looked good, no moisture or obvious signs of damage so sent it to a specialist who has checked it and confirmed that it is completely dead. He cannot get anything out of it at all. They're recommending taking the van to Fiat Commercial for replacements, that should be inexpensive. Won't get ECU back until Monday and will get a more in depth report then, hey-ho.

Will keep you posted.

[UK-Kiwi]

Update at last!

 

After getting ECU back I took it to another auto-electrian who could read it! Next move was to get MH to him so he could test all the wiring etc.

 

After several abortive attempts to transport the MH to the electrician's place, I eventually got it there a couple of weeks ago. After checking the wiring and other electrical bits the ECU was sent to Bosch in Germany for inspection. They found it was a component failure but as it is a multilayer processor it was irreparable ??. No definite reason for failure found, could have been an electronic spike or just "old age", just unlucky I guess. They supplied a replacement with full Bosch warranty and all running fine now.

 

Many thanks to Ryan at 'Sparks & Sensors' in Kirkham for his patience, knowledge and skills for sorting it out at a very reasonable cost (less than half of Fiat's estimate).