Technical 2015 Ducato X250 Euro 5 Airbag and fuse dilemma

[the green vanper]

Thanks for taking the time to post this document, although I attached the whole document as an attachment earlier in the thread. The ECU is dated 2023, so it was replaced and not reset. I didn't manage to clear any codes as the body computer won't talk to the Airbag ECU. I did the proxi align which then basically thought there was not an airbag system fitted at all!

Agree with your "I'd disconnect the battery following the procedure from the owners' manual (which prevents damaging the airbag module!), then try to discharge any residual voltage from the system and yourself and then disconnect the module, which will allow you to check if there's continuity between the plug and the F50 fuse." comment.

I've already made an additional earth which didn't help with this error.

Mondays job!!

True, I have not checked the contents of what you've posted, looking at the title I assumed it's only the wiring part. Sorry.

Two more thoughts:

what is the interface you're using to connect to the OBD port? I have no idea if the has an impact on the BCM / airbag module connection, but normally the airbag module requires an OBD cable + the yellow adapter to connect to the airbag module. Alternatively the bluetooth adapter can be used.

Isn't the airbag module from 2023 too new? I know FIAT messed up again with the electronics / equipment (possibly also with compatibility) in 2021... Who did the module replacement? You wrote that it was 550 GBP. Have you got an invoice? I'd check with them first, especially you've said it was before you've bought the camper 5 months ago. Was the odometer blinking since the purchase? Or it just happened recently?

Have you played with seats? Or with the starter battery?

 

[growlybear]

True, I have not checked the contents of what you've posted, looking at the title I assumed it's only the wiring part. Sorry.

Two more thoughts:

what is the interface you're using to connect to the OBD port? I have no idea if the has an impact on the BCM / airbag module connection, but normally the airbag module requires an OBD cable + the yellow adapter to connect to the airbag module. Alternatively the bluetooth adapter can be used.

Isn't the airbag module from 2023 too new? I know FIAT messed up again with the electronics / equipment (possibly also with compatibility) in 2021... Who did the module replacement? You wrote that it was 550 GBP. Have you got an invoice? I'd check with them first, especially you've said it was before you've bought the camper 5 months ago. Was the odometer blinking since the purchase? Or it just happened recently?

Have you played with seats? Or with the starter battery?

Its Gendan kit with the yellow interface cable.
The module has a manufactured date of 2023, and was working fine with no faults shown since I bought the camper 5 months ago. The Airbag ECU was from Crashdata but fitted by a Fiat Professional dealer close to the previous owner. The odometer didn't blink until the error was displayed on the dash.

Now the seats do swivel, and I read today that if the pretensioner wires are shorted it can cause the airbag ECU to be unrepairable. I need to look further into this. It may be factually incorrect...

 

[the green vanper]

Now the seats do swivel, and I read today that if the pretensioner wires are shorted it can cause the airbag ECU to be unrepairable. I need to look further into this. It may be factually incorrect...

Yes, so that's the most probable cause of the error. Even disconnecting the pretensioner cables under voltage can damage the module. There's a thread on the forum listing a company in the UK that repair those modules. Didn't bother to memorize the name as it's too far away for me anyway

 

[growlybear]

Yes, so that's the most probable cause of the error. Even disconnecting the pretensioner cables under voltage can damage the module. There's a thread on the forum listing a company in the UK that repair those modules. Didn't bother to memorize the name as it's too far away for me anyway

Indeed almost 2000 miles!

I've seen 2 companies Crashdata and Northernautotech. I've heard many mixed views of the former.

If when I check I can see +12v and an earth on the airbag ecu, and the after checking the pretensioner wires are ok, I'll buy a new ecu.

 

[the green vanper]

I've even read threads that discharging the starter battery (with no leisure battery connected) to a low voltage (can't remember the value) caused the airbag module error to appear. They are very sensitive. And that's understandable.

I had something stealing the voltage from my starter battery (I assume it's the trailer hook CAN module, which is constantly under voltage and 2 LEDs blinking, don't ask me why) and had the battery voltage to drop dramatically low (to something like 2 - 3 V only) twice during summer last year, but luckily the airbag module does not show any errors. Perhaps due to the fact that the van was left parked for a longer period of time, and when I've discovered the battery was dead I've recharged it before turning the ignition on. It's a guess of course...

FYI, during the pandemics (probably until 2022) buying the airbag module for the x250 was impossible. They were not available at all.

 

[growlybear]

UPDATE Fixed!!
So the wiring diagram showed F50, and my F50 was missing.
I thought it might have been rewired in the past and that's why there wasn't a fuse present.
Battery off, and checked the airbag ECU earth at pin 1 of the grey connector - all ok. Checked continuity between pin 2 grey connector and F50 - all good.
Battery back on, and checked 12v at pin 2 (ignition on) no 12v. Fitted 7.5A fuse and now 12v, showing that there was no alternative source of 12v (ignition on).
Battery back off, everything put back together.
Ran Mes DTC, and showing an airbag now connected.
Cleared all codes and did a proxi align.

Airbag lighting up as expected, as is the seatbelt light.
Can connect to airbag ecu directly and read off parameters.

Now, what happened to the fuse? I have no idea how/where it fell out... When I come to fit my lithium leisure batteries I'll be able to look better.
For now, a happy chappy. Let's hope I've not jinxed it by posting too soon...

 

[the green vanper]

Great news!!!

About the fuse: perhaps the person installing the new airbag module took it out to be sure not to damage it and forgot to replace it afterwards?

 

[growlybear]

Great news!!!

About the fuse: perhaps the person installing the new airbag module took it out to be sure not to damage it and forgot to replace it afterwards?

I actually wondered the same, and that perhaps the dealer removed it to isolate the airbag ecu rather than disconnecting solar, leisure and starter batteries, and of course switching of the EBL switch block, and when refitting, it wasn't pushed fully home. If I can't find it, then goodness knows! Time will tell if it fails again in the near future.