Trouble with Airbag warning lights on a Fiat Ducato

[jezport]

Personally I don't think it's a voltage thing.
Possibly a damp issue due to condensation.

 

[SpeedyDux]

I am having similar problems. First was a faulty battery causing low voltage and B0100-49 fault.
Crashdata repaired the ecu. I fitted a new battery, charged it over several days and then fitted the ecu. All good for a few days until I started the van on a cold morning. B0100-49 fault again.
This time, Crashdata say the fault is permanent and a new ecu is required (reconditioned - i.e. old unit reprogrammed to my van!) @ about £360. They believe that the hard start-up was the cause. If so that is a piss poor design from Fiat.
The lady also told me that over the past year, crashdata repairs to airbag ecu's are to a majority of campervans/motorhomes that are just sitting around. She also said that they rarely get any commercial van failures as they are in constant use.
To me that would imply faulty trickle charging of the started battery.
Sure enough, the Shauldt was only charging at 12.8v !
More expence.....

I agree 1000%. It's a scandal.

These are very easy to fit and log voltages with cranking test too.. £25

<Broken link removed>

That's a way to corroborate the printout you would get from Crashdata. Not sure how that gadget really helps prevent a low voltage event from happening. I am a gadgetaholic but this one's not for me.

 

[MR. FUSION]

Personally I don't think it's a voltage thing.
Possibly a damp issue due to condensation.

It's possible, I think nobody at FIAT really considered in the design of the cab that it would often be swimming with condensation from bodies spending the night in there.....

 

[Richard n Ann]

It's possible, I think nobody at FIAT really considered in the design of the cab that it would often be swimming with condensation from bodies spending the night in there.....

Maybe they didn't think about motorhome use but you'd be surprised at what the electronics manufacturers put their circuit boards through during testing, I can only speak for Pektron in Derby but it's typically 80°c for 30 min then -80°c for 30 min continuous all logged for a period of 3 months and the board has to work flawlessly. Then there's a vibration table that looks quite horrendous but I never saw that working, a dust chamber that uses Japanese volcanic dust and a radio interference chamber test. Forgot the name for that, Lenny or autorouter will know.

I used to work on the thermal shock chamber.

 

[cookie]

I dont know if this has been asked before, but are there particular brands of motorhomes that are more susceptible to this fault.?

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[Alan Atkin]

They could be susceptible to transient high voltage pulses just after the starter motor stops, the processor throws up a fault code but doesn't record the peak voltage... Just a guess, poor design whatever it is.

had the same fault on my peugeot was not a member here then did not know anything peugeot charged £560 and wanted to keep the unit. I retrived the unit looked on the internet identical one from bosch £75. The mechanic did say that they had fitted an extra earth wire as recommended by the big 3 engine groups should have joined this site years ago
have a nice day

 

[MR. FUSION]

Maybe they didn't think about motorhome use but you'd be surprised at what the electronics manufacturers put their circuit boards through during testing, I can only speak for Pektron in Derby but it's typically 80°c for 30 min then -80°c for 30 min continuous all logged for a period of 3 months and the board has to work flawlessly. Then there's a vibration table that looks quite horrendous but I never saw that working, a dust chamber that uses Japanese volcanic dust and a radio interference chamber test. Forgot the name for that, Lenny or autorouter will know.

I used to work on the thermal shock chamber.

That's very interesting thank you, I did visit Lucas years ago & remember seeing them test banks of dashboards to the 9 (?) hour concept, that bad electronics often fail in that timescale?

 

[PeterE1947]

Mr.Fusion,Jezport are saying the same as my Peugeot dealer that its caused by condensation from sleeping bodies. They said that they haven't replaced the airbag ecu in any vans only "motorhomes".Ours also failed after a short lay-up. However,I use a dehumidifier and get about .5 ltr each day unless there has been a frost then there is no water in the reservoir.If it is caused by damp then surely they are responsible to provide an electronic device suitably sealed against damp from whatever cause. I have contacted Peugeot about our failed airbag ecu. At this moment the dealer is sourcing a replacement (over a week ago now).We are hoping Peugeot will pay for a replacement or at the very least a hefty contrabution.

 

[Jean CrashData]

With apologies if this is a bit of a thread hijack, but, after five relatively trouble-free years owning our 2012 Peugeot Boxer-based Autoquest 180, we have recently joined this unhappy and apparently growing club of airbag ECU fault victims

A similar story to many others... Airbag failure light came on suddenly when starting the motorhome one day before Christmas and remained on, despite attempting to clear it by driving the vehicle and doing a controlled reboot of the main system (e.g. http://www.petercoopercarrepairs.co.uk/peugeot_bsi_reboot_procedure.htm). I enlisted the help of a mobile sparks whose two professional scanners (one £1000 unit and a Snap On unit costing several grand) each of which revealed the dreaded 'B0100-49 Error inside the control unit' code and no others errors.

Sent the airbag ECU off for repair and have now received it back with "before" and "after" reports, which appear to be printouts from the FIat Multiecuscan software. See attached photos - the report with the yellow-highlighted text is the report before they repaired and re-tested the airbag ECU.

There are a couple of things in these reports which I'm not sure about and which I'd appreciate Funsters' advice on, especially from Riverbankannie, Christy, Nigel Crompton and others who have been down this road:

1. The odometer readings recorded against the errors in the reports appears to be many thousands of miles different to my current odometer reading.
The Airbag failure warning and light appeared for the first time ever the week before Christmas (i.e. December 2021), at which point the odometer would have been reading at least 26,202 miles. (I'd successfully MOT'd the van days previously and this was the recorded mileage.)

However, the reports I've received from the repair company give odometer readings of just under 17,000 miles for B0100-49 and the other errors! Based on mileage recorded in previous MOTs and my subsequent usage, my odometer would have last have been at 17,000 miles back in Spring 2019! Has anyone else spotted a similar discrepancy in reports they have received or is it likely that I've possibly received someone else's reports in error?!

2. The post-repair report still shows six other errors:

• U1703-07 Communication with Instrument Cluster (IPC/NQS)
• B0106-1B Driver's pretensioner resistance
• B0107-1B Passenger pretensioner resistance
• B0104-1B Passenger airbag resistance (1st stage)
• B0103-1B Driver airbag resistance (1st stage)
• B0127-13 Driver's seat belt switch

Have other Funsters also seen similar errors on their post-repair reports? If so, did the faults disappear when you reinstalled the Airbag ECU or did they have to be cleared using a suitable SRS-capable OBD2 tool?

Like some others in these forums, I was really surprised to see the root cause attributed to low voltage with the advice to get my battery checked. I replaced the original vehicle battery in January 2020 and fitted a new leisure battery and MPPT solar controller (with logging) last year. I have a Battery Master and am in the habit of checking the voltage of both batteries at least once a month and regularly downloading the logs from the solar controller, with no issues at all.

One possible cause that did occur to me was that I replaced the casing of my nearside wing mirror immediately before the airbag failure appeared. Perhaps unwisely, I did not disconnect the vehicle battery before unplugging and removing the heated mirror glasses, so I guess some sort of short may have occurred - not that the ignition was on at that point. The auto electrician dismissed this as a possible cause of the airbag fault, but I thought I'd just mention it in passing...

I'm obviously going to follow up the above queries with the repair firm, but would appreciate any advice Funsters can give on the above so that I am armed with as much info as possible.

Sorry for the lengthy post but thanks for reading!

Cheers,

Jez

Hi Jeremy,

This is Jean (CrashData.co.uk) here, (the company that has just reset your module). I just wanted to answer some of your queries on here as this may help others that are having similar problems to you.

1. Post-Repair Errors
As per our telephone conversation, the reason you have those 6 fault codes on your post-repair test report is because we test the module after repair and we disconnect all external bags and sensors to check that the module is in fact looking for those belts and sensors and functioning as it should.

2. Odometer Differences
Now, onto your mileage, or should we say your kilometers recorded on your dash. The reason there is a discrepancy from the test report to your dash is due to the fact that you are not recording miles, you are recording kilometers. The 26202 km on your dash =16281.2 miles when converted. I believe your test report shows 16287.4, which is an actual discrepancy of 0.04%. This is no coincidence.
We have seen this a couple of times over the years, so don't worry, you aren't the first person to be confused by this.
The bigger issue here is that you think have been recording in miles, (logged on your MOT) when in actual fact your vehicle has done almost 10000 miles less than you thought!!

Finally, you don't need to come to us armed, we are very approachable and we do want to help.

 

[Greenie]

I used Northern AutoTech (07870903552). Their man, Carl Bulger, charged me £55.00 to reset my ECU that had fault code B0102.

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I posted it off on a Thursday afternoon and it was returned the following Tuesday. My local garage then plugged it into a PC and proxi flashed it. Three weeks later it passed the MoT and the light is still off.
Usual caveat. I'm just a very satisfied customer.

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[Greenie]

Oops - wrong button! I should have typed "Three weeks later it passed the MoT and the light is still on"
Just can't get the staff these days, can you?

 

[huck999]

Just an update on my experience:
Due to not using the van much lately (last 2 years!), the starter battery was a bit ify, mainly due to me thinking the Schaudt charges it whilst on mains (it does not, due to fiats weird electronics) It, however, seemed to recharge ok. Unfortunately, it set up a B0100/49 fault which CrashData cleared. I made sure that the battery was topped up before fitting the repaired ecu. All good for about a week but when I started the van, it struggled as the battery was, in fact, shot and not providing the required amps.
The ecu module was now terminal.
A new one was supplied by CrashData, a new battery installed and charged, and the ecu fitted.

So far all is good but I definitely think this supports the idea that bad batteries are the main culprit. Vans in constant use - e.g. couriers - do not generally have ecu problems, according to CrashData.
There is also good evidence for moisture getting into the module when fitted on the floor as in ducatos. Maybe some waterproofing spray to help out?
Another tip it to fit a cable from a screw on the ecu case to the earth point near the battery. Not sure what this does but cant hurt to add one.
Total cost of this exersize: £80 initial reset. £380 new module. £180 battery, and for good measure...
...I have now purchased a Battery Master from Jim to keep the starter battery in tip-top condition whilst we are parked up. £70.

Big thanks the Jean and CrashData - here's hoping I never need you again

On a better note - we are off to europe, via Newhaven, for our 90 days Schengen allowance. YAaaaa!