Fiat ducato air bag warning light is on…..AGAIN.

Camper634

Camper634

Joined
Dec 18, 2011
Posts
775
Likes collected
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Location
Hull
Funster No
19,200
MH
Autotrail 634
Exp
Since 2006
For the 3rd time in less than 12 months the air bag warning light is back on the dash.The last time was 6 weeks ago when it cost me £88 with crashdata to have the module reprogrammed.I did ask the question then why has it gone again.One of the replies it could be high voltage when starting the engine.So every time since the last replacement i have turned the ignition to on and waited until the various lights went off before cranking the engine.This morning i only tuned the ignition on to check mu LPG levels and almost immediately the air bag light came on.
I am at a loss what to do next.I cant keep paying £88 God knows how many times.Has anyone please got/had this problem and found out a reliable fix?Any help greatly appreciated.
 
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If I haven't driven the van for a few days I always use EHU to charge the batteries fully before starting it. Today for example the (new-ish) starter battery voltage was 12.6v so not fully charged. I feel sure that when I had this problem about 2 years ago, it was caused by the van not having been driven for 10 days, plus a 4 year old starter battery causing a big voltage drop when turning over the engine. Even though it seemed to start the engine easily.

Definitely a FIAT design defect. I am surprised that DVSA haven't forced a Safety Recall because a defective airbag ECU module may cause the airbags and seatbelt tighteners not to deploy in a crash. Or, if driving solo, might cause the wrong airbag to deploy.
 
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I bet The Fiat Proff Garages, plus MH dealers with workshops, have got a draw full of replacement Airbag Sensors, ready & waiting for the next van they service to show a failed unit!
This problem cannot be allowed to continue for so many years plus into the future, before Fiat are forced to address it.

How can we force Fiat to recognise there is a problem? Why haven't MH dealers, Fiat Garages, any watch dog out there not managed to get some resolve thus far.
Replacing FOC under 2 year warranty for a known fault is simple not good enough.:mad: They are Timebombs, they can fail at any moment! defective units must be dangerous, as the van will fail an MOT with just the warning light showing on the dash!
EDIT: SpeedyDux has just answered part of my question(y), why hasnt the DVSA forced Fiat to solve this known problem across so many vans over many years?
LES
 
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We could start by making sure never to buy another Fiat but that would rule out 80% of motorhomes.Dealers aren't interested once you hand over your cash and drive away.If this was in the car industry there would be hell on.

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My 2014 Rapido lasted until 2020 and went while standing during covid lockdown. I can probably understand why low voltage is flagged up as it could affect airbag deployment. What I can't accept is that the fault does not reset with a fully charged battery or that it can't be reset with an OBD2 reader. The cost of renewing the ECU from fiat is exhorbitant, hence why these fixit firms have sprung up. Thank you Crashdata.
 
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Camper634 said:
No i wish i was😂I should have added that it bleeped aswell as soon as i turned the key and i knew……here we go again🤬🤬
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Driventemple said:
After two failures I fitted a NOCO Genius1 permanently plugged to the vehicle battery. When in the drive at home the mains lead is always connected, with the charger only switched when the solar panel can't cope in winter.
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TinaL said:
Hi Driventemple I looked up a NOCO Genius 1, I see its a 1 amp mains charger that can charge all types of batteries preferably keeping them maintained while not in use.(y)
If you fitted a Vanbitz Battery Master, just 3 wires between Hab & Cab batteries then any surplus charge from the leisure bats would be sent to the cab battery,@1amp, keeping that topped up for free if you have sufficient solar.

Sorry if you already new about Battery Masters, but it does save hooking up a separate charger in the winter months, and saves on the lecky bill.(y)
LES
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SpeedyDux said:
If I haven't driven the van for a few days I always use EHU to charge the batteries fully before starting it. Today for example the (new-ish) starter battery voltage was 12.6v so not fully charged. I feel sure that when I had this problem about 2 years ago, it was caused by the van not having been driven for 10 days, plus a 4 year old starter battery causing a big voltage drop when turning over the engine. Even though it seemed to start the engine easily.

Definitely a FIAT design defect. I am surprised that DVSA haven't forced a Safety Recall because a defective airbag ECU module may cause the airbags and seatbelt tighteners not to deploy in a crash. Or, if driving solo, might cause the wrong airbag to deploy.
Click to expand...
Charging the battery and keeping it topped up doesn’t help the OP, who like me, had the fault caused/ diagnosed as “high battery voltage” 14.6 in my case.
I too always pause, turning the key and then sorting out seatbelt etc before starting but this method doesn’t seem to have worked in this instance.
 
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To add to the reasons for failure my ecu failed a few months ago with a code indicating an internal earthing fault in the air bag ecu.
Had it repaired and changed the earth straps on the engine , gearbox added one to the cab battery and ensured there was good earth between the ecu body and chassis.
Will that help!
Time I guess will tell
 
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Are all these vans with failures RHD? Any with LHD - although I suspect yours is Lenny HB. Don’t see why it should make any difference though.
Is it anything to do with MH conversions having passenger airbags fitted whereas working vans may not?
Clutching at straws 🤣
 
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Riverbankannie said:
Are all these vans with failures RHD? Any with LHD - although I suspect yours is Lenny HB. Don’t see why it should make any difference though.
Is it anything to do with MH conversions having passenger airbags fitted whereas working vans may not?
Clutching at straws 🤣
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Mine is a self converted builders van, so I doubt it.

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Riverbankannie said:
Charging the battery and keeping it topped up doesn’t help the OP, who like me, had the fault caused/ diagnosed as “high battery voltage” 14.6 in my case.
I too always pause, turning the key and then sorting out seatbelt etc before starting but this method doesn’t seem to have worked in this instance.
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My crashdata error code printout said 14.4v. That error might be an error too, because B0100 can be either too high or too low voltage. When the old starter battery has been sitting unused for 10 days and depleted by parasitic discharge (e.g. the cab radio on standby) the low voltage cause seems the more likely of the two. Especially when you see the starter battery dip to 9v momentarily when it cranks the engine.

Riverbankannie said:
Are all these vans with failures RHD? Any with LHD - although I suspect yours is Lenny HB. Don’t see why it should make any difference though.
Is it anything to do with MH conversions having passenger airbags fitted whereas working vans may not?
Clutching at straws 🤣
Click to expand...

To answer your question, the French forum CAMPINGCAR-INFOS has similar threads:

 
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SpeedyDux said:
My crashdata error code printout said 14.4v.
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Well mine was VERY high voltage :whistle2: :laughing:
157D2ECF-99E5-4555-96D3-EA1832C27C85.jpeg
 
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Lenny HB said:
Had mine reset by crash data two weeks ago, put it back in all OK then on Thursday checking the van out before mot on Friday flipping light is back with the same error code. Was supossed to be on a ferry tomorrow.
Sent it back to Crash Data yesterday but postal strike so they won't get it until Monday. All ready put our trip back two weeks because of when it first went wrong.
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Have you ever figured out how and what Crash Data do fix them?
Do they replace components or simply flash new software to it?
 
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Stealaway said:
Have you ever figured out how and what Crash Data do fix them?
Do they replace components or simply flash new software to it?
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Believe they use multiecuscan to clear the error codes and reset the ECU.

edit: fixed the name:doh:
 
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Gellyneck said:
Believe they use MultiVue to clear the error codes and reset the ECU.
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I assumed it was the same family as Multicuscan as the Report printout is very similar.

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Gellyneck said:
Believe they use multiecuscan to clear the error codes and reset the ECU.

edit: fixed the name:doh:
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The garages I've had test ECU have only ever said it was the airbag module and had to be replaced.
I'm sure Crash Data have different software
 
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Stealaway said:
The garages I've had test ECU have only ever said it was the airbag module and had to be replaced.
I'm sure Crash Data have different software
Click to expand...
This is the bottom of the report I received from them.
1664808759066.png
 
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TinaL said:
This problem cannot be allowed to continue for so many years plus into the future, before Fiat are forced to address it.
Click to expand...
The short injector wiring has been going on 20+ years on Fiat;Peugeot,Citroën. & no recall?
 
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A chum of mine (electronics and software background) based on reading the thread and a guess that "White van man" does not suffer from this issue has concluded that the high voltage issue has to do with the solar panel output voltage appearing across the battery as the ignition system is engaged. He too has had this issue and is sending his ecu off for repair. He also had a related issue that caused his electrics to switch off at periods during daylight hours. Thankfully the Sergeant people pointed to the problem, the solar panels.

This morning he fitted two isolation switches to the solar panels with a view to turning them off before he starts the van in future.

He'll keep me posted as to fault recurrance and I'll let you know if it does.

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Dramfineday said:
A chum of mine (electronics and software background) based on reading the thread and a guess that "White van man" does not suffer from this issue has concluded that the high voltage issue has to do with the solar panel output voltage appearing across the battery as the ignition system is engaged. He too has had this issue and is sending his ecu off for repair. He also had a related issue that caused his electrics to switch off at periods during daylight hours. Thankfully the Sergeant people pointed to the problem, the solar panels.

This morning he fitted two isolation switches to the solar panels with a view to turning them off before he starts the van in future.

He'll keep me posted as to fault recurrance and I'll let you know if it does.
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So my solar charge goes through a Vanbitz battery master which states regulated at 1.1amp and boosts the vehicle battery from the leisure battery. Would this be a big extra voltage?

Our specially designed, fully waterproof, resin bonded product will monitor the engine and the leisure batteries constantly and whenever the engine battery needs a ‘boost’, Battery Master allows a safe and regulated controlled charge.

Built-in automatic regulation and fusing ensures a safe and efficient 1.1 amp ‘trickle charge’ making it totally safe for all electrical components and any motorcaravan. Have this British Made product fitted to your motorhome and forget the battery blues.
 
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Riverbankannie said:
So my solar charge goes through a Vanbitz battery master which states regulated at 1.1amp and boosts the vehicle battery from the leisure battery. Would this be a big extra voltage?

Our specially designed, fully waterproof, resin bonded product will monitor the engine and the leisure batteries constantly and whenever the engine battery needs a ‘boost’, Battery Master allows a safe and regulated controlled charge.

Built-in automatic regulation and fusing ensures a safe and efficient 1.1 amp ‘trickle charge’ making it totally safe for all electrical components and any motorcaravan. Have this British Made product fitted to your motorhome and forget the battery blues.
Click to expand...
As I understood the battery master it only activated charge to the starter battery if the starter battery volts dropped to 12.5v
IF” I am correct then I don’t think the battery master is likely to cause a problem.
 
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Dramfineday said:
A chum of mine (electronics and software background) based on reading the thread and a guess that "White van man" does not suffer from this issue has concluded that the high voltage issue has to do with the solar panel output voltage appearing across the battery as the ignition system is engaged. He too has had this issue and is sending his ecu off for repair. He also had a related issue that caused his electrics to switch off at periods during daylight hours. Thankfully the Sergeant people pointed to the problem, the solar panels.

This morning he fitted two isolation switches to the solar panels with a view to turning them off before he starts the van in future.

He'll keep me posted as to fault recurrance and I'll let you know if it does.
Click to expand...

Riverbankannie said:
So my solar charge goes through a Vanbitz battery master which states regulated at 1.1amp and boosts the vehicle battery from the leisure battery. Would this be a big extra voltage?
Click to expand...
I don't see either of those being a problem. The voltage from the solar is not going to be any higher than what the alternator puts out and in most cases lower.
 
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Riverbankannie said:
Are all these vans with failures RHD? Any with LHD - although I suspect yours is Lenny HB. Don’t see why it should make any difference though.
Is it anything to do with MH conversions having passenger airbags fitted whereas working vans may not?
Clutching at straws 🤣
Click to expand...
Mine is LHD and plenty of reports on the Fiat forum and they are from different countries.
Riverbankannie said:
Well mine was VERY high voltage :whistle2: :laughing:View attachment 672510
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I wouldn't class that as high Alternators charge at 14.2 - 14.5v and the new smart ones up to 15v.
 
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We are on our 3rd Ducato since 2008 and this is the first time we have had a problem, all vans have had solar.

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My 2014 Rapido also went in October last year just before the MOT was due - new replacement in January (I did email Fiat but where they bothered?? 😡) - no solar so that wasn’t a cause - like others, I suspect it being more laid up during lockdown may have caused a lower power battery, but again like others, this shouldn’t be a reason for failure. There should be a Europe wide poll of Fiat Ducato based motorhome owners and get the motoring/mainstream press involved (Fiat Professional prices to rectify are not cheap) - interestingly though, does anyone know if the similar Peugeot/Citroen vans suffer with the same design issue?
 
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Now bear with me as I explain a little background info. If we want to run something sensitive to the supply voltage in the van, we fit a device between supply and device. This is called a buck/boost voltage stabiliser circuit. I use them for running the 12v router and protecting from under or over voltage.

This device takes the incoming voltage and the circuit either amplifies the voltage whilst lowering the current of the output or detects over voltage and cuts it off at the precisely set required output. If you use a good one, it will detect and block voltage spikes and cut these off too. All for a minimal power drain on the supplying system.

Now reduce the airbag circuit and it's ecu to a diagram and you will see that some, but not all of the components rely on a voltage change to detect a fault in the circuit or worse a possible impact, so compares the reference voltage being supplied with the "fault/alarm". If the incoming positive feed to the ECU is corroded or significantly under or over voltage the memory on the ecu can get corrupted. Hence reflashing the code fixes most faulty ecu's

Back to the buck/boost circuit. Why can't we fit a buck/boost in the supply wiring to the ecu? This would be pre-set to the exact voltage the ecu needs and assuming care was taken to avoid the plug/socket getting corroded would prevent this issue happening again. Obviously it will not stop the ECU from developing a hardware fault, but will go a long way to saving low or high voltage scrambling the memory it holds.

Another possible issue is dry solder joints, letting go due to constant vibration in a vehicle, especially being mounted on the metalwork close to the engine and drivetrain. I am sure that crashdata but these faulty units on a test rig and install a standard copy of good data. If they won't take data they get inspected for damage, but doubt they test all the solder joints as it is time consuming. A unit that repeatedly goes into fault at random likely has this issue
 
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Lenny HB said:
Found this via the Fiat forum, a lot cheaper than Crash Data.

www.ebay.co.uk

B0100-49 REPAIR SERVICE Fiat Ducato, Peugeot Boxer, Citroen Relay Airbag ECU's | eBay

Find many great new & used options and get the best deals for B0100-49 REPAIR SERVICE Fiat Ducato, Peugeot Boxer, Citroen Relay Airbag ECU's at the best online prices at eBay! Free delivery for many products.
www.ebay.co.uk
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Used him for my last repair but worked out dearer than crash data in the end.
Dispute my multiecuscan only identified a single fault of internal earth fault within the unit, he said it had an additional low voltage fault 12.6v so there was a charge for rectifying 2 faults.
I also read somewhere that this repairer had found additional faults and the cost was more than advertised.
Just seemed a bit odd to me.

However. It’s still good after 3 months.
Time will tell no doubt.

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This site contains affiliate links for which MHF may be compensated.
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Right I am a newbie and know nothing so please be gentle.
If this warning light is on does it fail the MOT?
Does it mean the airbag won’t work?Can you drive the vehicle with the light on?
Coukd you just disconnect it?
 
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