Airbag ECU failed again, advice appreciated

[DesandDek]

Hi all, I have read most of the information on the threads but still need advice.
Do we have it repaired (reset ) again £84 at last reset?
Do we invest in a new one £300 +(are they any better have the manufacturers sorted this problem of low voltage at crank)?
Do we invest in a reset interrogation piece of equipment £??? and do they actually reset the ECU?
When I received the ECU back from the repairer it mentioned the low voltage concern, our motorhome was then almost 4 years old so we decided to change the battery, We procured a Yuasa expensive battery, the best we could buy a YBX 5000. I checked all the terminals and rechecked all the circuit connectors and used Servisol cleaner on all connections.
We last used the motorhome 3 weeks ago on a trip to Cambridge so would not expect a low voltage on crank over.
But yes the light came on at the start of a journey locally to the New Forest.
I have checked the battery and the connections and tried various supposed reset procedures as on You Tube.
Before my retirement I was a industrial engineer and understand electronic applications PLCs etc so and find this problem unacceptable and still un resolved by the manufacturer.
If have monitored the battery since new and the lowest voltage ever was 12.5 volts
We have contacted the repairer by Email, no reply and then phone and there is no support from them only that the crank voltage is to low and it is not there problem, so we must have it reset again. Again Again. If the new unit resolves the problem then we will go down this route or if a reset piece of equipment is cheaper and works then this maybe the route to go
Any factual advice please.
Derek & Derith

 

[cgwcmlw]

Just to highlight another similar chat active at the moment....

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

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...

www.motorhomefun.co.uk

 

[Spriddler]

It seems curious to me that I've never heard of the problem occurring on cars or vans fitted with air bags.

(But I have to admit that I do enjoy the schadenfreude from having a faultless 27 yr old grey porridge Compass which is devoid of any complex electronics ).

 

[Phill D]

Your frustration is felt by many of us.
Sadly there appears no guaranteed fix from a reset ecu or a new one.
Some dealers do offer a guarantee on fitting a new ecu of up to 2 years.
Personally if it’s been reset once and failed in a short time I would look at replacing it.
But , it’s still a gamble

 

[SpeedyDux]

Getting the airbag ECU module repaired worked for us. 2 years later touch wood it hasn't gone inop a second time.

If I haven't driven the van for 7 days or longer I always use EHU to make sure the starter battery is fully charged. I wouldn't risk anything longer due to parasitic drains on the battery, even if it still shows a nominal 12.7v before cranking.

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[Folkranger]

It seems curious to me that I've never heard of the problem occurring on cars or vans fitted with air bags.

(But I have to admit that I do enjoy the schadenfreude from having a faultless 27 yr old grey porridge Compass which is devoid of any complex electronics ).

I asume that the system (and its weakness) is designed for vans that do not stand unused for prolonged periods. Mine went during covid when it stood for over 6 months and i assumed that the voltage was OK, not realising that the system fails at 12.5 volts.

 

[Phill D]

12.5v is around 80% state of charge.
That low level of discharge should not have the effect it appears to have on these airbag ecu.
It is simply poor design and a manufacturer that cares. Less about the quality of performance of its components.
A funster has indicated that the failures are mostly human error and a sensitive product.
IMHO there are cases when human error has been the problem but it is likely less than a few % of the cases.
You don’t read of this problem to the same extent on Renault or Mercedes converted motorhomes.

 

[Folkranger]

DesandDek
Mine failed during a 2020 covid layup and the battery was 6 years old so not the same situation.

Like you, we replaced the battery and had the ecu reset which in our case seemed to fix the problem.

I did buy a relatively expensive OBD2 reader with reset facility. It read the fault and told us that it could not be reset. (Sent it to Crashdata who then fixed it) and sold the OBD2 reader on ebay.

I did read that seatbelt connections could trigger this or similar fault so maybe this could be something to look into. There are quite a few threads which cover this issue.

I personally don't think that buying a new ecu will be much different from having yours reset but I have no evidence to back this up. It's a software problem and Crashdata just replace the faulty software with new.

 

[Dorset Diver]

After mine failed some time ago I was told that when starting the engine it pays to turn the ignition on and wait a few seconds for most of the dash lights to go out before cranking the engine. This is what I do now and I haven't had a second failure so far, but that could just be coincidence. Fingers crossed.

 

[Phill D]

After mine failed some time ago I was told that when starting the engine it pays to turn the ignition on and wait a few seconds for most of the dash lights to go out before cranking the engine. This is what I do now and I haven't had a second failure so far, but that could just be coincidence. Fingers crossed.

That is good practice and lets the ecu activate fully before any change in voltage.
Not fool proof but it certainly reduces the risk

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[Dorset Diver]

That is good practice and lets the ecu activate fully before any change in voltage.
Not fool proof but it certainly reduces the risk

I think it also lets the glow plugs do their thing, including using a lot of power, then switch off prior to the starter kicking in.

 

[Stealaway]

After mine failed some time ago I was told that when starting the engine it pays to turn the ignition on and wait a few seconds for most of the dash lights to go out before cranking the engine. This is what I do now and I haven't had a second failure so far, but that could just be coincidence. Fingers crossed.

That's a proceedure I've adopted with my three years old van from new.
But
My one failed on a touring holiday in France last month with the battery at peak performance.
Bugger.

6 days later the fault light went out again.
I've given up trying to understand why
It seems to make no sense.

 

[Sapper520]

After mine failed some time ago I was told that when starting the engine it pays to turn the ignition on and wait a few seconds for most of the dash lights to go out before cranking the engine. This is what I do now and I haven't had a second failure so far, but that could just be coincidence. Fingers crossed.

May be stating the obvious, starting procedure is in the vehicle manual.

However, the failures don’t seem to have any real pattern……other than what Crash Data claim.

 

[Bessy765]

Some engine management faults where the EML light comes on will clear if the same fault does not re occur after 6 starts, a heavier or extra earth strap is always a good idea. Fitting a battery master using the hab batteries to top up the engine battery may help.

 

[Dorset Diver]

May be stating the obvious, starting procedure is in the vehicle manual.

However, the failures don’t seem to have any real pattern……other than what Crash Data claim.

I prefer the much less confrontational way of giving info. Some people don't spend much time reading manuals.

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[Lenny HB]

However, the failures don’t seem to have any real pattern……other than what Crash Data claim.

I wouldn't believe anything they say.

 

[Sapper520]

I prefer the much less confrontational way of giving info. Some people don't spend much time reading manuals.

Sorry….didn’t mean to be confrontational.