Air Bag/pretensioners Fault Citroen C5 2009

[146fossil]

Air Bag/pretensioners Why me… 
Ok gents need your valued expertise and will be more than happy to pay for a final fix with hard earned notes or pints…
Right here goes…..it’s the Air Bag/pretensioners fault message on a Citroen C5 2009 2.0d tourer. Regardless if I disconnect the battery and reconnect (following the battery disconnection process) the fault message still show up on the drivers display console along with a permanent service light which has not gone out since the fault first appeared.

At the same time the seatbelt information warning display screen located in the roof next to the rear view mirror shows only a singular symbol of a seat/belt/airbag with a No2. All other seat passenger occupancy dot lights are off since the fault has occurred.

So far I’ve had the fault read by Lexia which comes up with (passenger lcd display initialization fault).. Was told to change the seatbelt information warning display module located in the roof next to the review mirror. This has now been done ensuring that the original and replacement have same model number. I even had the fault rest with Lexia but immediately the fault came right back up with the same fault message.

I was then told it has to be the Air bag ecu module.. So now have replaced the ecu air bag module and again have the same fault.. I’ve now had the fault diagnosed my Lexia and with a snap-on diagnosis and both come up with the same fault…

Help, what else can it be.. I’ve even disconnected whatever connections I could see under the seats and sprayed electrical contact spray in the connectors but still shows this irritating fault.. On top of this the cars got an MOT in June..
I’ve googled night and day for a fix even to the point my wife thinks I’m having an affair over the net.. This car is slowly breaking me (financially and in marriage)… Help

[GiveMeABreak]

First, can you check whether the front passenger seat Airbag has been deactivated with the key (in the glovebox) if this has been switched OFF with the key, then the ceiling light (with the number 2) will be illuminated. Always best to check the simple things.

Can you post up your VIN and I'll have a look to see if there's anything I can suggest.

A couple of things. You say you have been told to replace various modules - who told you this? Before replacing any ECU, you should always get a printout of the configuration settings from Lexia stored in the ECU as in many cases you will need to configure the ECU when replaced. There are certain settings that have to be configured, otherwise the warning light will remain on and the system will be deactivated.
Can you be explicit in any of the Lexia codes returned - specifically the exact fault code(s) and message(s). I'm not really interested in the snap on codes. There should be a list of these stored after running a global test. It is best to read these, clear them and then re-run the test to eliminate the historic faults.
My concern now is that the airbag ECU has been replaced and the system may not have been coded properly if at all, compounding the original issue.

[146fossil]

Ok thank you so much for reading my post Marc.. The modules so far replaced was advised by a (mobile air bag man in the Berkshire area ) he 1st linked it up with the Lexia and advised that the Lcd display module would need replacing from the code stored in the ECU. He stated that this is a simple plug and play module.. Once replaced I called him up and said that the fault still showed, he responded by saying "that the LCD module was a simple plug and play and the information comes from the air bag ECU so the next point would be changing the Air bag ECU".. So after loads of googling I managed to find the same ECU with the identical seral numbers.. But fault still showed.. I called him up again and he responded by saying "if the ECU matched the same serial numbers then the fault will be like finding a needle in a hay stack"...

I then decided to try an in depended garage who had the snap on tool to see if a new fault showed, but regardless even with a few fault resets the fault came back up within 1sec.

Over the weekend I will call the Air bag man out again and get the fault code cleared and will also get him to re run the tests using the Lexia.. I'm 100% convinced that I will get the same response from him, but this time I will get the code and share with you guys... I will also provide you with the VIN tomorrow...

The suggestion of key in the glove box to deactivate the passenger air bag. I wish this was associate to my problem but no such luck.. Have even tried turning the key in the glove box numerous times just in case this had some magical fix...

I basically been driving my car for the last 5 months then one morning drove to my nearest petrol station, filled up and got back in only to blessed with this curse..

Thanks for you help so far.. Will keep you posted..

[nick haddon]

Did you ever find this fault? , I have the same problem with mine a citroen specialists says its the BSI!

[demag]

First off don't get buying loads of stuff to fit. Get a Lexia diagnosis first. I'm not too far from you Nick but unfortunately am on hols next week. If you're not too desperate I might be able to get over in a couple of weeks but believe me I am no expert but have got a Lexia and been online with my car a few times.

[nick haddon]

My car is out of MOT now, at Citroen specialist at the minute he has checked all wiring and read codes but he thinks it is a BSI fault as he can't communicate with the seat belt unit within the BSI, this is the same display as airbag LED unit (unit replacement was tried by auto electricians) ,seat belt LED's have not worked since this fault appeared, this is the 4th garage it has been too, Peugeot specialist with Lexia didn't get back to me, local garage snap on didn't know where to start, auto electricians, snap on, wanted a blank cheque to dismantle dashboard etc, and this Citroen specialist Lexia again . I have I carsoft CP2 myself that says passenger air bag deactivated,LED not defined permanent fault, airbag has been checked and is ok. I don't know what to do now Citroen are quoting £700 +vat if it is BSI, Do I throw Best part of £1000 at it or sell it as spares and buy something else?

[GiveMeABreak]

Hi and welcome to the Forum.

To help us understand a little better, it would help if you could be a bit more precise:

Forget for the moment what the other garages have and haven't said, as that is meaningless when they are guessing or trying to extract money from you. I know it is frustrating when you are getting conflicting info from garages - but we don't know anything about the car - so best to start from the beginning.

What is the actual problem you have - be specific, what dashboard lights are on - if any, or are there any messages being displayed?
What is the exact component, if anything, have you already replaced?
What, if any, are the exact fault codes or messages you have from your diagnotic tool?

Don't spend out any money just yet. It might be worth getting it on a Diagbox first, so that we can determine what the exact fault codes are and the suspect areas.

Post up or PM your VIN and I will take a look at the wiring diagrams for your C5 to see what the possible suspect areas to check. Once I have this I can point you in the direction of the correct fuses and any wiring / parts to check (they can differ depending on model, year and options).

[nick haddon]

Passenger air bag disabled light is on and service light, airbag or pretentioner message everytime you start. Also have a P2297 anti pollution fault which I think will be the oxygen sensor in the cat. The priority is the airbag fault.
I can see the passenger airbag switch with my reader and it sees it as on, if I turn it to off it sees that as well, when I collect the car again tomorrow I will ask what the actual code is from the lexia for the fault

[nick haddon]

Vin is VF7**************[VIN obfuscated, can be read by forum staff]********* C5 TOURER EXCLUSIVE

[GiveMeABreak]

Ok, a 2.0 HDi 163 PEF Manual gearbox 6 - I'll have a dig now to see what I can find, and I've masked your VIN.

[GiveMeABreak]

What actual unit was replaced? Was it the roof console LED display unit or the actual Airbag ECU?

An airbag system fault will trigger the following:
Fixed illumination of the generic "SERVICE" indicator on the instrument panel.
Display of a symbol and a message for 10 seconds on the screen of the instrument panel.
Emission of a sound by the steering wheel switching module.

So as there are many individual components to the Airbag and pretensioner system, we really need all the fault codes generated - then I can help you try and identify the reason and suspect areas from the code.

[nick haddon]

Hi Marc,
Thanks for your interest, all that has been changed was display in the roof by auto electrical place, it made no difference and they were going to send it back. I have checked connections under the seat and to airbag ecu, also proved wiring to passenger airbag, it sees the disconnection if I unplug it and I can clear that again with a 2.2ohm resistor or reconnecting the airbag, the switch to disable airbag works. The Citroen specialist can see the airbag fault and will have a code but he says he cant see the seat belt interface, it is greyed out on the lexia and can't communicate, he has spoken to citroen and they say seat belt unit is part of BSI so he thinks the BSI is faulty? I don't know what to do now, I don't have a close by dealer anymore, the closest is Stourbridge and they couldn't even manage to put 3 fuses in the auxiliary fuse box to enable a genuine towbar on the C4 I had before! I had to sort that out myself with help of google etc. C4 was a good car but not quite big enough so hence the swap to a C5 Tourer which I love( or did till this problem). I only have icarsoft CP2 reader but seems quite good. I will ask what codes tomorrow when I collect it and pay more wasted money!

[GiveMeABreak]

Ok thanks for that extra info Nick. I’m going to look at some data concerning pretensioners this morning and await the code info from you.

The BSI is the master computer if you like that talks with all the other ECUs. It is the Airbag & Pretensioner ECU that deals witht the airbags and the pyrotechnics - there isn't a separate ECU. So if there is no dialogue with the airbag ECU then that will be the likely problem.

That has been a recent case on another vehicle that triggered a seatbelt pretensioner to fire when going over a bad pothole! No airbags would trigger as there was no actual impact detected by the side and front sensors, but it was enough to trigger a pretensioner. Changing the particular seatbelt and pyrotechnic seemed to resolve the situation. The noise of the pothole impact also could mask the pretensioner firing. I’m not saying the same has happened to to you, but it is another possibility to consider.

I’ll await the extra info from you, as Diagbox will have more detailed info than a third party scanner. I’ll wait to hear from you after you pick the car up.

[nick haddon]

Hi Marc,
I have collected the car and have the printout from the Lexia, The driver and passenger airbag rectangle is green say SAC_Autoliv( 1 faults) and underneath is has 7362 Passenger's airbag deactivation switch LED, properties. cause is blank, Distant and under that says Characterisation of the fault Not Characterised.
Multifunction display EMF_C( 1 faults) F8EB absence of the screen permanent plus, is this because I don't have sat nav? says not characterised again.
There are other engine related faults that I can sort at my leisure

[GiveMeABreak]

Ok, thanks for this - I'll have a look now....