55 Plate 1.6 Picasso Desire airbag issue

[Tam]

Hi guys, new to the forum so please forgive me if I have posted in wrong section.

On the above car I have a dash warning saying "Airbag Fault" when starting which goes out after a couple of minutes driving but the airbag warning light stays on constantly. I have got problem code P1801.
I would like to try and sort this myself but i'm not sure where to start looking. I have been advised to check wiring under a seat and comms 2000 unit.

Can anyone offer any advice or tips where to start please? Any input would be greatly appreciated.

Thanks in advance

Tam

[Hell Razor5543]

Hello Tam, and welcome to the FCF forum.

The first thing to do is to see if there are any members near you with a Lexia system (or who know the relevant codes), as this can help narrow down the problems. You can (if you are careful) take a look under the seats to see if there are any connector issues, but if you see one disconnect the battery first, and then wait 30 minutes (you can get away with less, but I cannot remember the minimum time needed). If you were to find a loose connection, and plug it in with the battery connected, it is possible that that would set off the airbag.

Here is the link to the Lexia map, with members who are willing to help;

http://www.frenchcarforum.co.uk/forum/v ... 19&t=29178

[Tam]

Hi James and thanks for the welcome! I was given this code by a garage yesterday. It says "P1801 drivers level 1 airbag ignitor open circuit." Now I'm not sure if it was a Lexia system he used. Is this the descriptor you meant? I have had a look under the seats and passenger side has a little connector on the cross bar at front of seat, would this be what i'm looking for or is it some connectors underneath near the battery? Sorry about the questions but I'm happy to try most things but this has me stumped. The last post I see from a Lexia owner in my area is in 2010 so I wonder if he is still available? Might also invest in this software myself if it isn't too expensive.

Thanks

Tam

[RichardW]

Hi Tam, I'm not that far from you and have Lexia.... That fault relates to the steering wheel airbag - most likely the COM 2000 unit, but it could be a wiring fault or similar. It might be possible to test to see if it's the COM 2000 by disconnecting it and putting a resistor in instead, but not idea how easy that is! There's a guy in Bradford that repairs the COM units, sometimes can repair air bag faults - search COM 2000 repair on e-bay.

[Tam]

Hi Richard, great stuff mate! I would have no idea how to go about the resister thing. If I knew it was this comms 2000 unit I would replace that but it's the not being able to tell if it is the unit or indeed as you say, a wiring fault that is a bummer. Would this rule out the wiring under the seats then? Would Lexia pinpoint the fault or narrow it down a tad or is that the code you'd get from Lexia anyway?

Thanks again

Tam

[wheeler]

Picassos don't normally suffer from underseat wiring problems as the pretensioners are in the inertia reels in the B pillar rather than in the stalks in the seat.

[Tam]

Thank you wheeler-much appreciated!

[Tam]

Have lived with this but decided to move it on, I contacted Graeme in Bradford via Ebay who does the Comms2000 repairs, he advised it could be anywhere in the airbag circuit and after a great and helpful phone conversation, I decided to go down to Bradford and he checked it out. He ruled out comms2000 unit and said fault could be anywhere on airbag circuit as code suggests broken, corroded or loose wire. I have to start with the Airbag ECU(I take it he means connections to it) which I believe is behind the lower centre facia under ashtray etc. To be fair the guy didn't charge me a penny as he couldn't fix it!

Anyway, any further ideas to check/do would be great .

Edit: I have been reading up on doing continuity testing with a multimeter

[GiveMeABreak]

A few notes of caution:

• If playing with airbags - switch ignition on and check that the airbag light comes on and then goes off, switch ignition off and disconnect battery negative and secure it so it can't touch the battery negative post.
• Wait 5 minutes afterwards before removing anything (to deplete any residual electrical charge from the Airbag ECU power reserve);
• If the airbag light is permanently on on not funtioning properly, then wait 10 minutes after disconnecting the battery.
• Never remove the Airbag ECU without first disconnecting the connector under any circumstances.

There is also a general warning never to use an Ohmmeter or any other source of electrical current on the pyrotechnic devices due to risk of deployment.

If you need any procedures / Diagrams for accessing the Airbag ECU, just send me a PM with an email address (including your VIN), so I can send the PDFs to you (don't post your email here on the forum - spambots)

[Tam]

That is so kind of you-Thanks!
PM sent

[Tam]

Thank you so much Marc, the pdf's are great.
Another question if I may to you guys? Will Lexia tell me if any crash data is stored on airbag ecu? As I don't have any history of the car i'm wondering if it has been in a bump and the data is causing this issue.

Thanks

[Tam]

Ok, got a Lexia on this today by a Citroen guy and the code I was given by another garage isn't showing P1801. Lexia cannot connect to airbag ECU. Guy reckons it's corroded/broken wire, ecu or BSI. Here we go again.

[Tam]

Further update, I bit the bullet and took off the lower facia and had a physical look at the wiring to/ from the ECU, looked clean and no obvious corrosion, took airbag off and checked connectors around that and they all looked secure. I know that it isn't a comprehensive check but thought i'd try visual inspection anyway. I have ordered an ECU from ebay to see if a swap might help, I will sell on again if it doesn't. The BSI also looked clean but I know that counts for nothing. If it points to a BSI fault, I will call it a day as I was told about £600 and get another Pic.

[myglaren]

If it seems that there is a BSI problem - or other ECU fault, it may be worth your while to call Graham in Bradford.
Several members have reported great satisfaction with his services.

[Tam]

Thanks myglaren, I already drove down and met Graeme, ruled out my comms2000 but couldn't say where fault lay. Lovely guy who gave me a few pointers.