What Is The Driver's Level 2 Airbag?

[sifaan]

Hi all

 

Managed to get my old diagnostic kit upgraded to use the new versions of diagbox; since I got the car it has displayed "Airbag fault" in the multifunction, but never got around to fixing it because there were always more urgent things to deal with (and I assumed it was the passenger airbag under the seat wiring)

 

But with the diagbox it turns out that the error is "Driver's level 2 airgbag igniter open circuit"

Where is this airbag? Can the igniter be replaced? Or could it be that the car never had that airbag to begin with?

 

I'm figuring it's not the one on the steering column, cos I had the com 2000 replaced some time back (for the horn not working) and the airbag fault existed before and after that; and furthermore the configuration shows that the steering column airbag is not present.

 

Thanks

/Sifaan

 

[paul.h]

This is from a description of the mark 1 C5 air bags in the Citroen manuals so it looks as if the steering wheel airbag unit needs replacing -

 

3. front airbags

The front airbag is a complement to the seat belt, designed to activate in the event of a violent front impact.

Its role is to interpose itself between the front occupant(s) of the vehicle and the dashboard, to absorb their projection forward at the time of a violent frontal impact and thus to limit the risk of serious injury to head and chest.

The airbags are not deployed by only a slight front impact, by a rear impact or by the vehicle overturning, as they would not be of use in these instances.

The driver’s and passenger’s front airbags are of the adaptive type.

The power of the front module generator is linked to the severity of the front impact.

The driver’s and passenger’s front airbags have a double generator and two connectors, so there are said to be 2 deployment levels.

As a result, the front airbags deploy at two levels separated by a variable delay (in the order of milliseconds) depending on the severity of the impact :

• In a violent impact both ignition devices are triggered, and the airbag thus deploys very rapidly to protect the driver or the passenger
• In a less substantial impact, the airbag ECU decides to ignite only the first level, so the airbag deploys a little less rapidly. The second level is deployed, but with a longer delay, not in order to protect the occupant but to guard the emergency services from a random triggering

The airbag ECU decides the triggering strategies, depending on the nature of the impact.

[sifaan]

This is interesting; in the configuration screen it says

Level 1 Driver's Airbag - Yes

Level 2 Driver's Airbag - Yes

Steering Column Airbag - NO

Passenger's Level 1 Airbag - Yes

Passenger's Level 2 Airbag - Yes

Passenger's airbag deactivation switch - yes

 

Could it be an incorrect configuration (how can the steering column airbag not be there?)?

I'm trying to see what it should be from VIN on service.citroen.com but it seems to be down currently...

[paul.h]

Steering column air bag - could this be an optional knee one if not the driver's one on the steering wheel ?

[sifaan]

I doubt it Paul; probably my car doesn't have a knee airbag, based on Haynes:

(btw what should I look for to confirm it?)

 

Both a driver's and passenger's airbags are fitted as standard equipment to models in the Citroen C5 range. One driver's airbag is fitted to the centre of the steering wheel, while another may be fitted at knee height (post-facelift models only). The passenger's airbag is fitted to the upper surface of the facia, above the glovebox.

The airbag system comprises the airbag unit(s) (complete with gas generators), impact sensors, the control unit (with integral crash sensor) and a warning light in the instrument panel.

Seat-mounted side airbags and overhead curtain airbags are also fitted on certain models, and seat belt tensioners are incorporated into the seat belt reels

 

Based on the above, the level 1 and level 2 should be the side and curtain airbags (although I don't know which is which). Apparently renewing the side and curtain airbags is tricky (beyond the realms of Haynes) so probably there isn't even a way to check if the car came with it - apart from perhaps service.citroen.com which is still down.

 

I'm thinking to turn off the faulty airbag and turn on the steering airbag in the config - because even if I have a level 2 airbag it's not working; and when the citroen site comes back up try and see if I should have it (in which case it probably means a very expensive repair!)

[paul.h]

Haynes shows a picture on page 12.20 of the knee air bag, located below the base of the steering column shroud, a bit to the side, next to the central console.

 

I have read the above differently to your last post. Level 1 and 2 only applies to the steering wheel and passenger front air bags. They can be inflated at 2 different rates depending on the severity of a crash. Rate level 1 is for  a less severe crash and rate level 2 for a worse crash. In both cases though both igniters go off for safety but in level 1, they go off together and in level 2 there is a time gap between them.

 

From this your 'the error is "Driver's level 2 airbag igniter open circuit"' I see as meaning the steering wheel air bag has a problem with its second igniter. Hence in a severe crash, it would not inflate as quick as it should. It may need a new steering wheel air bag to fix it. With the air bag warning on, it may be the air bag system is disabled but I am not sure.

[sifaan]

Hi Paul, looks like you were correct after all

The configuration for the side and curtain airbags are on another menu (and it seems my car has side and curtain airbags for driver and passenger)

I was able to deactivate the level 2 airbag in the configuration (so now the pesky error message doesn't appear) but it didn't let me enable the "steering column airbag" (so perhaps that does refer to the knee airbag that were fitted to the facelift models)

 

Now, I'm inclined to think my Com2000 is fine, because the unit was replaced sometime back and the airbag error was there before that as well.

Perhaps it's the wires under the passenger footwell that are the problem?

 

I took a look at it, and actually there are 4 connectors coming in (at least, from the nearside of the passenger footwell) and 5 connectors going out (at least, on the offside)

I was able to unplug and refit two of them (the brown and the light blue), but the locks on the other 2 were different (and have more wires through them) and I left them until maybe I could get some advice how to release them?

Picture at http://cl.ly/image/3g3y3W0o0l14

[paul.h]

When you replaced the comms 2000 unit did you re-use the old air bag since the igniter will be inside the airbag ?

[sifaan]

Hi

 

The old airbag was reused; the reason for replacing the comms 2000 was because the horn stopped working (apparently the ribbon cable or something tends to give) so i meant to say that it can't be faulty communication of the comms 2000 that is the problem.

 

Do you think the Airbag/igniter needs to be replaced, or could it be the connecters in the footwell?

 

/Sifaan

[paul.h]

Your error message is for the igniter in the airbag, so my best guess is that the airbag needs replacing, unless you just live with the fault and drive carefully.

[sifaan]

hmmm - just to confirm, does the typical problem with the connectors under the passenger footwell result in a different error message?

[paul.h]

I do not know but the following is also from the Citroen procedures for a mark 1 C5 from RPO no. 9618 -

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3. Reading/deletion of faults

The following faults can be read using the diagnostic tool :

• Supply voltage fault
• Fault on ignition device for first level of deployment on driver’s side (short circuit to the +, short circuit to earth, open circuit)
• Fault on ignition device for second level of deployment on driver’s side (short circuit to the +, short circuit to earth, open circuit)
• Fault on ignition device for pyrotechnic seat belt module on driver’s side (short circuit to the +, short circuit to earth, open circuit)
• Fault on ignition device for pyrotechnic seat belt module on passenger’s side (short circuit to the +, short circuit to earth, open circuit)
• Fault on ignition device for first level of deployment on passenger’s side (short circuit to the +, short circuit to earth, open circuit)
• Fault on ignition device for second level of deployment on passenger’s side (short circuit to the +, short circuit to earth, open circuit)
• Fault on ignition device for chest-type lateral airbag on driver’s side (short circuit to the +, short circuit to earth, open circuit)
• Fault on ignition device for chest-type lateral airbag on passenger’s side (short circuit to the +, short circuit to earth, open circuit)
• Fault on ignition device for curtain-type lateral airbag on driver’s side (short circuit to the +, short circuit to earth, open circuit)
• Fault on ignition device for curtain-type lateral airbag on passenger’s side (short circuit to the +, short circuit to earth, open circuit)
• Passenger’s airbag deactivation switch fault (open circuit, short circuit to the +, short circuit to earth, change of ignition switch status, resistance fault)
• Passenger’s airbag deactivation fault
• RH lateral sensor fault
• LH lateral sensor fault
• Fault internal to the airbag ECU (energy reserve)
• Airbag ECU fault
• Fault on deployment of pyrotechnic seat belts
• Fault on deployment of front airbags and pyrotechnic seat belts
• Fault on deployment of airbag
• Rear impact detection fault
• Fault on the VAN network
• Configuration error fault

4. Reading of the parameters

Only one reading of parameters is possible : Passenger airbag deactivation switch status (not configured, ON, OFF, faulty).

 

5. ACTUATOR TESTS

There is no actuator test in existence for this ECU.

 

6. Configuration

The following parameters can be configured using the diagnostic tool

Title / Parameter status

Pyrotechnically pre-tensioned seat belt / No/yes

Level 1 driver’s and passenger’s airbags / No/yes

Level 2 driver’s and passenger’s airbags / No/yes

Passenger’s airbag deactivation switch / No/yes

Lateral sensors for the airbags (left and right) / No/yes

Chest type side airbag (left and right) / No/yes

Curtain type side airbag (left and right) / No/yes

----------------------------------------------------------------

 

The VAN is the Vehicle Area Network (from memory so may be wrong - coastline may help here) and maybe this would cover the wires and connectors.

[paul.h]

Was the comms 2000 unit replacement a new one or a used one since this came from a search on Citroen air bag VAN fault

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Citroen all makes. Airbag light on.

 

Fault code relates to drivers airbag trigger 1 and 2. This is a break in the contact ribbon behind the steering wheel. A new or stalk / comms unit is required.

 

Citroen C2 airbag light on (internal fault on VAN network)

 

At first glance this fault appears to be an internal problem in the airbag module. However it is often caused by the steering functions ECU. rectify by replacing steering unit.