C8 - airbags, airbag ECUs & side crash sensors

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kurnt29
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C8 - airbags, airbag ECUs & side crash sensors

Post by kurnt29 »

All C8s and 807s were equiped with 6 airbags as standard (driver, passenger, 2×seats and 2×side curtain). What are the actual differences in airbags and airbag ECUs?

Airbags for exaple look exactly the same, use same connector but have different catalog numbers written on them - that is for the airbag used on same place (right side curtain for instance), but different year of production. Are they interchangable even if they do not have same catalog numbers? If not, why not? What is different?

Same question goes for airbag ECUs. Are they interchangable?
Again same connector, same outside looks, but different year of production.

Side impact/crash sensors seem to be fitted as standard too. Where are they located?
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Re: C8 - airbags, airbag ECUs & side crash sensors

Post by GiveMeABreak »

You are being too general: The C8 and the 807 are essentially the same vehicle with cosmetic differences. When comparing a like for like model of C8 and 807 the airbags and ECUs will be identical and share the same part numbers. The only difference as one example would be the steering wheel airbag that obviously has a different part number as one has the Citroen logo on and the other a Peugeot logo.

Where these parts change - is to do with the different model specifications, engines, year of production and specification / trim levels and electrical architecture.

To answer your wider question, and talking about models in the whole range, not just the C8 and 807 in this case, their can be options for additional airbags to be provided (usually for rear passengers) as a factory fit option. In this case a different Airbag ECU will be needed to control these. Another example is how airbags are deployed, some models will have a 2 stage triggering of the airbags depending on severity of the impact - with a partial inflation for a smaller impact and a larger explosion and inflation for a severe impact.

Another factor can be based on whether the vehicle is equipped with help equipment such as a telematics unit that can call the emergency services ion later vehicles in the event of an airbag triggering event... so all these factors which types of airbags, airbag ECUs and control systems are employed.

Lastly, looks have nothing to do with capabilities. ECUs have different levels of hardware and software and are designed to do different jobs or support different functions depending on vehicle and function. Some are designed to work with a specific multiplexed data network system like CAN, VAN, CAN-CAN or CAN-VAN etc).

So my advice is if you are asking this with a view to replacing parts between a C8 and an 807, just post up the VIN of the vehicle if you require correct part numbers. You can then use these to search for the correct replacements. Do not guess!
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Re: C8 - airbags, airbag ECUs & side crash sensors

Post by kurnt29 »

Not to be too general, we are talking about cars with same number and position of airbags. Correct me if I am wrong, but mentioned vehicles all had 6 airbags, no additional options. Hence I believe that trim level or engine choice did not had anything to do with change in airbags catalog number.

I am aware of differences you have kindly stated, but let stay focused on C8/807/Ulysee/Phedra models between 2003 and 2009.

Regarding airbags:
Did they change from one to two stage triggering?

Regarding ECUs:
Was there an option for "help equipment - telematics unit?"
Was there change in data network system (CAN)?
Even if data network system was changed that should only affect ECU, not airbag itself.

Where can I check if parts are correct for particular VIN number / what software is needed?
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Re: C8 - airbags, airbag ECUs & side crash sensors

Post by GiveMeABreak »

You’ve asked a question, I’ve given you answers, so please don’t tell me what is and what isn’t relevant. I’ve told you that they will be similar or the same part numbers on SOME models like for like.

It makes NO difference on the quantity and location of the airbags. It is down to the Airbag control units, their software and type.

The VIN numbers are required for part numbers to ensure they are correct for your vehicle as I have already requested.

Yes, there are differences in the electrical architecture from late 2005 to full CAN. If the C8 has a Green backlight on the dashboard tachometer display it is VAN/CAN and if it has an Orange backlit display it will be full CAN (CAN CAN).

This is what will determine compatibility - the data signals on the vehicle networks will be different and this will affect other systems as each ECU can share and pass on multiplexed data - if the ECU cannot interpret it properly, it cannot use the data and more importantly it cannot send on the data in the correct format to the oither ECUs ont he network.

Yes - If you had a telematic option fitted like the RT3/RT4 these also can be VAN or full CAN versions and again can be linked to the airbag control ECU for emergencies. So as per my previous explanation - ECUs have to be of the correct type to work with the correct vehicle electronic architecture.

And further, regarding airbags, yes these did change around 2007.

As for 2-stage triggering, that is a general issue and will depend on the system fitted to your vehicle.

If it's a matter of locating a replacement part, it would save a lot of time to provide the VIN of the vehicle you want replacements for, so you have the right part numbers. With these, you can be assured the part will fit whether from an 807 or another C8 - it's the compatibility that is the issue - which is why the part number is critical.

I don't think I can put it simpler than that.
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Re: C8 - airbags, airbag ECUs & side crash sensors

Post by kurnt29 »

GiveMeABreak wrote: 19 Feb 2019, 23:48You’ve asked a question, I’ve given you answers, so please don’t tell me what is and what isn’t relevant.
Don't get me wrong, I am grateful for all your answers as many other readers will be. In your first answer you have described differences in airbag and ECU tehnology in general, but I was and still am interested in differences that appeared on C8/807 models during its production cycle.
GiveMeABreak wrote: 19 Feb 2019, 23:48It makes NO difference on the quantity and location of the airbags. It is down to the Airbag control units, their software and type.
Usually if vehicle has different number of airbags it also uses different airbag ECU. Most of them even have different connector so difference is easy to spot. But it seems like this is not the case for C8/807 (same main connector, different unit).

GiveMeABreak wrote: 19 Feb 2019, 23:48The VIN numbers are required for part numbers to ensure they are correct for your vehicle as I have already requested.
It is not VIN/part numbers I am interested in at the moment (though it is good to know we can contact you in case of need). I am interested in technical details that changed - for instance mentioned VAN/CAN multiplex change.


Airbags
Q: Did they change from one to two stage airbag triggering?
A: Yes these did change around 2007. As for 2-stage triggering, that is a general issue and will depend on the system fitted to your vehicle.

Q: Does two stage triggering appear on all airbags (seats & side curtains) or just for the two up front (driver & passenger)?

ECUs
Q: Was there change in data network system (CAN)?
A: Yes, there are differences in the electrical architecture from late 2005 to full CAN. If the C8 has a Green backlight on the dashboard tachometer display it is VAN/CAN and if it has an Orange backlit display it will be full CAN (CAN CAN).

Q: Was there an option for "help equipment - telematics unit?"
A: Yes - If you had a telematic option fitted like the RT3/RT4 these also can be VAN or full CAN versions and again can be linked to the airbag control ECU for emergencies.

Q: Will a non-compatible airbag/airbag ECU combination return error or will it deploy airbags if connected?

Side impact/crash sensors
Q: Fitted as standard. Where are they located?
A: Side impact/crash sensors are located between B pillars and front seats (each side), underneath the carpet. To access one, plastic element covering carpet on one side and being covered with door seal on other has to be removed. Once removed, carpet can be lifted and side impact/crash sensor can be seen in metal shielding.

Side impact/crash sensor with shielding (rusty metal):
Image


All Q&A are related to C8/807 twins and not to other cars (not general).
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Re: C8 - airbags, airbag ECUs & side crash sensors

Post by GiveMeABreak »

So you have my answers to your questions.
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Marc
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