Peugeot 206 1.4 HDi intermittent airbag fault

[dfabrici]

Hi guys!

I’m experiencing a strange issue with my 206 1.4 HDi from 2004. All was well until a few months ago, when it gave an “airbag fault” and “passenger airbag deactivated” message on the center display. I now got time to take a look at it with Diagbox/planet (I set it to French language to accommodate for translation errors, not so uncommon), and it comes up as an intermittent fault about “capteur de sécurité”, which translates to “safety sensor”. No additional info or codes are given. However I’m a bit at a loss. I’ve studied the diagrams on SEDRE but there’s nowhere any component with that name.
Consider that my car only has the standard driver and passenger front airbags, no side or curtain ones. So I have no connectors under the seats nor any additional acceleration sensors. I tried shaking the looms around and near the plugs on the ecu and com2000 but to no avail, never been able to reproduce the issue. Sometimes it just pops up on its own. If I cancel the codes, it clears out and can be one day or a week before it comes up again, it often also clears on its own.
I’ve also heard that a weak battery could give these symptoms, but mine is about 3/4 years old and tests good with a battery checker, I don’t know if it’s worthwhile to replace it anyways.

Thanks in advance for any help!

Have a nice day

[mickthemaverick]

This type of intermittent issue often turns out to be a dirty connection somewhere in the circuit. I'd suggest you disconnect the battery and then go through all the fuses checking for cleanliness and stability, then unplug and check all the plug pins and socket connectors for dirt/corrosion. Give them a spray of contact cleaner and reassemble. I'd do all the plugs around the fusebox as well as any others in the airbag circuits Good luck

[dfabrici]

Hi! Thanks for answering!
I guessed as well and will make a “cleaning tour” of all the connectors.
I was however wondering if anyone of you had any ideas about which component it could be fussing about, to “focus” my research a bit more, to confirm whether there could be corrosion or similar on more specific pins.

Thanks!

[PaulC5]

Can you list the fault codes that you are cancelling and their English definitions.

[NewcastleFalcon]

This may not be much help, but I suspected from the description that "capteur de securite" had a reasonable chance of being a "crash sensor".

AI came back with this.... "A capteur de sécurité (safety sensor) in an airbag circuit is a type of sensor that detects collision forces and helps determine whether the airbag should deploy. It works alongside other sensors to ensure that the airbag system activates only under appropriate conditions, enhancing passenger safety during an accident.
repairmysrs.com
elprocus.com

I have no direct experience of your Peugeot 206 but do have experience of replacing the side impact crash sensors in a Renault Clio to correct an airbag light on fault. On the Clio they are mounted on the inner sill inside the vehicle, and can be subject to water ingress. as a result of soggy passenger footwell which is a fairly common occurrence in the Clio.

There may also be a frontal impact crash sensor in the vicinity of the bonnet catch.

The successful conclusion is here... viewtopic.php?p=790922#p790922

These are the side-impact crash sensors as applicable for the Renault Clio of 2003 vintage which sorted the Airbag light on for me. Wouldn't be too surprised if the Peugeot 206 2004 had something very similar.



Neil

[dfabrici]

Hi all

Thanks so much for your contributions.
Later I’ll send a screenshot of the pp2000 screen in English.

I also came to the conclusion that it could be something like that, however from what I gathered from Servicebox exploded views, there is no such sensor in my car, the side ones are present only in case of side airbags, and it looks like the main front sensor is integrated in the airbags ECU (that has indeed a front pointing arrow on it)…

[dfabrici]

Hi all,

As promised here a few pictures of the fault codes, in French and in English. I also took a picture of the ecu config. No live data is available from the airbag ecu.

Thanks in advance!
Davide

[NewcastleFalcon]

I was however wondering if anyone of you had any ideas about which component it could be fussing about, to “focus” my research a bit more, to confirm whether there could be corrosion or similar on more specific pins.

Thanks!

Can't offer anything specific on the Peugeot 206 Davide. I have sorted airbag light on with the Renault Clio, where the usual suspects are the wiring connectors under the seats, and the side-impact sensors, and the Nissan Micra where the solution proved to be a replacement SRS ECU from a scrapyard.

On the Clio, the termination of the wiring at the seatbelt pre-tensioners is a little plug which pushes into a socket on the pre-tensioner itself. These can become loose through movement of the seat and may simply require pushing in to re-make a positive contact enough to pass the SRS ECU's initial self-test.

Neil

[Bordonbert]

I can offer some info which may help. I worked in electronics design so to a degree wiring and connectors are a known field. I have a pair of 206 GTis (S16, je crois sur le continent). I had this exact problem with airbag lights appearing on the dash. I tried everything to identify the fault with PP2000 for weeks to no avail. The reported fault even changed from day to day. It came down to a known issue which is reported widely on the internet. I believe it may have been mentioned here already but the airbag connectors under the seats are - well frankly - absolute pants! Considering the currents and voltages and the sensing requirements for diagnostics involved, they are lightweight for the job, have an extremely limited number of break/make cycles which always points to a short life in demanding situations and almost inevitably cause problems on older 206s and many other Peugeot models too. The only truly long term solution is to change them out not clean them.

There is one connector under each seat feeding the side airbags if fitted, and one under the steering column feeding the passenger airbag in the dashboard above the glove compartment. Of course there is also the dreaded clock spring spiral wiring to the driver's airbag in the steering wheel. The three connectors under seats and steering column are best replaced with better types. If your soldering is up to par a good alternative is XT60 type model car battery connectors. These are cheap and easy to source. I used Amass MR60 shown below. They are small and compact but are designed to handle high currents.

Whatever you choose it should be gold plated and high current capable. The piddly little things Peugeot chose and others like them are just not man enough for the job. The sensing system relies on the lines having a specific low resistance range for accurate diagnostics. When the connectors age they do not necessarily lose contact, the resistance changes and goes out of range causing a fault to be registered when there is nothing wrong with the airbags or wiring continuity at all.

Should you find the worst case and changing out the connectors doesn't cure the problem then it could be the airbag control unit and its 50ish-terminal connector in front of the gearstick under the central console. These are cheap second hand and are ok as long as they are exact duplicates and have not come from a crashed car where the airbags will have triggered. Or it could finally be the steering wheel clock spring spiral connection which often goes faulty. It can be repaired but it isn't a job for the inexperienced. You can send away your unit for a repair by online specialists. There are also specific instructions online you could look up as to testing it with low value resistors, I think around 2.2ohm, to rule it out as the cause.

Hope some of this might help.