Airbag Testing...

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Rhothgar
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Airbag Testing...

Unread post by Rhothgar »

Time for me to start considering the next fault.

No communication with AirCon and Airbags!

So I took the airbag ECU out earlier and checked continuity on serial communications line from Pin 13 OBD to Pin 14 at the ECU. Obviously didn't want to load test it and couldn't as battery was naturally disconnected.

So how does one safely go about testing faults in the airbag circuit.

I could do a continuity test to the airbag ECU power (unplugged) but as a few will know load-testing is the way. I've just read some warnings about explosives being accidentally triggered.

I can obviously tear down the airbag ECU connector and back probe it but is it safe to do? Just on about testing power and ground to it in the first instance.

Is it safe for instance to take a voltage measurement whilst ignition is switched on to see if relevant pin is live?

Also, I could power probe the power pin (pin 1 from memory or is that ground and pin 15 is power - already forgotten so will check manual again before proceeding).

Powerprobe will tell if it is positive or negative without applying power or ground.

Was thinking of powering power pin whilst Lexia was trying to communicate and then grounding the earth if first option doesn't work.

Then if it reads, it should prove that either power or ground is an issue. Most likely to be power.

Are the internals known to go? I'd doubt it is strippable in its metal casing. I didn't pay to much attention to it. It's a Sagem-Autoliv.
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mickthemaverick
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Re: Airbag Testing...

Unread post by mickthemaverick »

Roger, when you start a new thread about a problem you need to specify which car you are talking about, as not everybody follows all the threads to know what is what!! :)
I used to be indecisive, now I'm not so sure!
I used to ride on two wheels, but now I need all four!
Rhothgar
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Re: Airbag Testing...

Unread post by Rhothgar »

mickthemaverick wrote: 02 Mar 2026, 17:00 Roger, when you start a new thread about a problem you need to specify which car you are talking about, as not everybody follows all the threads to know what is what!! :)
Just in general Mick!

But specifically about the Xantia S2 HDi LX 110 RHZ Super Fandango War Horse Special...
wheeler
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Re: Airbag Testing...

Unread post by wheeler »

Have you tried to communicate with A/C with the engine running?, something at the back of my mind is telling me that the older A/C systems only talk to Lexia when the engine is actually running.
Rhothgar
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Re: Airbag Testing...

Unread post by Rhothgar »

wheeler wrote: 03 Mar 2026, 14:54 Have you tried to communicate with A/C with the engine running?, something at the back of my mind is telling me that the older A/C systems only talk to Lexia when the engine is actually running.
Good question. I cannot recall but I shall try.
Rhothgar
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Re: Airbag Testing...

Unread post by Rhothgar »

Well that was a nightmare.

Used mate’s IM608. Reads airbag modules.

It’ll post detailed info up when I’ve eaten.

Plug Lexia in. Do full read. Lexia blows and laptop blows too! Not plugged it on but sure it has blown as it normally beeps when it is down to 7% battery.

152C Seat belt trigger 2 open circuit.
Rhothgar
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Re: Airbag Testing...

Unread post by Rhothgar »

Luckily laptop battery had died without warning and Lexia is fine too.

Weird how that won’t read airbag ECU.

I see 152C is the usual connectors under the seat and best solution is to either solder the terminals rather than relying on crimp terminal or get rid of connector entirely.

I couldn’t see how to get into them!

Also looked to be some discolouration. Under magnification it doesn’t look like verdegris. Looks more like a conductive grease perhaps. Hard to tell.

Need to find out how to get connector apart. Issue uploading images at minute. HTTP ERROR

EDIT. It’s the damned forum time out causing the issue!!! Time’s out before you can type a message.
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myglaren
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Re: Airbag Testing...

Unread post by myglaren »

Rhothgar wrote: 03 Mar 2026, 19:53 EDIT. It’s the damned forum time out causing the issue!!! Time’s out before you can type a message.
That is unusual Roger. I'm often very slow posting but have never had a timeout.
Rhothgar
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Re: Airbag Testing...

Unread post by Rhothgar »

myglaren wrote: 03 Mar 2026, 20:38
Rhothgar wrote: 03 Mar 2026, 19:53 EDIT. It’s the damned forum time out causing the issue!!! Time’s out before you can type a message.
That is unusual Roger. I'm often very slow posting but have never had a timeout.
You obviously don’t ramble on as much as I do Steve!!!!

Is this on mobile you’re taking about it or PC?
Rhothgar
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Re: Airbag Testing...

Unread post by Rhothgar »

Oooooo LOOK what I’ve just found!
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myglaren
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Re: Airbag Testing...

Unread post by myglaren »

Rhothgar wrote: 03 Mar 2026, 21:35
myglaren wrote: 03 Mar 2026, 20:38
Rhothgar wrote: 03 Mar 2026, 19:53 EDIT. It’s the damned forum time out causing the issue!!! Time’s out before you can type a message.
That is unusual Roger. I'm often very slow posting but have never had a timeout.
You obviously don’t ramble on as much as I do Steve!!!!

Is this on mobile you’re taking about it or PC?
You might be surprised. On a low-power laptop.
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xantia_v6
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Re: Airbag Testing...

Unread post by xantia_v6 »

The forum timeout for submitting a post is 2 hours...
Rhothgar
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Re: Airbag Testing...

Unread post by Rhothgar »

xantia_v6 wrote: 04 Mar 2026, 01:27 The forum timeout for submitting a post is 2 hours...
When I use my iPhone it times out in probably 5 minutes. Always has. I have to remember to select all and copy as, on a number of occasions, I’ve lost long posts when I’ve proceeded to re-enter details. Clicked back and sometimes found nothing to copy again.

It doesn’t help having a complex password that is 13 characters long with number, letters and symbols.
Last edited by Rhothgar on 04 Mar 2026, 10:26, edited 1 time in total.
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myglaren
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Re: Airbag Testing...

Unread post by myglaren »

While I wouldn't even consider doing anything of the sort on a phone, far too fiddly, maybe composing in a word processor would make life easier for you?
Rhothgar
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Re: Airbag Testing...

Unread post by Rhothgar »

myglaren wrote: 04 Mar 2026, 09:30 While I wouldn't even consider doing anything of the sort on a phone, far too fiddly, maybe composing in a word processor would make life easier for you?
I'll get my old Smith Corona XL500 stoked up with a shovel of coal, Steve...

I am more often than not remote from my PC so phone is always easier and cannot see how fast my fat thumbs can type!