Citroen Picasso B78 Lexia needed.. Airbag light

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

User avatar
GiveMeABreak
Forum Admin Team
Posts: 29046
Joined: 15 Sep 2015, 19:38
x 3614

Re: Citroen Picasso B78 Lexia needed.. Airbag light

Post by GiveMeABreak »

With the Airbag lights on it won't pass the MOT, so is not roadworthy - so the warranty company cant ignore it.

James if you have the trace from the session (in the reports menu) - you should be able to print it off / save as a PDF or print to PDF if you have a PDF writer installed, then you can email it to Matt - that will look a bit more official.
Itchigo55
Posts: 17
Joined: 21 Jun 2019, 12:24
x 1

Re: Citroen Picasso B78 Lexia needed.. Airbag light

Post by Itchigo55 »

Sorry all, had a nightmare last few days. My Mini chewed its crank shaft pulley up and had to be towed away :(

Huge thank you to James for taking the time to scan my car, funnily enough since he touched the wires under the seat the airbag light hasn't been on again!! I had taken it to a garage for another full scan as the dealer I brought it from agreed he would refund me the costs. The mechanic did comment about how many fault codes came up, has anyone else had a C4P B78 scanned and gets a few errors on Lexia etc but no warnings on the dash? My wife took the car and didnt get the exact codes that came up, Im going to take it back and get the exact codes that James couldn't read next week.

I've brought some contact cleaner, I'm going to power down the car and then disconnect and reconnect the under seat cables this weekend.

My greatest fear is that the airbag warning crops back up just before we're involved in a crash, so Id like it sorted. Apart from that everything else is all good, I could be becoming a french car convert (Maps are abit of a pain to update FYI though requiring a code.)

208 GTi could be on the cards to replace my Mini.
User avatar
GiveMeABreak
Forum Admin Team
Posts: 29046
Joined: 15 Sep 2015, 19:38
x 3614

Re: Citroen Picasso B78 Lexia needed.. Airbag light

Post by GiveMeABreak »

Dash display warnings are only indicated for things you need to know about there and then. There are a million things going on under the bonnet and the Engine ECU and BSI only store faults depending on type, severity, whether intermittent or permanent and only the ones that are likely to affect engine performance or emissions are going to flag up an Engine Management Light on the dash.

It is common for errors to be recorded and stored for technicians to gauge the history of faults to aid in diagnosis. Some faults self-clear when the conditions are satisfactory for the fault to disappear. Such is the 'magic' (or not) of modern cars - they can correct and compensate for some levels of faults and have operating tolerances depending on driving conditions, environment etc.

So it looks like you had the common airbag connection wiring issue - and cleaning the contacts up and ensuring the connections are sound should sort it. The Airbag systems self-checks at startup and runs a diagnostic. If all components report ok, then the airbag warning light self-extinguishes. If a fault occurs at any time during driving, it will flag a warning up straight away.
Hell Razor5543
Donor 2021
Posts: 12590
Joined: 01 Apr 2012, 09:47
x 1726

Re: Citroen Picasso B78 Lexia needed.. Airbag light

Post by Hell Razor5543 »

One thing that came to my mind later was that, with all of the parking sensor faults AND the ones for the motorised tailgate, maybe she had been involved in a tail end shunt that (when it had been repaired) had not had the errors cleared (they remained cleared when we re-ran the global diagnostics after a short run).
Itchigo55
Posts: 17
Joined: 21 Jun 2019, 12:24
x 1

Re: Citroen Picasso B78 Lexia needed.. Airbag light

Post by Itchigo55 »

Could be something to check, I'll see if I can get it up on the ramp and see if there's signs of a shunt.
arkay99
Posts: 2
Joined: 31 Jan 2022, 21:38

Re: Citroen Picasso B78 Lexia needed.. Airbag light

Post by arkay99 »

Hi, new to the forum.
Have a C4 Grand Picasso 2014 (1.6e-HDi VIN VF7**************[VIN obfuscated, can be read by forum staff]). The MoT is coming up and the dreaded Airbag pre-tensioner fault display on startup. I suspect this is the loom. Looking back on my records I think the dealer found this Sep 2020 ("Investigate Air Bag light on dash, found loom under seat needs repair") but I went to a non-dealer, who seemed to have managed to clear the light - at least enough to get it past the last MOT. From what I've read in this forum I've come to the conclusion the wiring is a common problem.
I did try to use a cheap couple of ELM OBD2 readers to "read the fault code". They did actually work for the engine sensors, but failed to display anything else. Having now read on the forum a bit more about Lexia/Diagbox etc I know I'm not going to get the info from these cheap readers (I might keep them tho for the engine readings, they were £15).
Long ramble to my actual question. Can I ask the dealer for the full Lexia output (I'd be interested to see what other faults are logged) ?
How much do you think I should pay for the loom repair and does anyone recommend any dealers in the S.W London area? My closest are Robins and Day Walton on Thames and the West London Chiswick one nr M4. I dont mind paying to fix properly I just dont want to be ripped off.

Thanks!
User avatar
GiveMeABreak
Forum Admin Team
Posts: 29046
Joined: 15 Sep 2015, 19:38
x 3614

Re: Citroen Picasso B78 Lexia needed.. Airbag light

Post by GiveMeABreak »

The dealers have pretty much standard rates. Give them a ring and tell them it has been previously diagnosed as a loom repair and get a quote. Shouldn't be more than an hour to do.
arkay99
Posts: 2
Joined: 31 Jan 2022, 21:38

Re: Citroen Picasso B78 Lexia needed.. Airbag light

Post by arkay99 »

Thanks, will do.