[davemoz]

Airbag light and passenger disabled fault - fixed!

Ok so I have taken my time and worked methodically through the problem, the previous content in the thread will give the overview. After scouring the web it was the Berlingo forum that gave me the clue to the fix.

All of the wiring diagrams I found on the peugeot service website only showed the airbag, rain sensor and comm2000 ecu's on the +VAN1 network. After reading the Berlingo forum it is clear that a VAN fault on the BM34 engine fuse box causes the problem that I had.

After pulling the BSI out and checking the wiring it is clear the BM34 is connected to pin 6 & 8 on the black 40 pin connector in the BSI but is joined in the loom with the comm 200 unit. So there are 4 ECU's connected to +VAN1 the engine fuse box, airbag, rain sensor and comm2000 unit. The airbag connects on pins 28 & 30 and the rain sensor on pins 38 & 40 on the white 40 pin plug all of thes pins are joined together on the BSI PCB to the respective VAN lines.

So after investigation I found that each ECU connected to the VAN has an 8K resistance, so with the BSI disconnected I checked the wiring and only found 8K on pins 6 & 8 on the Black BSI connector, after checking the engine fuse module on the 10 pin black connector (the blue and red wire) pins 6 & 10 I found slight corrosion on pin 10. After cleaning and reconnecting the BSI the total network resistance with all 4 ECU's connected was exactly 2K ohms which previously when measured was 2.67K ohms.

So the sad part is that all of the hours spent pulling the BSI and wiring apart turned out to be a dirty/slightly corroded pin on the engine fuse module! It appears that the BSI firmware obviously is sensitive to corrupted packets on the VAN as no other faults were reported, maybe the PP2000 software would have picked this up but the independent only reported the airbag not communicating not the BM34!

Anyway I put this fix up as I hate it when people fix things and do not contribute their findings which happens regularly across all forums! I hope I have saved future members time and money by posting this reply.

Hi,
I realise this is an old post but do you remember what the VAN resistance was on the BSI alone with nothing connected? I assume it would be open or high impedance going by your post?

Thanks