Fixed my airbag light problem after seat upgrade

[jimmy2cows]

After recently upgrading from manual leather to memory electric leather seats, the passenger airbag light came on whenever the seat was occupied.

Some digging suggested one seat (new or old, depending on the fault) might have an occupancy sensor while the other seat did not. I wasn't seeing any codes on my generic code reader, so left it until I knew what was going on.
And didn't drive the car with anyone in the passenger seat in case an airbag wouldn't work if needed. Unlikely to crash, but better to not chance it.

My tech2 arrived today so I thought I'd have a play. Airbag module reported U2050 - SOD circuit high voltage. Looking at the variant config, the seat occupancy settings showed as not configured. And since the airbag ecu is locked there's no way to change that.

So there must be a difference in the seat innards. I checked the plug where it connects to the body. Both old and new seats have the same connections, pins in the same position.

So then I gave in to the inevitable and started dismantling the old seat, to see what is or isn't in there.
At the back of the seat base I found a grey box that I assume is the child-seat transponder, and a plug that wasn't connected to anything:


Tracing the wires and comparing to the wiring diagram, this is the plug for the occupancy detector mat.
Back to the new seat, I took undid all the clips and stuff in holding the seat back trim in place to get at the wiring in the back of the seat base. That is not fun when the seat is in the car I can tell you.
In the new seat, the occupancy detector is plugged in:


Bingo!!

Unplugged it, sat in the passenger seat and switched on the engine. No airbag light.
Quick check on tech2 again and once the original dtc was cleared it didn't come back. No fault codes reported from the airbag module so I don't think disconnecting the detector messed up anything else.
So I guess that's sorted.

I'm thinking the problem is like this:
Car came out of the factory without a passenger seat occupancy detector. Airbag ECU isn't expecting one, so not configured to use it.
Put in a seat with occupancy detector and suddenly the airbag ECU is seeing something it doesn't know how to deal with, so puts on the airbag light to complain.
Disconnect the occupancy sensor and the airbag ECU is happy again, because everything now seems as it was with the old seat.

[simon1]

Lol I've just done this today
had ditchs Sri leather seats of him meet up at spellys last wk to swop seats
then the same fault codes my seats have OCD sensor Sri ones didn't
been bk to strip my old seat to get the OCD out
mine has a large computer block on it too from the cable as multi stage
vx wanted £230 for OCDsensor
And what a ball ache stripping seat down still need to strip my Sri leather seat and retro fit seat sensor
as at the moment it's on the back floor plugged in to loom to stop light from coming on nxt job to do

[jimmy2cows]

Looks like i got it the lucky way round lol. Did not fancy stripping the internals out of my old seats.
The jobs just never end eh

[snake-man]

can you tell me what plug it is so i can do mine thanks

[Robsey]

From the two images above, it looks like the grey connector with the following 3 wires.
(Grey plug on left in first image, grey plug on right in second image).
1 - Brown / Yellow
2 - Black / Yellow
3 - Blue / Yellow.

[snake-man]

thanks i unpluged it and now the light is off but will the air bags still go off in a crash ???

[eusadi]

Hello, thank you very much for your information, it has helped me a lot, I changed the seats like you and I had the same problem, it was unplugging the connector and it does not turn on the light, greetings from Valencia, Spain.

[ivan_kv]

Is the airbag still working after unplug that sensor from seat?

[eusadi]

Yes, without problem

Is the airbag still working after unplug that sensor from seat?

Enviado desde mi SM-G965F mediante Tapatalk

[Prince21]

Old post I know I’m having same problem as you guys passenger seat and need it it sorting is it easy enough to strip seat back etc to get at the plug