Discussion
I had a passenger restraint warning in my 7 series this week. Took it in and it turns out i need a £450 sensor mat in the drivers seat. However the car is fine to drive and the air bag will activate in an accident "the engineer said of course it will activate on the drivers side the car can't drive itself can it?" was what the receptionist told me. So if everything works without this sensor WTF do i need it. Open floor to the sensor mat educated.
S70JPS said:
I had a passenger restraint warning in my 7 series this week. Took it in and it turns out i need a £450 sensor mat in the drivers seat. However the car is fine to drive and the air bag will activate in an accident "the engineer said of course it will activate on the drivers side the car can't drive itself can it?" was what the receptionist told me. So if everything works without this sensor WTF do i need it. Open floor to the sensor mat educated.
The sensor is to tell you if there is someone in the seat who isn't wearing their seatbelt. Presumably it's not working any more, so it thinks that you're always not wearing it.steve6304 said:
if the airbag warning light is on, the ENTIRE system is deativated...
nope, it'll depend on the level of the fault.In this case, it'll fire both driver and passenger airbags in an accident, regardless of if someone is in the seat.
The sensor mat is to save the price of a dashboard and airbag in an accident and only fire it if needed.
Without being sure that someone is in the seat, it'll fire both just in case.
You can often fit bypass boxes onto the connector instead, although it's a struggle to find out if they emulate an empty or full seat.
Meoricin said:
The sensor is to tell you if there is someone in the seat who isn't wearing their seatbelt. Presumably it's not working any more, so it thinks that you're always not wearing it.
If it was that simple then you could work around it by fastening the seat belt. I suspect there's more to it than that though!Bear in mind if the system doesn't appear (from the warning light) to function properly on start-up then it'll fail MOT next year.
There's a sensor mat which has a resistance for occupied and unoccupied.
The problem is from either the mat breaking a connection inside, or more commonly the wires to the mat that are under the seat.
When it sees it as open circuit, it'll light the warning.
http://www.ebay.co.uk/itm/BMW-PASSENGER-AIRBAG-SEA...
There's an example of the bypass, they are usually two resistors and a diode inside, but it is likely it always gives a "seat empty" signal.
The problem is from either the mat breaking a connection inside, or more commonly the wires to the mat that are under the seat.
When it sees it as open circuit, it'll light the warning.
http://www.ebay.co.uk/itm/BMW-PASSENGER-AIRBAG-SEA...
There's an example of the bypass, they are usually two resistors and a diode inside, but it is likely it always gives a "seat empty" signal.
TheEnd said:
nope, it'll depend on the level of the fault.
In this case, it'll fire both driver and passenger airbags in an accident, regardless of if someone is in the seat.
The sensor mat is to save the price of a dashboard and airbag in an accident and only fire it if needed.
Without being sure that someone is in the seat, it'll fire both just in case.
You can often fit bypass boxes onto the connector instead, although it's a struggle to find out if they emulate an empty or full seat.
If it's anything like an e46 then it can be reprogrammed in about 1 min and a bit removes from under the seat in about 10 seconds. My local indie did this for nothing. In this case, it'll fire both driver and passenger airbags in an accident, regardless of if someone is in the seat.
The sensor mat is to save the price of a dashboard and airbag in an accident and only fire it if needed.
Without being sure that someone is in the seat, it'll fire both just in case.
You can often fit bypass boxes onto the connector instead, although it's a struggle to find out if they emulate an empty or full seat.
As TheEnd writes above the airbag will still go off if re-programmed right. The sensor works by sensing whether there is an occupant and if there is none it will not deploy the airbag. You can set the system so that it thinks there is always an occupant so the airbag will always go off if triggered by a prang.
S70JPS said:
Paid £420 for a new mat. I've had one massive bang (not my fault) where the airbag saved my life. Can't be too careful!
How old was the car? Had an airbag lamp fault on my Merc when it was 5yrs old due to the clockspring in the steering column and the dealer said as it was safety related MB would cover it under goodwill - although the car was on a maintenance contract until it was 6yrs old so I presume I wouldn't have had to pay anyway.Gassing Station | BMW General | Top of Page | What's New | My Stuff