Occupancy Sensor and SRS Light

[tonycajjo]

did anything have to be reset after everything was replaced. i want to remove my seat to see whats going on under there with the previous owners dvd installiation. In my freinds acura when we removed the seat we had to go to his shop, hook up to the computer to re-enable the air bags. does this not apply to the X5?

ADDED:
nevermind, found that if i remove the battery prior to disconnecting anything i should be fine.

(p.s. i did search for seat removal but found nothing, then i searched for airbag info again and found what i was lookin for.)

[elric75]

Just had my airbag light start coming on Sunday in my 2000 E53. Guess I'll have to have the dealer check this mat sensor out - luckily I'm still in my extended warranty.

Sounds like yet another "wear item" E53 owners should know about.

[David.X5]

Great Thread! Worked through this and solved my problem.

I have a 2001 X5 4.4i with the Sport Package.

I had the problem with the airbag light coming on related to the sensor mat - it would be off right when I started the car but would light up after a few seconds (this is good actually, as I have read that it will reset itself when you replace the sensor). The problem was usually during or right after having an adult passenger. After a day or two with the seat empty, the light would go off. I have the Autoenguity software with the BMW extensions - it reported a (hex) error 1A "Seat Occupancy Detector, Passenger, Coding Data".

I decided to replace both the sensor mat and under-seat control module - I was happy about that, as I broke the brittle plastic of the control module during dissassembly.

For my seats (don't know the year ranges or option ranges this covers), I was told I these are the part numbers (below). The prices shown are from getbmwparts.com in USA. These are not the cheapest versions shown in the parts lists (I checked BMW South Atlanta website first) but I don't have access to VIN specific part searching like the pros do. These did fit physically and cleared the errors.

65776921952 SENSOR MAT $125.37
65776940191 CONTROL $63.48

The tools you want to install the "clips" are called "hog ring pliers" and can be bought from amazon or an upholstery supply. For the rings with the worst access, I used a pair of Crescent X2 long reach pliers (about a foot from the handle to the tips - they use two pivots).

The "clips" are conventional upholstery hog rings and normally cost about 5 cents each. I needed 15 for one seat. I simply cut them off rather than trying to wrestle them off. I was careful to fish the both broken pieces out so they didn't float around and cut the seat or the wiring later. You will need sturdy side cutters to cut the hog rings.

The only step I struggled with is related to "Figure 15" - you have to remove a long rectangular metal bracket that runs along the back of the seat, roughly from one hinge to the other. You should approach it facing the seat from the rear and look in the hinge area - there are two screws on each end of the bracket - one will be visible on each end, but you have to push the leather up with your fingers to expose the other screw. They are pan head screws that require a Torx bit.

I did not unplug the battery as the whole seat assembly uses a single connector and the work is done out of the car on the de-energized seat. I did turn the car off and removed the key from the ignition before unplugging the seat harness.

After I re-installed the seat and started the car, the light stayed off. No coding or light clearing required (for me). As I said before, I read somewhere that you should check the behavior of the warning light before trying this - if it is off when you start the car and then comes on after a few seconds, it apparently will clear itself when the offending part is replaced.

BTW, while I had the seat out of the car, I got color matched dye and cleaning kit from LeatherWorldTech.com and thoroughly cleaned and re-dyed the leather. It looks great now. You do need to know your interior color code as they have dye to match some/most colors.

I also "patched" a worn spot in the foam on the seat bolster with a new piece of foam to get its stiffness back to new. Might as well...

[Lamby]

Thrasher is the man! My SRS light is on, so I found the fault, its the Mat, I need to change the sensor out as I checked everything and found that even unplugging the sensor and a bit of WD40 in the connections and a bit of a clean up didnt really work. So the seat has to come out. Thanks to this write up I will only have to pay for parts rather than my bloody expensive garage bills.

[andrewwynn]

You can replace sensor with a faker plug. About $10.

The trade off is the car sees a person always so I believe to have to keep seatbelt plugged and in case of Accident the passenger air bags will activate.

My wife's passenger butt sensor is flakey. It doesn't see a butt when it's cold out. We drive ten minutes I can stop and start the engine it will reset the airbag light (once cabin is warm).

I actually have a spare seat bottom but it's the wrong color and I think the pad and heater are sewn into the seat so you can't swap just the sensor pad (correct me if I'm wrong). If the sensor pad gets worse I'm planning to just get the cheater plug that "looks like" a pad to the brain and teach wife to plug in passenger seat belt when empty


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[Overboost]

Any downside to just deselecting the seat occupancy recognition in BMW Scanner 1.4?

[andrewwynn]

The problem is: will the airbag go off if needed? If you can confirm yes, will it go off half force/full force? I would bet on yes that it would be designed to err toward bag activating always if crash and no sensor (probably even if airbag light on) but I wouldn't use software to disable unless I knew it worked


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[Overboost]

Originally Posted by andrewwynn

The problem is: will the airbag go off if needed? If you can confirm yes, will it go off half force/full force? I would bet on yes that it would be designed to err toward bag activating always if crash and no sensor (probably even if airbag light on) but I wouldn't use software to disable unless I knew it worked


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I would guess it is only the occupancy recognition disabled but would still activate but I do not have a definitive answer for you.

[Qsilver7]

Originally Posted by andrewwynn

The problem is: will the airbag go off if needed? If you can confirm yes, will it go off half force/full force? I would bet on yes that it would be designed to err toward bag activating always if crash and no sensor (probably even if airbag light on) but I wouldn't use software to disable unless I knew it worked


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It is designed to err in the favor of caution...see text highlighted in yellow in info below about the various "thresholds" of the MRS/SRS system:

[white46]

I would just plug in the occupancy mat bypass emulator and clear SRS.
Emulator can be bought from ebay for as little as $10.