Possibly Solved! Airbag Light w/ Aftermarket Seats

[Shipkiller]

According to the WDS and other documentation, the airbag will fire at all times unless it is turned off by the KEY.

What the mat provides is a way to moderate the force of the upper passenger airbag deployment. If the mat is OOC, then the airbag fires at full force.

I cannot believe that in this lawsuit happy country we live in, ANYONE would believe that BMW would be that 'monumentally stupid' as to automatically deactivate an airbag because of a fault in another part of the SRS system.

I have only heard of ONE instance that a BMW airbag has not deployed and that airbag was 14 years old. Airbags only have a service life of 10 years.

[amoore12]

I am very interested in the possible solution. My Z4 was made in 04/2004. The airbag light came on so I bought Autoenginuity which turned the light off (code 20 pass seat occupancy sensor) and it stayed off. I recently purchased a set of leather seats from a 2004 Z4 (manufactured in 10/2003). When I installed them the airbag light came back on. Same error 20 as before. Autoenginuity would not reset the light. It would cycle but came back on immediately. As a test I put the original passenger seat back in and tried to reset the light. It would not reset. Very odd. Did something with the replacement seat cause an issue? I understand there is a difference in the sensor from 2003 to 2004 but both passenger seats have the same small box in the rear of the seat, plus according to realoem.com 10/2003 was the cutover date and the new seat should have the same setup as my original seat. I am wondering if something shorted in the system or if something else is wrong as two seats both showing error 20 does not make sense. Too much of a coincidence. Battery was disconnected during all seat swaps. Any suggestions?

[pokeybritches]

As you said, the sensor is different in the 04+ models. I know some have retrofitted 2004+ seats in a 2003, but I haven't read of anyone going the other way. Maybe you can check some of the retrofit threads for ideas. What is the full description of code 20?

[amoore12]

I found an alternate solution if the contributors in this thread cannot get their solution working. It doesnt let you disable like would be desired, but the darn light would go away (after a reset) and the Z4 is listed. Check it out... http://www.bimtronics.com/

[amoore12]

All I can find for the error 20 is that it is the Occupancy Sensor in the passenger seat, so one would have to assume the mat. Any time I enquire to those that would really know they say to have it hooked up to the BMW GT1 diagnostic computer. The local BMW dealer wants $150 just too hook up the car and tell you what it says plus whatever it costs to fix it and they dont even credit the diagnostic fee if you move forward with the repair. While I would prefer to fix it correctly, I have a hard time justifying the fee. I may head down that path eventually, but I like the idea of the bimtronics gizmo I found. Wish I knew someone with the GT1 :-) Thought about buying one. If you have to use it 3 or 4 times it would pay for itself.

[pokeybritches]

Good lord, for that price I'd finish one for the M in a heartbeat.

[iPhoneEngineer]

So I've read on the forum that it's possible to get an SRS light from replacing the driver's seat alone (no occupancy sensor), and some have attributed it to the pyrotechnic seatbelt pretensioner.

Anyone have details on this and how to ensure it is avoided, + the pretensioner continues to work?

[Shipkiller]

Originally Posted by iPhoneEngineer

So I've read on the forum that it's possible to get an SRS light from replacing the driver's seat alone (no occupancy sensor), and some have attributed it to the pyrotechnic seatbelt pretensioner.

Anyone have details on this and how to ensure it is avoided, + the pretensioner continues to work?

If the SRS system does not see the seat belt tensioner or the seat occupancy sensor, it WILL trigger a SRS Airbag light. There is a way on the E46 to bypass the seat occupancy sensor using two resisters but I have not heard if that works on the E85/86.

[ZStig]

seems like everyone just gave up :/

[Shipkiller]

The real issue is that you need special equipment to reset the SRS Airbag light.

I can do this (reset the light) but I don't have the need to swap out seats yet so I don't want to bother.

[ANUSTART]

Originally Posted by Roffle Waffle

seems like everyone just gave up :/

I'm taking on the occupancy sensor/mat this winter/early spring. The wife won't be riding with me over the winter so it's no rush. I'm going to revisit this with photos an text when I finally get to it.

The seat swap is frustrating though. Factory seats on the base model could be used to coerce a confession from a mafia hitman. Never plan to go back to those things.

[3002 tii]

Any update to this?

Found this on the other forum which shows the difference in the sensors between pre and post-facelift Z4s. I'm getting closer to throwing in bucket seats but ideally prefer not having to transplant or (buy a new new sensor) and install inside the aftermarket seat.

http://www.z4-forum.com/forum/viewto...=23646#p331649

[AK72]

Hello everyone, I installed Recaro Sportster seats in my Z4M and now I need help with the airbag light. Has anyone found solutions for this issue?

[maupineda]

Did you keep the pretensioner? Or ditched it?

[AK72]

Originally Posted by maupineda

Did you keep the pretensioner? Or ditched it?

pretensioners are still in place, the only thing missing is the occupancy mat/sensor

[Piper1]

Originally Posted by AK72

pretensioners are still in place, the only thing missing is the occupancy mat/sensor

I replied in your other post but I grabbed a mat before they got discontinued and put it under my sparco cushion when you could get just the mat. You can get an emulator or pillage a mat from a doner seat.

[AK72]

Problem solved, got occupancy mat from 2009 x5 sport seats, same interface as in our cars

[maupineda]

Great contribution!!!