Passenger seat airbag sensor? - Bimmerfest - BMW Forums



Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 5 Series > E39 (1997 - 2003)

E39 (1997 - 2003)
The BMW 5-Series (E39 chassis) was introduced in the United States as a 1997 model year car and lasted until the 2004 when the E60 chassis was released. The United States saw several variations including the 525i, 528i, 530i and 540i. -- View the E39 Wiki

Reply
 
Thread Tools Display Modes
  #1  
Old 02-23-2010, 08:52 AM
sgill sgill is offline
Officially Welcomed to the 'Fest
Location: Singapore
 
Join Date: Oct 2007
Posts: 119
Mein Auto: 328 f30 2013
Passenger seat airbag sensor?

What's the best solution to get the light on the dashboard to turn off but keep the airbags working?

I've heard / seen on the web several solutions.

Can someone please link me to the best solution on e-bay or other.

In addition, can the solution be fit in without taking out the passanger seat? I heard in some models it can and some it can not, how about the E39?

Thanks

S.G
Reply With Quote
Sponsored Links
Advertisement
 
  #2  
Old 02-23-2010, 09:40 AM
cn90 cn90 is offline
Officially Welcomed to the 'Fest
Location: Omaha NE
 
Join Date: Mar 2006
Posts: 14,995
Mein Auto: 1998 528i 5-sp 140K+
In most cars, the pass seat sensor is there to detect weight. If less than lets' say 40 lbs, the air bad does not deploy to prevent injury to a child or car seat (BTW, baby car seat should be in the back seat!).

Assuming the airbag light points to the passenger seat sensor, you have 2 options:

1. Replace the sensor (it is expensive).
http://www.bimmerboard.com/forums/posts/291770

2. Repair the diode/reistor, See post #5 carefully. It is a $10 fix:
https://www.bimmerfest.com/forums/sho...d.php?t=406087

Attached Thumbnails
Click image for larger version

Name:	e39_airbag_fix.jpg
Views:	77393
Size:	56.4 KB
ID:	219504  

Last edited by cn90; 02-23-2010 at 09:47 AM.
Reply With Quote
  #3  
Old 02-23-2010, 09:52 AM
QSilver7's Avatar
QSilver7 QSilver7 is offline
Officially Welcomed to the 'Fest
Location: Northeast Indiana
 
Join Date: Aug 2008
Posts: 11,987
Mein Auto: 2006 X5 4.4/2013 650ix GC
The airbags will still deploy. In fact...in the event of an accident...you may get more airbags deploying than what would be necessary (better safe than sorry).

The default when the SRS/airbag light is illuminated...is to deploy the bags...not to shut them all down. If there was litigation due to injury...the case would more than likely side with BMW. Their claim would be that the SRS light illuminated warning the owner that their was an issue with the system...and if they did nothing to fix the problem...BMW is not in neglect...that will fall in the lap of the owner.

If BMW designed the system to NOT deploy...then neglect and fault could fall into BMWs lap.

For example, the "normal response range"...would mean that a faulty passenger mat sensor would deploy the bag regardless if anyone is sitting in the seat or not. The "normal response range" would be...the airbag would NOT deploy if no one is sitting there:

__________________
Q {BMW CCA Member #191509}
2006 E53 X5 4.4i (Sterling Gray) 12/05 mfg date <<~>> 2013 F06 650ix Gran Coupe` (Black Sapphire) 1/13 mfg date
(SOLD)
97 740iL (Arctic Silver) <<~>> 99 540iT (Orient Blue) <<~>> 95 525IT (Alpine White)
91 735iL (Schwarz Black) <<~>> 85 325e (Bronzit)

https://www.bimmerforums.com/forum/attachment.php?attachmentid=637911&d=1538398374&thumb=1&stc=1
Reply With Quote
Sponsored Links
Advertisement
 
  #4  
Old 02-23-2010, 09:54 AM
cn90 cn90 is offline
Officially Welcomed to the 'Fest
Location: Omaha NE
 
Join Date: Mar 2006
Posts: 14,995
Mein Auto: 1998 528i 5-sp 140K+
If you byapss the sensor, then in the event of a collision, the airbag will deploy REGARDLESS if there is a passenger or not.
This BMW pass seat sensor is overdesign.
Small kids and car seat MUST be placed in the back anyway.

Another cheap fix is available for $25. Ebay search: "bmw air bag seat sensor".

"The prefabricated part substitutes for the seat mat and simulates to the seat occupancy electronics an occupied front passenger seat. Therefore the front seat passenger's air bag releases with a crash in ANY FALL, even if nobody has taken a seat on the seat."
http://cgi.ebay.com/ebaymotors/BMW-A...Q5fAccessories

FYI: My 1998 Volvo V70 has NO pass seat sensor!
Reply With Quote
  #5  
Old 02-23-2010, 12:39 PM
sgill sgill is offline
Officially Welcomed to the 'Fest
Location: Singapore
 
Join Date: Oct 2007
Posts: 119
Mein Auto: 328 f30 2013
Quote:
Originally Posted by cn90 View Post
In most cars, the pass seat sensor is there to detect weight. If less than lets' say 40 lbs, the air bad does not deploy to prevent injury to a child or car seat (BTW, baby car seat should be in the back seat!).

Assuming the airbag light points to the passenger seat sensor, you have 2 options:

1. Replace the sensor (it is expensive).
http://www.bimmerboard.com/forums/posts/291770

2. Repair the diode/reistor, See post #5 carefully. It is a $10 fix:
https://www.bimmerfest.com/forums/sho...d.php?t=406087

OK, I see the picture, but what am I supposed to do? What should I replace?
Reply With Quote
  #6  
Old 02-23-2010, 07:03 PM
cn90 cn90 is offline
Officially Welcomed to the 'Fest
Location: Omaha NE
 
Join Date: Mar 2006
Posts: 14,995
Mein Auto: 1998 528i 5-sp 140K+
I just got all the resistors, diodes etc. at my local electronics store (Radio Shack) for US $5.00.
Once I am done, I will post a DIY, so stay tuned.
Reply With Quote
  #7  
Old 02-23-2010, 07:16 PM
cn90 cn90 is offline
Officially Welcomed to the 'Fest
Location: Omaha NE
 
Join Date: Mar 2006
Posts: 14,995
Mein Auto: 1998 528i 5-sp 140K+
I'd to retract my statement above re pass side air bag, kids less than 40 lbs.

The main reason for pass side occupancy mat sensor is "cost of repair", which I disagree with because any collision that sets off the airbag is likely to result in the car being totaled. Anyway, here is the reason behind the pass side occupancy mat sensor:

http://www.sae.org/technical/papers/960226

"Due to the increasing amount of cars equipped with passenger airbags, there are now a larger number of accidents during which passenger airbags are activated although nobody is actually sitting in the passenger seat. Even when one discounts those accidents which result in car "write-offs" , the unnecessary deployment of the passenger airbag increases repair costs in an unjustified way. In order to avoid this type of situation, all BMW vehicles as of June 1994 are equipped with a seat occupancy monitoring system (SOMS installed in the passenger seat.)"
Reply With Quote
  #8  
Old 06-02-2010, 10:03 AM
cn90 cn90 is offline
Officially Welcomed to the 'Fest
Location: Omaha NE
 
Join Date: Mar 2006
Posts: 14,995
Mein Auto: 1998 528i 5-sp 140K+
So I did some more reading on pass side sensor issue. It is basically a safety issue and not a cost of repair issue:
Air Bags & Crash Sensors
http://www.aa1car.com/library/airbag01.htm


"Air bags have been in the news in recent years because of deaths that have resulted from air bag deployments in relatively minor low speed crashes. The victims have been small children or infants in the passenger seat, or small female adults drivers who were too close to the air bag or unbelted when it deployed. The deaths, in some cases, have been blamed on improper use of infant seats or not using seat belts. But others blame the deaths on government regulations that require auto makers to use air bags that deploy with sufficient force to protect an unbelted 160 lb. male adult in a 30-mph crash. This requires deployment speeds of up to 200 mph, which can cause serious injury or even death to children and small adults who are not buckled up or are too close to the bag when it deploys. In Europe, where rules allow air bags that deploy with 30% less force, there have been no deaths attributed to air bags.

The National Highway Traffic & Safety Administration (NHTSA) has reviewed their regulations and now allows auto makers to use less powerful air bags. NHTSA now allows auto makers to add switches for deactivating the air bags, and even allows consumers to have a switch installed (by a professional) to deactivate their air bags under certain circumstances. The auto makers are also developing smarter "adaptive" air bag systems that can vary their deployment speed and force depending on crash circumstances. Such systems modify air bag deployment force based on occupant size, seating position and impact speed.

For more information, see NHTSA's website information on Air Bags & air bag on-off switches

Regardless of what type of air bag system a vehicle has, though, all motorists are urged to use their seat belts, to sit as far back as possible from the steering wheel, and to put infants and children 12 and under in the back seat."



BONUS: Read the article and watch the video at the bottom of the article when some fools decided to sit on the airbag when it deployed!
Reply With Quote
  #9  
Old 07-05-2010, 06:35 AM
Orxan4ik's Avatar
Orxan4ik Orxan4ik is offline
Been there done that...
Location: Da 'Cuse, New-York
 
Join Date: Jun 2007
Posts: 1,152
Send a message via ICQ to Orxan4ik Send a message via AIM to Orxan4ik Send a message via MSN to Orxan4ik Send a message via Yahoo to Orxan4ik
Mein Auto: '97 540iA
Red face

My light just came on the other day, but before scanning and resetting it I'll be trying the eBay chip first - for $11 bucks you can't go wrong
__________________
(oOO\(|||)(|||)/OOo) /00=[][]=00\[/B]
Reply With Quote
  #10  
Old 07-05-2010, 07:47 AM
540iman's Avatar
540iman 540iman is offline
resident, old fart
Location: N.W. Indiana
 
Join Date: Sep 2008
Posts: 1,870
Mein Auto: 2002 540i sport
There is another cause of the airbag light coming on that I have not seen mentioned here. If you remove the passenger seat for any reason (say to access fuses 107-113 iirc which are hidden under the carpet below the passenger seat), you will have to remove a very fine stainless steel wire that is hooked to the seat frame itself. At the other end of this wire is a linear position sensor with a recoiler that keeps that wire tight. As the seat is moved forward, the wire unwraps or is pulled out of the linear position transducer. As the seat is moved toward the back seat, the wire is coiled back up much like a seat belt retractor. This position transducer tells the air bag system exactly where the passenger seat is relative to the air bag itself which somehow modifies which bags go off or how they go off if say the passenger is way up forward close to the glovebox. If this wire is removed at any time while power is still hooked up (battery not disconnected) you will set the airbag light and only hooking the wire back up properly to the seat frame and then doing an error reset to the airbag system will clear the light. I learned this the hard way.

Last edited by 540iman; 07-05-2010 at 07:50 AM.
Reply With Quote
  #11  
Old 07-05-2010, 08:17 AM
bluebee's Avatar
bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
 
Join Date: Mar 2008
Posts: 25,199
Mein Auto: 02 BMW 525i M54 auto 130K
Quote:
Originally Posted by cn90 View Post

http://www.aa1car.com/library/airbag01.htm

BONUS: Read the article and watch the video at the bottom of the article when some fools decided to sit on the airbag when it deployed!
Oh oh, now we're going to see big yellow warning stickers "Do not sit on air bag"!

Seriously though, since I often seat young children in the front seat, do our E39 airbags deploy with less force when they have (say 60 to 100 pounds) lighter people sitting in them?

Attached Thumbnails
Click image for larger version

Name:	airbag.gif
Views:	42544
Size:	82.4 KB
ID:	236951  
Reply With Quote
  #12  
Old 07-26-2010, 05:51 PM
Bensley Bensley is offline
Registered User
Location: Melbourne
 
Join Date: Jun 2010
Posts: 18
Mein Auto: 528i 1998
Quote:
Originally Posted by 540iman View Post
There is another cause of the airbag light coming on that I have not seen mentioned here. If you remove the passenger seat for any reason (say to access fuses 107-113 iirc which are hidden under the carpet below the passenger seat), you will have to remove a very fine stainless steel wire that is hooked to the seat frame itself. At the other end of this wire is a linear position sensor with a recoiler that keeps that wire tight. As the seat is moved forward, the wire unwraps or is pulled out of the linear position transducer. As the seat is moved toward the back seat, the wire is coiled back up much like a seat belt retractor. This position transducer tells the air bag system exactly where the passenger seat is relative to the air bag itself which somehow modifies which bags go off or how they go off if say the passenger is way up forward close to the glovebox. If this wire is removed at any time while power is still hooked up (battery not disconnected) you will set the airbag light and only hooking the wire back up properly to the seat frame and then doing an error reset to the airbag system will clear the light. I learned this the hard way.
How do you do the error reset?
Reply With Quote
  #13  
Old 07-26-2010, 06:04 PM
540iman's Avatar
540iman 540iman is offline
resident, old fart
Location: N.W. Indiana
 
Join Date: Sep 2008
Posts: 1,870
Mein Auto: 2002 540i sport
Just as you would any air bag system fault...you restore the system to operational (in this case reattach the wire to seat and move it full back and forth) and then you use a Peake air bag reader or similar and hit "clear error"
Reply With Quote
  #14  
Old 07-26-2010, 08:15 PM
bmw7833's Avatar
bmw7833 bmw7833 is offline
Officially Welcomed to the 'Fest
Location: Malaysia
 
Join Date: Sep 2007
Posts: 232
Mein Auto: Year 1997 E39 M52B25
Subscribed!
__________________
Live the e39..!!

Reply With Quote
  #15  
Old 09-15-2014, 05:21 PM
y2k_o__o y2k_o__o is offline
Registered User
Location: Canada
 
Join Date: Jan 2014
Posts: 13
Mein Auto: z4
Quote:
Originally Posted by cn90 View Post
In most cars, the pass seat sensor is there to detect weight. If less than lets' say 40 lbs, the air bad does not deploy to prevent injury to a child or car seat (BTW, baby car seat should be in the back seat!).

Assuming the airbag light points to the passenger seat sensor, you have 2 options:

1. Replace the sensor (it is expensive).
http://www.bimmerboard.com/forums/posts/291770

2. Repair the diode/reistor, See post #5 carefully. It is a $10 fix:
https://www.bimmerfest.com/forums/sho...d.php?t=406087

My 03 Z4 airbag light came on too
I came across with this diode repair

Just a simple diode replacement? What's the spec for the diode?

When I clicked at the link, I didn't see anything at #5

Please shed me some light as the SRS light is getting annoying at the dash

Thanks!
Reply With Quote
  #16  
Old 12-05-2015, 02:11 PM
Professor19 Professor19 is offline
Registered User
Location: Tampa, FL
 
Join Date: Jun 2015
Posts: 9
Mein Auto: BMW 328i
Cheap fix

Is there a DIY on this topic that can be easily located? Any info is appreciated!!
Reply With Quote
Reply

See More Related BMW Stories


Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 5 Series > E39 (1997 - 2003)
Today's Posts Search
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On



Forum Jump


All times are GMT -7. The time now is 04:51 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
© 2001- VerticalScope Inc. All rights reserved.