NVADER 54 Report post Posted December 31, 2013 Problem solved...I think. To get a consistent and reliable reading off the wheel speed sensor's, I had to hook the multimeter up in parallel with the ACS/DSC control unit, with the car on, and the meter set to 2V. Then spinning the wheel by hand gave me a reading between .4 and 1.5V on all sensors except the front right. (Putting this info on here because it's bloody hard to find).Anyway, new sensor is definitely faulty or for a different model as it throws crazy readings back at me. So after all that, I just have to get hold of another sensor and the problem will probably be solved. Quote Share this post Link to post Share on other sites
Phil-540i 166 Report post Posted December 31, 2013 Kool process on your fault-finding - well done............. Quote Share this post Link to post Share on other sites
antil33t 90 Report post Posted January 2, 2014 (edited) Nup. That's from Deutsche Parts USA and came recommended by my auto sparky. Happy to be corrected if anyone knows better but from what I was told, all those seat sensors do is tell the passenger airbag whether to deploy or not after sufficient impact. The bypass just removes the sensor from the equation and keeps them active all the time. Like I said, if I have a decent enough accident, the more bags the better A 10c diode, and two 10c resistors. - It's also Illegal to do this. I would have not as a professional ever tell anyone to do this. Edited January 2, 2014 by antil33t 1 Quote Share this post Link to post Share on other sites
NVADER 54 Report post Posted January 2, 2014 A 10c diode, and two 10c resistors. - It's also Illegal to do this. I would have not as a professional ever tell anyone to do this. Interesting...I haven't actually done this yet because the airbag light has stopped coming on now but I can't see why it would be an issue? The whole system is still operational and as long as it's done cleanly, no wof inspector is going to notice it, much less make a fuss over it. I'll be getting an LVVC at some point for the wheels and lowering springs anyway so can get it added to the plate then but I don't see it causing any problems in the meantime. Quote Share this post Link to post Share on other sites
hotwire 352 Report post Posted January 3, 2014 A 10c diode, and two 10c resistors. - It's also Illegal to do this. I would have not as a professional ever tell anyone to do this. Exactly, it is illegal & no professional person should be quoting this repair - full stop! Interesting...I haven't actually done this yet because the airbag light has stopped coming on now but I can't see why it would be an issue? The whole system is still operational and as long as it's done cleanly, no wof inspector is going to notice it, much less make a fuss over it. I'll be getting an LVVC at some point for the wheels and lowering springs anyway so can get it added to the plate then but I don't see it causing any problems in the meantime. The theory is as you say BUT - there is no guarantee it is going to work as intended. Frankly its a pity the WOF inspector cannot identify this mod. 1 Quote Share this post Link to post Share on other sites
NVADER 54 Report post Posted January 3, 2014 (edited) Exactly, it is illegal & no professional person should be quoting this repair - full stop! The theory is as you say BUT - there is no guarantee it is going to work as intended. Frankly its a pity the WOF inspector cannot identify this mod. Firstly, nobody has quoted the job. I can understand completely that no auto sparky would carry out the job during business hours. That's not the point. It's a fairly common procedure as the mat sensor's are not really necessary and ridiculously expensive to replace. I don't see how bypassing an 18 year old sensor from an 18 year old airbag system is going to make it any less reliable. It's not a theory. This does not affect the performance of the airbags at all, and if the system is not operational, it will throw an SRS fault. There's no guarantee that 18 year old airbags will deploy as intended anyway. I'm not sure why people keep bringing this up to be honest. This is a project car and an old one at that. It will get a warrant with a mat sensor bypass; or it won't. If the wof inspector does pick up on the 2cm long piece of plastic under the seat and is worried about it, I'll pull all the airbags out and get them to note it on the cert tag - which is completely legal. I'm actually not at all phased either way because I'm intending to swap the dash out. Edited January 3, 2014 by NVADER Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted January 4, 2014 just as a side note, airbags dont always just go off. many read the weight of the ocupant and for lighter people blow with a smaller charge than if a big person is in there. fixing the seat doesnt cost much, just do it 1 Quote Share this post Link to post Share on other sites
NVADER 54 Report post Posted January 4, 2014 just as a side note, airbags dont always just go off. many read the weight of the ocupant and for lighter people blow with a smaller charge than if a big person is in there. fixing the seat doesnt cost much, just do it "I'm not sure why people keep bringing this up to be honest. This is a project car and an old one at that. It will get a warrant with a mat sensor bypass; or it won't. If the wof inspector does pick up on the 2cm long piece of plastic under the seat and is worried about it, I'll pull all the airbags out and get them to note it on the cert tag - which is completely legal. I'm actually not at all phased either way because I'm intending to swap the dash out." People - this is a project thread, not a thread about the merits of repairing an 18 year old airbag sensor. If you disagree with what I'm doing, read a different thread It's a commonly performed mod that is ridiculously simple and just as reliable as replacing the mat sensor with an aftermarket item. Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted January 4, 2014 just as a side note, airbags dont always just go off. many read the weight of the ocupant and for lighter people blow with a smaller charge than if a big person is in there. fixing the seat doesnt cost much, just do it Really ??? how does this so called weight measuring sensor work ? 2 Quote Share this post Link to post Share on other sites
hotwire 352 Report post Posted January 4, 2014 "I'm not sure why people keep bringing this up to be honest. This is a project car and an old one at that. It will get a warrant with a mat sensor bypass; or it won't. If the wof inspector does pick up on the 2cm long piece of plastic under the seat and is worried about it, I'll pull all the airbags out and get them to note it on the cert tag - which is completely legal. I'm actually not at all phased either way because I'm intending to swap the dash out." People - this is a project thread, not a thread about the merits of repairing an 18 year old airbag sensor. If you disagree with what I'm doing, read a different thread It's a commonly performed mod that is ridiculously simple and just as reliable as replacing the mat sensor with an aftermarket item. Maybe it keeps coming up cause it's ILLEGAL. You seem to be an authority on this system - I guess you know auto electrics better than me. Regardless of the age of a the car - if it has the system - by law it must operate as per OEM spec. Yes, you can remove the system & get it certified BUT you must remove the entire system. As for weight sensing - more that it will ignore up to a certain weight before deploying & hence a vaguery of a bypass module actually operating. Quote Share this post Link to post Share on other sites
Phil-540i 166 Report post Posted January 4, 2014 (edited) Personally, I think the point has been made, & the owner seems to have a realistic understanding on where he wants to go in the future with his air-bags in this vehicle......and I think he's spelled that out very clearly............ Edit - I'd love to see pics with the new rims............. Edited January 4, 2014 by Blue-540i Quote Share this post Link to post Share on other sites
NVADER 54 Report post Posted January 4, 2014 (edited) Sorry; at what point did I ask for comments regarding the legality of this? And at what point did I claim to be an authority on srs systems? Maybe I'm building an ornament for my great aunt's brother's uncle's back yard that doesn't need to be legal? What I do know, is that these bypass units are commonly used and emulate an occupancy sensor-less system which is just as effective as replacing the mat sensor. There's nothing vague about it. The occupancy sensors (when working) detect anything over 18kg. The bypass removes the on/off functionality in favor of an always-on set up. It doesn't allow the system to be made inoperable, nor does it affect the the performance of the airbags, therefore any wof inspector with half a grain of common sense should have no issue with it at all; and as I've said before, if they do have an issue, ill pull both the bags out and add it to the cert. I've stated my purpose and goals. If you're committed to having a cry about airbags you're more than welcome to start your own thread. There are that many articles/videos about bypassing mat sensors that it's actually hard to find information about replacing the unit. If it was your car, you could replace the sensor. I'm not going to - end of story. It will cost me less to pull out two airbags than it will to replace a mat sensor. Tires should arrive next week so will post pics then Edited January 6, 2014 by NVADER 1 Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2132 Report post Posted January 4, 2014 Wasn't goin to participate, but wouldn't it be cheaper to replace the mat than re-certify the car? And when all said and done, an LVV cert plate isn't going to help save you or more importantly your passengers/partners etc that are in the at or driving it 1 Quote Share this post Link to post Share on other sites
NVADER 54 Report post Posted January 4, 2014 Ill be getting a cert for wheels and lowering springs anyway so it wouldn't cost me any more. That's also a worst case scenario. Pretty sure that it'll get a legitimate warrant with the bypass installed. I'm not convinced 18 year old airbags will do anything to help save anyone regardless. Sent from my SM-N9005 using Tapatalk Quote Share this post Link to post Share on other sites
KwS 2424 Report post Posted January 4, 2014 Ill be getting a cert for wheels and lowering springs anyway May i ask, why? Quote Share this post Link to post Share on other sites
NZ BMW 368 Report post Posted January 4, 2014 You could just buy a new sensor and install it: http://www.ebay.com/itm/BMW-E38-E39-SEAT-AIR-BAG-MAT-SENSOR-528i-530-540i-M5-730-740il-750il-8367593-/171024394215 A lot of the US based forums seen to suggest that it's an easy DIY for someone who is handy with tools etc. Quote Share this post Link to post Share on other sites
NVADER 54 Report post Posted January 4, 2014 May i ask, why? Because the wheels are bigger than factory spec and because it's being lowered. Technically that means neither are 'sole' modifications. I've had some hassles with warrants (and roadside police checks) in the past so it's just easier to get them certed and be done with it Quote Share this post Link to post Share on other sites
NVADER 54 Report post Posted January 4, 2014 You could just buy a new sensor and install it: http://www.ebay.com/itm/BMW-E38-E39-SEAT-AIR-BAG-MAT-SENSOR-528i-530-540i-M5-730-740il-750il-8367593-/171024394215 A lot of the US based forums seen to suggest that it's an easy DIY for someone who is handy with tools etc. Yeah, although given the genuine BMW part price and the fact most oem suppliers charge around the $300 mark for them, I'd seriously question the quality of a $40 unit, and not being able to rely on it would definitely be unsafe; whereas the bypass leaves no doubt I'm also dark on ebay at the moment. Bought a whole bunch of stuff recently and a good 60% of it was either wrong or faulty Quote Share this post Link to post Share on other sites
KwS 2424 Report post Posted January 4, 2014 Because the wheels are bigger than factory spec and because it's being lowered. Technically that means neither are 'sole' modifications. I've had some hassles with warrants (and roadside police checks) in the past so it's just easier to get them certed and be done with it Im still not seeing a need for a cert... http://vehicleinspection.nzta.govt.nz/virms/in-service-wof/general/tyres,-wheels-and-hubs/tyres-and-wheels http://vehicleinspection.nzta.govt.nz/virms/in-service-wof/general/steering-and-suspension/steering-and-suspension-systems Quote Share this post Link to post Share on other sites
NVADER 54 Report post Posted January 4, 2014 Im still not seeing a need for a cert... http://vehicleinspection.nzta.govt.nz/virms/in-service-wof/general/tyres,-wheels-and-hubs/tyres-and-wheels http://vehicleinspection.nzta.govt.nz/virms/in-service-wof/general/steering-and-suspension/steering-and-suspension-systems It comes down to who you get on the day really as to whether they think that 20x10's are an appropriate wheel size given that the largest factory spec is 18x8.5. It also means there's less likelihood ofhaving to wait on the side of the road while the Police jack my car up. But no, a cert isn't essential. It just saves time in the long run http://vehicleinspection.nzta.govt.nz/virms/in-service-wof/general/tyres,-wheels-and-hubs/tyres-and-wheels#table1011 1 Quote Share this post Link to post Share on other sites
Phil-540i 166 Report post Posted January 4, 2014 It comes down to who you get on the day really as to whether they think that 20x10's are an appropriate wheel size given that the largest factory spec is 18x8.5. It also means there's less likelihood ofhaving to wait on the side of the road while the Police jack my car up. But no, a cert isn't essential. It just saves time in the long run http://vehicleinspection.nzta.govt.nz/virms/in-service-wof/general/tyres,-wheels-and-hubs/tyres-and-wheels#table1011 I think you're on the right track personally, & like you say, it'll save grief & brain damage at wof time, & also if you're having any roadside debates on it. Generally, from my experiances in past, doesn't cost anything more to get 1 or 5 mods certed, & it also helps keep things all above board with insurance company....... On your 20's, so long as rolling diameter is similar to biggest size stock fitment, the only real thing you could get pinged for IMO is the increase in track width....... Its weird in some ways, as technically my ute probably requires cert for its wheels / tyres, yet it gets VTNZ wofs no problem, & is definitely a safer vehicle to drive in ALL circumstances that the rubbish Toyota had on it straight from factory........ My insurance company knows all my vehicles get 'tweaked', so they just accept that & charge accordingly........ 1 Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted January 5, 2014 Really ??? how does this so called weight measuring sensor work ? The Swedish automaker is awaiting approval for a second exemption from federal regulations requiring smart airbags, the same exemption the National Highway Traffic Safety Administration denied last year to Pagani. (Smart airbags require weight sensors in the front passenger seat to detect children, and can deploy the bags at varying speeds depending on the crash situation.) Lotus stopped importing the Elise and Exige to the U.S.—and Tesla, as a result, had to stop building Roadsters—because its exemption ran out. http://blog.caranddriver.com/koenigsegg-to-deliver-first-u-s-agera-in-june-working-on-camless-engine/ More complicated smart airbag systems also include other sensors. Some of these systems can determine the position of the passenger on the seat with ultrasonic sensors, which can allow the system to shut down if the passenger is too close to the dash. Other systems are capable of determining whether there is a car seat present, which will then prevent the airbag from deploying. Other smart airbags are capable of modulating the force that they use to deploy depending on the weight and position of the passenger. http://cartech.about.com/od/Safety/a/Smart-Airbag.htm its been mandatory in the us for years, i presume its on all new bmws. Quote Share this post Link to post Share on other sites
KwS 2424 Report post Posted January 5, 2014 An E38 is hardly a "new BMW" though.... i think its more likely the sensor is just an on/off switch, rather than pressure/weight sensitive 1 Quote Share this post Link to post Share on other sites
Phil-540i 166 Report post Posted January 5, 2014 Ok then, heres a link.............for all the mass debate on it that's wanted, in whats highly likely a more correct spot rather than some-ones project thread....... http://bimmersport.co.nz/topic/47499-airbag-thread-wahoo/ 1 Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted January 6, 2014 yea sorry wasnt really refering to this car in particular as the owner obviously does things correctly. was just talking in general. keep in mind the only way to stop this behaviour in future is to stop it now. in 15 year time if someone does this mod and their "old" 2014 bmw thinks the max weight is in the seat then suddenly the car hits a kid like a 140kg samoan and sh*t gets bad. i would be interested to know how much airbags actually cost the manufacturer at time of instalation. could indicate wether we will see a market for replacement bags in another decade when half of them are getting to old to function. anyway back to 750 goodness. 1 Quote Share this post Link to post Share on other sites
