BMW E90 Airbag light on error 93C2 Fault finding and repair with Autel MaxiSys

We're gonna be working on the car BMW E90 on the airbag systems with Autel Maxisys , this is a warning and advice, if you’re not sure of what you are doing, please don’t do it, don’t touch airbags can be dangerous. I take no responsibility for anything that you do based on my information on what I’m doing here, if you do it, do it at your own responsibility, so yeah that’s just a quick warning and now let’s go to crack on.

Hi everybody, all my followers be welcome to another video, so I had to skip but I don’t know which we’re going to go first by the 207, it’s just over there, you only see the front of it, the part for it is over there, unfortunately the owner is going to take away because I don’t have wheel max or wheel bolt locking key for it, so I can’t take the wheels out I was looking to see if I could do the job without taking the wheels, probably I could would be an absolute nightmare, so I spoke with the owner and he’s going to take the car elsewhere to remove the wheel bolts or the security ones.

Yes I know there is some sort of a universal keys I can buy that kind of feeds different types of a security bolts I don’t have nothing like that, it’s not my problem, I’m he’s going to try to sort that out in the meantime he’s going to pick up the car very shortly, in the meantime, we’re gonna work on this 2008 BMW 320i, I believe this is the 90 or some other and the problem with this is let me show you.

I mean actually start the car. That’s my problem, as you can see, we have a airbag light issue. As you can imagine the first thing we’re gonna do is scan the car.

Okay, go to “menu”, it’s gonna go to my airbag unit, that’s going to be most likely “body”.

Let’s kind of see why we have.

Okay, so a quite simple I guess, so under voltage that’s below battery a seat marked of passenger seat occupancy detector faulty.

Let me speak with the owner because well we’re gonna do a couple checks just before, just in case he’s a wiring problem, or if he’s a sensor problem.

Most of you are already saying out loud just feed a emulator for the seat I don’t know yet what I’m gonna do let’s go to find out where the owner see what he wants to do.

But let’s go do a couple checks first and then we’ll go from there.

Okay, that was quick to take the wheels, the bolts off, anyway spoke with the owner of this car and I explained to him what the problem is with the passenger seat, although we can say we are boarding the system, we are really not because the airbags will still function so basically he wants to go the bypass route and so the occupancy sensor on there is mainly because if someone is on the passenger seat if the car detects that someone is in there, he obviously shines the line for the seatbelt, and if you have an accident that airbag will deploy if someone is on the seat if the car doesn’t detect no one on the seat and you have an accident, the airbags will not deploy, if we go the bypass route, what happens is if they ever have an accident, even if someone is not on that seat all the airbags will deploy because we’re going to tell the car that there is someone on that seat all the time.

As far as I’m aware but I’m not gonna go to bypass route anyway, I’ve never installed one of those bypass, we’re going to try something slightly different here, which will do the same thing really.

So just stay tuned and we’re gonna change tools and I’ll show you what we are going to do.

OK, and after a couple of hours a we’ve been doing other stuff, but look at all absent so we’re going to clear the codes.

Because the light will not go off until they clear the code,

So read the codes again, no fault detected my airbag light is off.

I’m going to go back it’s going to go into “Live data”.

So as you can see in there a front passenger seat occupancy detection: passenger seat sensor and airbag active which means obviously the airbag is gonna work regardless of someone on the seat or not, but the airbags will work that’s why the owner wants to do, so that’s what we did.

Now I haven’t completed yet we’re going to have to still put everything back on, but nevertheless I’ll show you what I’ve done.

And before some of you are going to start to shout that this could be done through coding possibly I couldn’t do it, um coding would fail every single time, the car has been flashed in 2011, my Titan files for the MC’s expert a version 40 which is a quite old version to be honest, I’m now loading a version 52 or 60 some other so hopefully it will give me a different a different options to code on the module, but the module would just not take any coding, nevertheless the OC3 I think it was not active, it was another couple things for the say that were not active, so I do have a feeling that someone already tried to deactivate this but obviously didn’t work even because when I go underneath here, the sensor was already plugged, but the plague was not on this place which is this little thing here, let me show you the sense of the plague, cause here on this little square goes here on this little square, and this was just hanging off and the cable was slightly ripped, pull down so someone has been here before me and I believe someone coded these off and it didn’t work, so what I’ve decided to do was to know I haven’t done any more later, so as you can see, this is the original sensor, and here these four traces is where the actually map that goes down under the seat is connected, so I took these off as you’ve seen in there so I had to take all these off.

Pull the base out to expose this and carry out and then I’ve done this little circuitry here which simulates the seat with someone there, basically he simulates the map with someone in there so now rocket science car is no more than four resistors as you can see,

these are they are connected, so they are like a square, so we have 21k ohms, one year, then you jump these two with a 1k ohms actually these ones, sorry I’m lying now, this is 1k ohms, this is supposed to be 2k ohms, I didn’t have a2KM, so I put 2.7 ohms so these two here on the sides are 2.7 but he’s doing the work, so it doesn’t really bother me, so one came here then you jump these two with 2k ohms and then from here you take one wire to the first bin or to the first trace, then from the other one you take another one to the second trace and so forth, and this is always connected, so now I know is working, we are going to tie this up a little bit, so I’m not going to put this under the seat again, I’m going to somehow put these underneath here somehow.

But yeah that’s what we’re gonna arrange these 2 look slightly better and put everything back on and that’s about it really so, I don’t know yet how I’m going to do this, I’m gonna have to find a way I guess I don’t know yet how I will find a way.

Let me see how we’re gonna do this.

This is very important check that you have power in grounds here, so the way the sensor works, you just have a power and a ground and a Lin bus, so the way this communicates with the airbag module is with a Lin bus, so make sure as the first thing you want to do is check powers and grounds because if for any reason, there’s a broken wire and you don’t have power in grounds, obviously this is not going he’s not going to work so the first thing I’ve done, let’s make sure I had power in grounds is these three pins here okay, so the first pin I believe is ground, the second pin I believe is voltage and the last pin is Lin bus communication, okay, so make sure you have that, and then obviously only then move forward if you don’t have power and ground make sure you get the power and ground sorted first before you go any forward.

Okay, and I decided to pull these out again so this is the final result so I’ve done this with a melted plastic glue, I’ve just did this setup, it doesn’t look very good, but I decided that I would be putting it back where it belongs, which is right here, I’ll just pull this leatherback and I’m gonna put it right here, so that’s where I’ve cut the sensor as you can see the matte, that’s the mat that comes under the seat I used to be right there, so we’re going to put these in the same place, hold on a second there is exactly where he belongs so we’re going to put everything back on now put the seat in place, connect everything and do a final test.

Okay, everything’s done and I just have the Autel MaxiSys is there to show you something, so for you guys that know a little bit about this, you probably in the background saying haha, that’s not gonna work just yet well and it didn’t, because from the moment you tell the car that someone is in the seat all the time, the seatbelt warning does not goes off until you buckle the seat belt, so that’s another issue and so that we have to sort now forget about to try to short the contacts for the buckle or whatever it doesn’t work like that, even I don’t know exactly how it works.

I think there’s a couple ways I could do this, but the best way to do it I could probably try to open this and switch these inside the buckle here, open it and just trigger the inside all the time at the play, forget about it, the issue sends a pulse voltage to the buckle, I’m not sure how he works I didn’t dig into it and the reason why I didn’t is because literally I’ve just go to the car, the air bag module I called to the module as if this contact does not exist for that, I’ve used Autel MaxiSys, but you can use MaxiSys expert if you want and all you need to do is hat JKBF to the VO, in this case is a keyword, or HO-Wort, what whatever is I’m gonna show you.

So, HO-Wort, that one I have OI12 is for seatbelt warning as you might have seen as you might have seen in there the good thing with Autel MaxiSys gives you a list of all the options so, the belt contact which is the first one we disable that and we disabled the belt warning I didn’t really have to do that one, because the contact is disabled, but I just did both nice and quick, it’s a little bit late I’ve been busy with other stuff and you do that on the MaxiSys by coming down here. Go there and then press “Edit”, you can do this with the NCS expert, if you want.

So once that is done obviously the mat still needs to be there, so that’s how we did it, for the seatbelt guys, if you don’t have the Autel MaxiSys, you can actually buy one, as well for the mat sensor as well for the seat occupancy sensor, you can buy an emulator for both for the seatbelt warning and for the Matt obviously I decided to do it this way, so we triggered the sensor at the at the math module and we coded the seatbelt contact off and I’m going to start the car just to show you. Yeah, so the reason why the bonnet is open because I had the factory charging. Okay, so obviously it’s on because my seatbelt I didn’t not disabled, the driver seat belt, so I’m going to put the belt I’m going to see it goes off.

That’s it problem solved.