Passenger Front Airbag Deployed.

Hello!

In my 1999 Passat TDI, the side airbag was deployed due to an accident.
Okay, so here's my question.
What needs to be replaced so that the airbag will deploy again?
Is it sufficient to replace the side airbag and the crash sensor, or does the control unit also need to be replaced? I read the error memory using VAG software, and it shows that crash data has been stored.


Thank you.

It always depends on which generation of airbag system is installed (the part number of the control unit would be helpful now). Also, please post the specific error codes you are seeing...

Basically, you will need to replace the crash sensor (NOTE: Make sure to order the correct one!!!) and the side airbag unit. Some control units allow the error codes to be cleared up to 3 times in the event of a side impact.

Hello Sebastian,

Can you provide something specific for a Volkswagen Golf 3 with engine control unit (ECU) 1J0 909 608 A?

I have the STG (Steuergerät) in my Golf, but I've already deactivated the side airbags using resistors (because of the sports seats).

The buyer of my old seats with airbags has the same control unit (ECU) in his G3. In his case, both (!) side airbags have been triggered. He now has the seats with the airbag wiring harnesses. He probably still needs to replace the side crash sensors as well.

Since I don't need it anymore, I'm considering replacing it with a wire bridge (or open end) and selling it as well.

Can he reset the airbag control unit after that, or does he have to replace it?

Best regards,
Guste.

PS: According to the buyer, both airbags deployed simultaneously after he hit a curb rather abruptly. Is this normal?

guste100 wrote:

Can he reset the airbag control unit after that, or does he have to replace it?

He most likely has to trade.

guste100 wrote:

P.S.: According to the buyer's information, both front airbags were deployed simultaneously after he hit a curb rather abruptly. Is that normal?

Normally, definitely not, but at least something like that could happen.

@Sebastian:
Thank you for your reply!

@Everyone:
Does anyone know the internal electrical structure of the side crash sensors?

So far, all my attempts to remove the part without the ECU reporting an error have failed. I have already experimented with various resistors, as well as connecting two diodes in series, and I have also extensively tested a diode-resistor combination, but without success.

Regarding the measurements: I am measuring approximately 14.5 kOhms on the intact sensor, as well as a diode characteristic with a breakdown voltage of 1.3V.

Any ideas?

Thank you and best regards.
Guste.

Hi, I've made a little more progress.

I received the defective sensors from the customer. They are sensors from Temic (MRSA Sidebag). Inside, there are two ICs among other components, but these ICs have custom markings.

A 28-pin Motorola IC with the following inscription:
MRSA VW V3.0W
0F82B
CTCTAK9642

The second one is an SO8, the markings of which I cannot identify under the layer of paint. A picture of the sensors is attached.

Is anyone in the forum who can tell me more about the sensors? Feel free to contact me via PM or email (Dieselschrauber's username at gmx.de).

As I said, all I want to do is disconnect the sensors without getting an error message. The side airbags have already been removed, so the sensors are unnecessary anyway.

Thank you and best regards.
Guste.

Hi,

I'd say something digital is coming out of it. Connect an oscilloscope/logic analyzer.

Best regards, Rainer.

Rainer K. wrote:

I would say that something digital is coming out of it.

Correct, a data transfer takes place, during which, for example, the sensor's ID/version is transmitted to the control unit.

Sebastian@OpenOBD wrote:

Correct, a data transfer takes place, during which, for example, the sensor's ID/version is transmitted to the control unit.

Oh, so my fears about the 1-wire bus, including the power supply, have been confirmed (the sensor only has GND plus one additional wire that has to carry the power supply, data, and crash signal, so it's probably a modified Dallas 1-wire).

I didn't think the crash sensor would operate using a digital signal. Surely, it should transmit the impact information analogously, or the bus must have a very high speed to keep the delay until the trigger reaches a reasonable level.

Thanks, Sebastian, for the information. Now I know that I can't emulate it so simply.

It would be interesting to see if I could trick the triggered sensor into thinking it never triggered. I could then install the formerly triggered sensors in my car (which doesn't have side airbags anyway) and give the ones that haven't been triggered to the seat buyer. However, that would probably require quite detailed information about the sensor.

Best regards,
Guste.

I may need to qualify that statement somewhat, as newer airbag systems do that, but I can't say whether that applies to your older "VW2/3" model.