1999 SDM/BCM/Airbag linked to VIN like 2000+???

[ostste]

I have a 1999 Buick Century Ltd that recently had the airbag light come on, I believe as a result of some light water that leaked to the passenger side through a weak seal (near cabin air filter; has since been resolved). I believe the water may have damaged the SDM under the seat, although I have not taken it anywhere that has a Tech2 to look at the codes.


I know that for years 2000+ the SDM and BCM are linked to the VIN, but have struggled to find if this holds true to the 1999 models. If not (and if the codes come back indicating the SDM), can I head to a pull-your-own-part yard and grab one?

All of the things I can find regarding the link between BCM/SDM/VIN are in 2000+ vehicles.


Thank you!

 

[ryenie]

I don't see where it says you have to flash the new module with the VIN for a 99, just replace then enable SIR system and you should be good to go. The only difference I see between 99 and 00+ is that starting in 00 they introduced the side airbags, and they require a different module to operate.

 

[ostste]

The only difference I see between 99 and 00+ is that starting in 00 they introduced the side airbags, and they require a different module to operate.

I'm fairly positive that in the 00+ models you can't just pull the SDM from another car, and that the SDM/BCM have to match VINs (furthermore, as I understand you can't flash it with your new VIN, it's a one-time thing, thus requiring a new module to be flashed).

My source for this is: http://www.justanswer.com/buick/7b5...centurypassenger-airbag-driver.html#re.v/491/

In particular he states:

The vin numbers in the SDM, BCM and PCM must match or a b1001(option configuration error) will be set and the deployment loops will be disabled. Vin numbers can only be programmed into a BCM or SDM one time. Therefore a used on will have the vin from the previous vehicle locked into it and it cannot be programmed with any other vin. Again, with the vin mismatch the system will be disabled so replacing it with a used one will have no affect on repairing the system.

The 99 has a different setup procedure. The BCM is different in the 99. BCM is body control module, SDM is sensing and diagnostic module (the air bag module) and PCM is powertrain control module which is the engine computer. In a 99, the BCM would have to be setup with the SDM part number using a dealer tech II scan tool. With the 2003, the setup procedure must also be done but in addition, the vin is burned into the SDM which then locks it to that vehicle.

I guess my REAL question is how to interpret that last paragraph. As far as I understand it seems to say that if I have access to a used SDM and a Tech2 tool I should be good to go?

Thanks again!

 

[ryenie]

The SDM installation for a 99 is pretty straight forward, after looking through alldata for a 99 you simply disable, install, re-enable and good to go. Replacing the BCM requires a capable scanner to program, but not necessary to program if replacing the SDM. Yes a 2002 and up requires the BCM to be programmed with the new part number, but not the 99-01.

 

[ostste]

That is great news! Hopefully I'll be able to find the part I'm looking for.

A few follow-up questions (you've been terribly helpful and I hope this isn't a bother):
1. When you reference disabling, is that something that can be done without a scanner? This all-data seems like a helpful tool to have haha.
2. I'm still working to figure out how to get to the SDM, and I actually have a 2000 Buick Century that was recently in an accident and is sitting at the tow place until we sign the title over. I wonder if it is easy enough, if I would be able to grab it from that vehicle while picking up my belongings from it? Or would it be fairly labor-intensive?

Thanks so much for all of your help!

 

[ryenie]

It is a useful tool, when I was in tech class it was required to have it on the over head monitor to work on any of the cars in the garage, even on bring your own car friday. It's a subscription based computer program, as far as the disabling, re-enabling yes both are done without a scanner on your car, once you get to newer year models or maybe even just different makes, there is a tool you have to plug into the air bag wires to disable it, but for your year and make its not necessary. As far as using the module from a wrecked car, I'm nor sure if that will work. My understanding of the system, and I need to stress this, I don't know if it is universal, year specific, make specific, or pertinent, but the SDM acts like an airplanes black box, if it detects a collision it stores all the data from all the modules, I don't know if this data can be erased, if not the airbag light will stay on. It may also have codes stored in it, don't know if they can be erased as well. If it can it would more than likely require a tech II scanner. The SDM from a wrecked car might be answered better by a collision expert.

 

[ostste]

Ah, I should have specified that the car was in a collision, but the airbags have never deployed (the collision busted up the front end/radiator/etc that we decided to not spend the money to fix it and instead upgrade one of our vehicles.

 

[ryenie]

I don't know if it has to set the airbags off to have detected a collision. The airbags are only supposed to be deployed in certain types of collisions, but it still may recognize there was a collision, and recorded the data. I would say swap it with the old one and if the airbag light stays on to have it scanned. If not there shouldn't be any issues with the air bag system. I would also stay clear of the airbags until you verify the system is operating correctly. After you enable the air bag system the light should flash so many times and then go off. There are reportedly many ways the system can accidentally go off and cause serious injury so be careful around it until you get the light to go off.