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Hello All, new to this forum. here is my situation.

I own a 2005 Mazda 6, which I have had for a few years now, 2.3L, 5 Speed manual, has been a very reliable car, although is now on around 320 000km, so certainly has had some use.

I have been given a second car, it is also a 2005 Mazda 6, 2.3L auto. around 130 000km I believe. This is the story I have been told, with it

The owner was driving it daily, when it went flat one day, they attempted to start it one day, and it wouldn't start, so they had a mechanic look at it, and put a new battery in it. The new battery was installed, and when the mechanic attempted to start the car, every airbag instantly deployed. The mechanic somehow determined this to be a problem with the alternator, his reasoning was "The alternator overcharged the battery and caused this" the mechanic than gave the car back to his customer as is, and I have now come in possession of it.

I have my own doubts to this story, but that is what I have been told.

here is my "goal"

as my car, is getting on a bit, with age but also has a few dints in it, and the second has is in otherwise much better condition, my plan would be to
fix the issue, with whatever caused the airbags to deploy
move my airbags to the second car
move my manual gearbox, and associated components, (ECU, wiring loom, pedalbox, BCM? does anyone know what else would be needed, or is there a guide on what is needed for the conversion)

my question now, where should I start with testing, to see what could be causing this. I ideally don't want to be blowing up airbags left and right needlessly while testing. is there some way I could test, if the car is sending a "deploy" signal to an airbag, without plugging in an airbag and risking it.

Is there possibly any truth to what the mechanic was saying about the alternator? does anyone know a way I could test this.

would it be possible that the issue could be related to the ecu being damaged, possibly when someone has failed when trying to jumpstart it, and the issue might disappear, when I swap over my new ecu

Any help is much appreciated.
 

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Hello, I was going to comment on why all that work would be done swapping active restraints and drivetrain and all the wiring and then I saw you were Australian. You guys down there are on another level when it comes to cars and repairs/modifications. ?

The SRS computer will need to be reset (following deployment) or a new one matching the ECM/BCM combo of the vehicle it is going into.
I believe the training manual will have the voltage parameters you need for the airbag computer. I assume both cars have the same bag configuration? six bags into six bags or 4 into 4?

If you are swapping over your ECU BCM and SRS modules I would bet it would be okay. You will likely need to transfer the front seatbelt retractors as well but I am not entirely sure if they fire on both sides if there is no passenger sitting in the seat. I would guess you would have to, because the passenger bag deployed even though no one was seated there (assumed) I would imagine the side impact sensors can be reused if they are the same model.

I would just bench test the alternator. I believe the training manual again gives you oscilloscope data for that.

EDIT: I was told by the guy that reset my SRS computer that it was important the the battery was disconnected before plugging or unplugging any airbag related system. He also told me that when I reconnect the battery to make sure the ignition was off or it could cause SRS issues. I wonder if the battery was installed with the ignition on and this somehow caused a spoke as the capacitors in the vehicle electronics charged and stabilized? IDK...
 

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wow. that’s something. Unfortunately, when it comes to airbags.. my knowledge is limited.

I do know for a fact that it is ALWAYS wise to disconnect the battery when ever dealing with airbag systems.

Sensors, airbags, modules, and seat belts (some- all?, modern cars will permanently lock the seat belt restrain system when multiple air bags have to deploy in a severe crash), are all expensive and not something you want to go to the aftermarket for. Some of it can be reset by OEM-level scan tool. Others will have to be replaced.


Keep us apprise on what’s done and so forth. I am sure it’ll come in handy for someone else



(╭☞ ಠ ͜つ ಠ )╭☞ r=1+sinθ
 

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Check to see if it falls under the Takata recall.
The recall has nothing to do with random firings of the airbag. It relates to faulty airbags and that’s it. And the faulty airbags will still fire but with a higher likely hood of metal fragments being sent that way. I refused plenty of recall claims as the car was in a previous accident(and not repaired) , had wiring issues, etc etc.

Chris
 
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