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  #11  
Old 01-15-2022, 12:47 PM
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Not joking about what to use.

If you use a regular ohmmeter it will be pushing current through the airbag and monitoring the lowering of the voltage as it goes through the system and if that voltage is at or above whatever required level the airbag WILL fire.

Explosive circuits require a specialized ohmmeter known as a (blasters ohmmeter) that is calibrated to NOT set off the cap/squib, etc; but most old school guys run galvanometers due to them being a lower risk (not ZERO risk) of causing an accidental detonation.

An airbag will hit 200mph at full deployment, but an airbag not full mounted or enclosed in the fully installed position will cause even more damage than normal.

Just remember the way and direction each airbag is meant to hit you i.e. upper torso vs shoulder side and what would happen if it caught you say, in the forehead or side of the head...

Say hello to your new C2, C3 injury.

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  #12  
Old 01-15-2022, 04:27 PM
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Thanks for the warning, definitely won't touch it with a regular multimeter.
I've never heard of a galvanometer and it sounded funny and looked like some obsolete scale when I googled it


Please share a link if you know what device would work for airbag purposes, I don't seem to find much on Amazon or on the internet
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  #13  
Old 01-16-2022, 04:33 AM
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Quote:
Originally Posted by Clavurion View Post
Codes for too low resistance are usually caused by the connector locking part which should separate the shorting pins on the airbag side connector.
I checked all connectors, all seems good.
I measured resistance on all connectors, it's around 2.5 ohm on each connector with car off, key out of ignition.
I disconnected driver side door airbag and the error from that airbag changed from resistance too low to resistance too high. I tried connecting passenger side airbag which did not have any errors on driver's side. Error stayed "resistance too high*. I reconnected the original airbag and it read "resistance too low" again.
Now I wish I could measure resistance on both airbags to see what's the difference.
I dont know if driver side airbag is bad or what.
I heard the problem can be airbag module or battery safety terminal.
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  #14  
Old 01-16-2022, 03:33 PM
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I think the side SRS airbags uses a connector that contains a "shorting bar" - the terminals on the airbag are shorted out when the connector is removed (for safety).

If the connector is broken, this shorting bar is not released correctly when the plug connector is re-inserted and the air bag will fault with a "resistance too low" error (due to the shorting bar still being across the terminals).

The connectors are easily broken when removing them - you need to be very careful with these connector...

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  #15  
Old 01-16-2022, 06:08 PM
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Hmmm interesting.
If I measure the resistance in airbag terminals it will be close to 0 since it's now shorted out? When the wire is disconnected from the airbag.

And when I plug the connector into the airbag it will remain shorted since the pin is broken and doesn't separate the terminals of the airbag, which will cause a low resistance message?

I will take some close up pictures tonight.

This would explain the issue of resistance too low.

And I guess when the connector is disconnected from the airbag, it will says resistance too high since there's no contact between the two terminals of the airbag.

Another trip to the scrap yard might be in order to get some connectors and maybe even buy some extra airbags.
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  #16  
Old 01-16-2022, 06:24 PM
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The connector can be "fixed". While I don't recommend doing this, it seems it's possible.

https://www.e46fanatics.com/threads/....680542/page-2

It also seems this might only apply to the older black plastic SRS Airbag connectors - some E53 cars (LCI) have SRS Airbags that use a different yellow connector and may not have this shorting feature.
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  #17  
Old 01-17-2022, 02:38 AM
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You're 100% correct.
The way it works, airbag connectors are shorted out when the connector is disconnected.
Look at the picture and you'll see how there's a a pin that shorts the two terminals.
My right side was fine and I tried removing the plastix top tab of the connector and it broke. I wanted to put it on the driver's side to test.
So what I did instead, I put a bit of electrical tape between the terminals of the airbag and the shorting pin.
Errors are gone!

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  #18  
Old 01-17-2022, 02:58 AM
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The passenger airbag in the dash had a tricky connector as well.
A tab needed to be removed before it could be fully seated. Once I figured it out, that error disappeared.
Until I removed the tab, the connector would not sit all the way. I thought something was broken as well.
Once tab was removed, connector clicked in all the way. The the tab pushed in to secure it.

So right now I only have 4 errors left.




Passenger tensioner and belt buckle errors are probably there because I don't have passenger seat in the car right now.
I'm thinking the seat occupancy is the same problem. Once I install the seat, these should disappear.

Last issue is the battery safety terminal. It was showing short circuit to positive

I disconnected little yellow 2 pin connector in the trunk going to the battery satefy terminal and the error changed to resistance too high

I need to figure out what is shorting to the positive, where and how.
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  #19  
Old 01-17-2022, 03:43 AM
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What's the condition of the smaller of the two large red cables? Does the smaller one show any signs of heating?

The nut that fastens this smaller cable to the BST assembly is well know to become loose, casuing a number of problems, most related to heat damage. Carefully pop open the BST covers and check the nut on the smaller cable is good and tight...

(not an E53 but the assembly is similar)



On an E53 the cover to open is directly below the BST bar code in this image...

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Last edited by wpoll; 03-29-2022 at 08:23 PM.
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  #20  
Old 01-18-2022, 09:59 AM
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The smaller cable nut is actually good.
I connected my audio cable and battery tender there.
It's the large cable that I think could be the issue.
I see some electrical tape there.
I'm thinking the Pyro fuse must've blown when the previous owner had it.
Maybe then he pushed the cable forward and added this tape to hold it. And maybe this led to the error with SRS

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