Have you ever measured resistance on an airbag with DVOM
Please Log in or Create an account to join the conversation.
I did put a scope on a pretensioner circuit before! Got a lot of flak from others for that, too. :silly: Oh well.
Speaking of the ohm meter, has anyone measured how much current one generates? :huh: I feel like Paul may have at one point...
Please Log in or Create an account to join the conversation.
- ScannerDanner
- Offline
- Administrator
- Religion says do, Jesus says done!
- Posts: 938
- Thank you received: 486
On a separate note. I've recently learned the hard way to NEVER rotate an airbag module with the key on. Smh
The rollover sensors are in the module and it blew the side curtain bags. Yes, I have it on video too
Don't be a parts changer!
Please Log in or Create an account to join the conversation.
I'd love to see the video Paul
Please Log in or Create an account to join the conversation.
Tyler wrote: Never. Always wanted to.
I did put a scope on a pretensioner circuit before! Got a lot of flak from others for that, too. :silly: Oh well.
Speaking of the ohm meter, has anyone measured how much current one generates? :huh: I feel like Paul may have at one point...
I'd also like to know how much current the ohm meter generates. I think Paul has mentioned in one of his videos it's in the milliamp range.
Please Log in or Create an account to join the conversation.
- Posts: 4431
- Thank you received: 962
I didn't know about the module thing though! I'll be cautious when it comes to those from now on.
"Ground cannot be checked with a 10mm socket"
Please Log in or Create an account to join the conversation.
- Andy.MacFadyen
- Offline
- Moderator
- Posts: 3353
- Thank you received: 1031
The plug connector on an airbag has a shorting bar so if you try and measure the resistance unless the the shorting bar is lifted clear or put out of action the airbag or pre-tensioner squib with read a dead short. Substituting 2 ohm resistor is still probably the easiest test.
My experience sugests where there hasn't been a crash impact 95% of air bag faults are due to bad contacts in connectors, 4% are down to water ingress into the impact sensors.
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
Please Log in or Create an account to join the conversation.
- Andy.MacFadyen
- Offline
- Moderator
- Posts: 3353
- Thank you received: 1031
The other question is how much curent is needed to set off an airbag squib
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
Please Log in or Create an account to join the conversation.
Then, what is the cost of the failure you might cause vs. the value of the time saved? There was one piece of equipment I worked on where you needed to clean an optical sensor when doing a service. Getting to the sensor by the book took 20-30 minutes. But, you could bend a metal flap slightly, pull it out and have access to the sensor; which took about 20-30 seconds. If you slipped you could damage a $200 part though. Given the time saved doing several of these jobs a week it was worth the risk but if it was a potentially very expensive part (like airbags) it would not have been worth it (IMHO).
Please Log in or Create an account to join the conversation.
- Andy.MacFadyen
- Offline
- Moderator
- Posts: 3353
- Thank you received: 1031
From what I think reliable sources the amperage used for firing off a single air bag pyrotechnic is 1 to 3 amps ---- which implies they should fire reliably at as low as 2 volts.
Measuring my varied collection of meters testing the open circuit voltage accross the test leads on the ohms scales none showed more than 300mv open circuit voltage.
Putting 3 ohm load on and the voltage accross the load dropped below anything I could measure with any of my meters and current was measured in all cases at less than 0.3ma
So know your DMM and make your own judgement at your own risk --- I would not advise using a Power probe or old style analogue meter (aka an "AVO" meter) Having said all that airbag pyrotechics are dangerous and substituting a 2 ohm ressistor is still the weapon of choice.
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
Please Log in or Create an account to join the conversation.
Totally agree here. I do NOT encourage anyone to measure resistance on an airbag. Even if the chance is pretty small for the airbag to deploy and there's a shorting bar to bypass don't risk it. A loose airbag unit that explodes is lethal.
We used to set off airbags at the Toyota dealership after replacing them because of some TSB. Can't remember what the issue was. But man the first time I did that I'll never forget. I squeezed it very tight in the vice, took some wires and a battery. The thing wouldn't even go off just by putting battery voltage to it. So I started pulling some sparks at the battery and that was the loudest bang I've ever heard. Boss ran into the shop. Poor guy thought his garage was gone. I'm laughing now but I wasn't at the time :lol: Should've taken it outside and blow it on the roof.
Please Log in or Create an account to join the conversation.
- Posts: 4431
- Thank you received: 962
I know it was at least 30 feet because it landed on top of the car stripping tent and bent one of the supports...
"Ground cannot be checked with a 10mm socket"
Please Log in or Create an account to join the conversation.
- Andy.MacFadyen
- Offline
- Moderator
- Posts: 3353
- Thank you received: 1031
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
Please Log in or Create an account to join the conversation.
- Posts: 4431
- Thank you received: 962
"Ground cannot be checked with a 10mm socket"
Please Log in or Create an account to join the conversation.
Please Log in or Create an account to join the conversation.
- juergen.scholl
- Offline
- Platinum Member
- Active partschanger
- Posts: 1201
- Thank you received: 447
So the resistance box is suitable for checking out the air bag circuit.
An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing.
Please Log in or Create an account to join the conversation.
Please Log in or Create an account to join the conversation.
I see know need to, to be honest. Substitute the bag in question with a resistor of equal value and if your code goes away, the wiring and computer are fine.
On a separate note. I've recently learned the hard way to NEVER rotate an airbag module with the key on. Smh
The rollover sensors are in the module and it blew the side curtain bags. Yes, I have it on video too
WOW !!
Never knew or thought that could happen, for sure never mentioned in the BOSCH (UK) Airbag Training course. In their (Bosch) defence they do teach you to handle Airbags with Ign OFF & Battery Disconnected and allow time for Caps to discharge.
Im so glad I read this - Lesson Learnt, Disaster Averted !!
Please Log in or Create an account to join the conversation.