Zündung an oder aus bei Masseanschluß an Batterie | Posts 16+

Hmm...

Regarding airbags, there are differing opinions. It's common practice at VAG (Volkswagen Group) to turn on the ignition before connecting the battery during airbag repairs or modifications. Despite the potential risks involved, it somehow makes sense. And if the electronics aren't adequately protected against voltage spikes, there was a flaw in the design from the beginning – see the E-Class.

Okay, but if the entire electrical system is switched on at once, and then all the control units start working completely uncoordinatedly...
It usually produces beautiful error messages, especially when you're messing around with the battery terminals...

And it repeatedly shows that reality is often more extreme than any simulation or safety mechanisms can anticipate.

CU Gremlin.

I just wanted to briefly share the ending:

This week I had the TÜV (German technical inspection). I drove there, the inspector got in, he saw the airbag warning light on, and said that without it, I wouldn't get the inspection sticker. I explained the situation to him, and he said, 'Okay, we'll do the TÜV anyway. You clear the error memory, and when you come back and the light is off, you'll get the sticker.'
I went to a VW service center, they cleared the error codes (the error message was: 'Airbag resistance too high'), and everything was okay!

P.S. Just so you know, because I have a semiconductor replacement module, I also received an error message indicating that the control unit was locked.

This thread is a bit old, but it's a perfect fit.
This weekend, I installed my GRA (presumably a device related to the car's electronics) and, of course, I had to remove the airbag for this. As VW states that the ignition should be switched on when connecting the battery, I simply tried it. So, I turned the ignition on and connected the battery. I used a screwdriver to carefully and precisely reattach the battery terminal with a bit of force.
Result:
All control units remained undamaged.
The airbag remained deployed.
Airbag light is off.
However, two errors were saved (previously, the memory was empty).
Firstly, it's blocked in the MSG (Message Service).
and in the KSG building - no connection to the SG building, back door on the left.
I cleared both errors and then read the system again after the test drive. There are no new errors.

Just sharing my experience.

Hi everyone,

I don't want to be holier than the Pope, but when it comes to airbags, that's where the fun stops.

Modern airbags contain explosives and have a serial number (not only for that reason). The entire lifecycle of an airbag, from manufacturing to proper disposal, is officially monitored. If an accident occurs involving a removed airbag, or if an accident happens in a workshop during the installation or removal of an airbag, the first thing that is checked is whether the airbag should have been present at the accident site, how it got there, and where it came from.
Before a trained mechanic is allowed to remove or install an airbag, they must pass a corresponding examination! This training includes, among other things, how to properly store an airbag. It's even difficult to buy an airbag, even from a supplier around the corner.

Regarding airbag errors, everything has already been said: errors remain stored in the system until they are cleared; this is the regulation!

The ignition remains off when connecting the battery. Someone who is familiar with airbags knows what they are doing and turns the ignition on after installing the airbag and connecting the battery. If you are unsure about any of this, it is best to avoid working with airbags.

For electronic control units, voltage spikes and fluctuating voltage levels when connecting the battery can be extremely stressful! That's why the ignition should remain off. The battery terminal should be quickly and firmly connected to the battery terminal post in one smooth motion.
If someone wants to damage their electronics, they could turn on the ignition and, while connecting the battery, repeatedly trigger the sparking.

Regards,
Sure, here is the translation of the text from German to English:

"Micha"

@Mephisto
I don't believe anyone has questioned the fact that handling an airbag poses a risk.
The instruction manual for the aftermarket installation of a GRA (Gas Return Actuator) from VW even mentions that the ignition should be turned on when connecting it. If those are the same manuals used to train people on how to handle airbags, well...
On the other hand, I hope I don't have to make that decision again – whether to turn the ignition on or off – when connecting the battery. I certainly didn't enjoy it.
Best regards,

Hello,

From my own experience, I can only add: never turn on the ignition if anything is disconnected or tampered with regarding the airbag system. Even if the airbag warning light is off, turning on the ignition will cause the light to illuminate permanently (as soon as it's reinstalled) due to a sporadic error.

It's a bit off-topic, but here's a pretty good explanation of what's going on with the mystery airbag control unit/sensor (this is not an advertisement or recommendation, I'm not familiar with the company).

Regards,
0588.778

Edit: Link removed by Jan6K for [reason].
a) Nonsensical information on the landing page.
b) Avoiding legal trouble for the target website due to criticism.

Hi,

If I only read the texts...

...is a magnet. ...because there is also magnetism inside, an induction is created.

I've never seen anyone describe induction without mentioning the word "coil." Furthermore, your claim that nothing breaks in an accident is not only false, but also dangerous. It's true that in 90+% of accidents, the airbag control unit and sensors won't be damaged, but no one can know that for sure without extensive investigation.

They probably describe the function adequately, but everything else is simply appalling.

Best regards,

Jan.

Hello,

Well, it seems this young man really doesn't have a good understanding of how an airbag control unit works. The component he so neatly disassembled (with the magnet) is only part of the acceleration sensor, specifically the so-called safety switch. The safety switch is actually only used to verify the acceleration; in other words, the acceleration sensors and the safety switch must both detect a deceleration in order to trigger the airbag.

The instruction from VW to leave the ignition on when connecting the battery is equally alarming. They should be glad that nothing worse hasn't happened yet.

By the way, most airbag malfunctions occur during ignition.