Technical Airbag light on after alternator failure

[Rby21]

Hello guys, good morning! I am having trouble with my 2007 1.2 48kw grande punto active's airbag system. After an alternator failure, the airbag light came on, B0100 - control module faulty. After a few days, I parked the car and I forgot windows down, so I turned the ignition on and off rapidly just to get power to the windows. When I came back, the airbag light was gone. It worked for about a week, until I accidentally stalled the engine. (drove an automatic prior to getting into my car ) And now it is back on.
Checked with a Delphi again, and it has the same code - B0100. Since I know this car has a lot of electrical gremlins, I wanted to check here first and see if there are any other fixes, before searching for an ACM. Thank you!

 

[GrandePunto PL]

What's the point of starting new thread? Since you know about "electrical gremlins", sort/rule them out first.
https://www.fiatforum.com/threads/the-electrical-gremlin-thread.318839/ Then we can talk.
Most problems are caused by power quality issues: battery, alternator, main "ground/earth" and main fuse box (corrosion).

 

[Rby21]

Hi, I'm coming back to this. Since then, I've cleaned the ground cables in the engine bay, didn't touch the gearbox strap because I didn't want to touch the clutch cylinder. Sadly the airbag light is still on. Only things I have to check are the interior grounds, and, of course, the main strap. If all the electrical stuff will not solve the problem, I think the last option is to swap the unit. If I swap the unit, do I have to do a Proxi Alignment?

 

[Redeagle]

Does it have a code?

 

[Rby21]

Does it have a code?

An error code, you mean? or?

 

[Redeagle]

An error code, you mean? or?

Dtc?
Try taking battery earth off if you have spanner or jump lead contact negative ((only wire! )) and positive wire for 5 minutes this will completely drain residual power in system and may clear the issue. Reconnect negative and try again. Some code need diagnostic tool with airbag reset function to clear code. Hope that helps.

 

[Rby21]

Dtc?
Try taking battery earth off if you have spanner or jump lead contact negative ((only wire! )) and positive wire for 5 minutes this will completely drain residual power in system and may clear the issue. Reconnect negative and try again. Some code need diagnostic tool with airbag reset function to clear code. Hope that helps.

I do have a dtc, its b0100 - control unit faulty. Even though I had this code, the car had moments when the warning light would go off for 2-3 days, and then it would come back on, with the same error. Last time it came back on and it didn't go off since then. I will try to jump the wires, maybe it will help. Thanks a lot!!!

 

[Zardo]

If it clears itself and later comes back again, looks like an intermittent fault.

Maybe parasitic voltage on the 12 V line (noise), a connector problem, humidity, a faulty capacitor somewhere (maybe even in the airbag unit itself), bad earth strap and so on.

I once had to change my airbag module in a 1995 Fiat Bravo because it was placed right under the heat exchanger which had gotten leaky. Coolant fluid dropped on the airbag module which was just a metal case, without any protection against humidity. The coolant destroyed the unit which had to be replaced (and the leaky heating was also replaced). Don't know about the 2014 GP, hopefully it's better protected now. Also, modern cars have climatisation.

 

[Rby21]

If it clears itself and later comes back again, looks like an intermittent fault.

Maybe parasitic voltage on the 12 V line (noise), a connector problem, humidity, a faulty capacitor somewhere (maybe even in the airbag unit itself), bad earth strap and so on.

I once had to change my airbag module in a 1995 Fiat Bravo because it was placed right under the heat exchanger which had gotten leaky. Coolant fluid dropped on the airbag module which was just a metal case, without any protection against humidity. The coolant destroyed the unit which had to be replaced (and the leaky heating was also replaced). Don't know about the 2014 GP, hopefully it's better protected now. Also, modern cars have climatisation.

Hi, just came back from the car, tried to jump the leads, and the error is still there. I got the earths sorted out, however it's one I didn't touch : the gearbox strap. I was afraid to, because I didn't want to do something wrong and have to bleed the clutch. I will try to sort that one too, but I am losing hope that it would have some effect

 

[the green vanper]

The airbag module is sensitive to voltage fluctuations. It might be it was damaged when the alternator failed.

There are several threads here on the airbag modules failing due to battery disconnection, pretensionners change or even swivelling seats in a motorhome.

The error says module failed.

The engine - body earth strap would be more likely cause any problems with engine starting not the airbag module, but it's worth checking it, too.

I'm replacing the earth straps with good quality copper welding wire. That's a photo from a previous thread when I showed how does it look. It's a non-FIAT car though.