Air bag light problem

[Gozoman]

Bit of technical advice required. I fitted a new battery to the car today. I always use a back-up power supply connected to the OBD2 port in order to retain all system settings. When I had finished and started the car all was normal apart from the following message; Restraint Sys. Malfunction. Consult workshop, and the airbag light is on. Is this something that I can reset myself, I have an iCarsoft MB II diagnostic tool? My concern is that I might be able to reset it but end up with no airbags. My other concern obviously is that I take it into Mercedes and get stung for a big bill with Christmas coming up. That happened before when I got hit with a £600+ bill for something I could have did myself for under £40! Now obviously the airbags are important and I don’t want to take any chances so if it needs to be a workshop visit so be it.

I’m wondering if it could have anything to do with this little terminal on the positive battery clamp. I’m referring to the blue, black yellow thing with the two wires going to it on the right hand side. This isn’t mine it’s a photo off the net but when I took my positive clamp off this basically came apart. It was broken and only still in place because the clamp was holding it in place. I found that it went together again easy enough and I repaired it with epoxy resin and a couple of cable ties to hold everything in place until it hardens. Anyone know what this actually is and could it be related to my problem?

 

[bob6600]

I would try clearing the fault, if it clears, your airbags will be fully functional. If it doesn't, the code should give a clue as to what is the fault. Sounds like a seat belt tensioner fault but I can only guess.

 

[Gozoman]

I would try clearing the fault, if it clears, your airbags will be fully functional. If it doesn't, the code should give a clue as to what is the fault. Sounds like a seat belt tensioner fault but I can only guess.

I tried connecting up the diagnostoc computer but it wouldn't even power up. I traced that to a blown 7.5amp fuse in the boot. Connected back up and ran the tests. This is what I got. 'The squip for pyrofuse 'on-board electrical network line' has a malfunction. The electrical lines have a short circuit to each other.' I reset the fault code and it went away. I switched on the ignition again and it came back! Starting to look like a dealership fix!

 

[markjay]

The pyro fuse is part of the module on top of the positive battery connector. You may have caused a short circuit somehow when replacing the battery....

 

[Gozoman]

The pyro fuse is part of the module on top of the positive battery connector. You may have caused a short circuit somehow when replacing the battery....

That's what I was thinking. I'll have a look at it tomorrow if the rain stays off and see if I can spot anything obvious otherwise it will be back to the dealership for a no doubt costly repair!

 

[Chrishazle]

Try fuse 16, that's the one Halfords fried for me when they put a small car battery on the OBD port to change the main battery on my C220. Diagnostics would not work, fuse 16 blown was what it was traced to. It also did something to the secondary power supply to the transmission control module locking the gearstick in P, meaning we had to use the emergency release below the gearstick to get mobile!

 

[Gozoman]

Try fuse 16, that's the one Halfords fried for me when they put a small car battery on the OBD port to change the main battery on my C220. Diagnostics would not work, fuse 16 blown was what it was traced to. It also did something to the secondary power supply to the transmission control module locking the gearstick in P, meaning we had to use the emergency release below the gearstick to get mobile!

I already found the fuse in the boot and replaced it to get the OBD2 powered up again. I think the problem lies withn the pyrofuse on the positive battery terminal. When I took it off the blue, black, yellow connector on the side was broken. Perhaps that is what is being referred to as the 'squip''. I repaired it as best I could but maybe not well enough. I'll have a look tomorrow if I get the chance and the weather holds up.

 

[steveskeggy]

Are you sure it is "squip" and not "squib"?
It looks like that yellow connector, like an airbag connector, is shorting out inside, or it could be shorting out inside the red box.
You can get repair kits for the connector from MB main dealer, according to WIS (In reality it may be a different matter).
But, to tell you the truth, I would just get in touch with a Mercedes breaker, give them the part number of the red box (I think it starts N 000 000), and just swap it over, make sure they give you the yellow plug, and a big chunk of wire with it.
There is a page on how to repair the wire and plug in WIS, but basically it says cut the wires, and solder on replacement wires of the same length with the plug on the end (Obviously disconnect the battery, or batteries first).
You could go to the main dealer, but you would likely need to mortgage your house and sell your children to pay for it.

 

[Gozoman]

Are you sure it is "squip" and not "squib"?
It looks like that yellow connector, like an airbag connector, is shorting out inside, or it could be shorting out inside the red box.
You can get repair kits for the connector from MB main dealer, according to WIS (In reality it may be a different matter).
But, to tell you the truth, I would just get in touch with a Mercedes breaker, give them the part number of the red box (I think it starts N 000 000), and just swap it over, make sure they give you the yellow plug, and a big chunk of wire with it.
There is a page on how to repair the wire and plug in WIS, but basically it says cut the wires, and solder on replacement wires of the same length with the plug on the end (Obviously disconnect the battery, or batteries first).
You could go to the main dealer, but you would likely need to mortgage your house and sell your children to pay for it.

Thanks for that. I'll check out WIS first and see what I think.

 

[Gozoman]

Just an update on this problem. The squib is indeed the little connector on the positive battery terminal and it has a short inside. I took it up to the dealership yesterday and had it replaced and all is well again.