550 Maranello Airbag ECU - Solved

I managed to solve the Airbag issue on the 550.
Symptom: Airbag light on that can not be cleared by ECU Scan or SD.

Cause: Airbag ECU capacitor (1 of 3) broken. If you look carefully you will notice a "bulge" on the capacitor. That is not normal.

Solution replace with a 550 Maranello ECU new or secondhand or cheaper replace with a Alfa Romeo 145/146 ECU (plenty on ebay).

You can query the 550 ECU by using a multiscan ECU tool set to Alfa 145 (Version TRW MY97 2F). If the scan is not able to communicate it means the ECU is dead. You can clear error codes and crash data once you are in. No need for a SD

All this is valid for EURO 550 but I am sure it works just as well with US versions.

The airbag ECU can be found between the seats. Best to remove them for clear access. Disconnect battery (+ and -) before dissasambly.
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Thanks for sharing this info. Hope I never have to do this on my car though.

 

Did you try swapping out the burned capacitor to see if that would fix your old one?

 

I am not brave enough ;o)

But with Alfa 145 ECU's going between 18 and 48€....

 

I need to try this. Can you give me the brand/model of the multiscan tool that you can use to query an Alfa airbag ecu??

 

Any brand will do.

If you go to a multi-brand garage they have a multi-scan tool.

I do not think you can get away with the 50 dollar scan tools they are just too limited and the Alfa is an old dog.

Look into the tool under Alfa (Fiat Punto is also ok). If you find the 145/146 you are in business.
My guess is that a 148 is also ok.

Next look for Airbag. You need the TRW MY97 2F version.

This means manufacturer TRW Mid Year 1997 model version 2 Front airbags.

If you are in the US high likely your Airbag ECU is wired to the ODB2 port. Lucky you.
If you are in Europe the Airbag Ecu is not wired to the OBD2 but is seperate.

You can find the three pin Airbag ECU in the pax footwell behind the footboard or tucked away behind the glove comparment. It is a fat yellow sleeved cable with a three pin connector. You will need the FIAT to OBD2 connector on ebay 10€ a piece.

No need for power to the car, the multiscan will power the airbag ecu.

If you can query the ecu you are in luck. Just reset and done.

 

Everyone loves a happy ending.

Congratulations and thank you for sharing.

 

Ah! I understand. Thank you. I know a couple of people that run garages and have such a multiscan tool. I thought you meant something specific to fiat... kind of like the Durametric system I have for my Porsche cars.

My 550 is a euro spec, but it has been converted to meet some US regulations and I know some obdii conversion was done as well. Hopefully I can communicate with the airbag ecu via the obdii port.

I'll keep you posted.

 

No nothing FIAT specific. If you are not on obd 2 you need the odb2 to three pin converter. It does not need to be Fiat specific, VAG group convertors also work.

You could also insert the airbag ecu pins in the obd 2 connector under the steering wheel but the original wire is too short...so a total faff.

 

Do you mean something like this:

Multiecuscan - Diagnostics software for Italian cars

used with this:

Multiecuscan - Diagnostics software for Italian cars


Found this on eBay. Looks like what I need to use the Multiecu Software:

http://www.ebay.com/itm/MultiECUScan-Scan-3-Pin-KKL-VAG-OBD-Engine-Airbag-Alfa-145-146-155-Fiat-Punto-/271566509189?hash=item3f3aa01485:g:EFoAAOxyRhBS2~AF


Can you tell me the exact fiat airbag ecu part number you had success with? I see so many on eBay and they all look a little different, so I don't know which one fits the 550 Maranello.

 

Many systems even in the US models prior to 360 were not connected to the OBD2 plug. Except for Motronic I don't even bother trying. I just go straight to the ALDL plug for all other systems.

 

Yeah, I was thinking I'd just go straight to the 3-pin connector using the above Vagcom w/ 3-pin obdII adaptor... if I can find it (I understand it's either behind the glovebox or in the passenger footwell area

I just saw this in the GREAT cross-referencing thread:

http://www.ferrarichat.com/forum/145087329-post276.html

So TAZ answered my question of "which Alfa ecu part no."

First I'm going to get the Vagcom/adaptor stuff (cheap enough) to see if I can query the airbag ecu at all. If I can, I'll just attempt to clear the faults. If I can't, I'll spring for the Alfa 145 /146 ecu (about $40 on eBay) and see what happens.

 

Here you go


Airbag Steuergerät Airbagsteuergerät Alfa Romeo 145 | eBay

You even get a discount

Do not forget to pull the Ferrari sticker from your old one and stick it over the Alfa one. If you do not the ECU will not work ;o)

 

Hello. Before I get started, I see a very fat yellow cable just behind the glovebox. It seems to be strapped away very well and follows a raceway parallel to the glovebox, but I see no connector. Is it possible that I must pull the passenger side footwell trim, because the cable seems to run from behind the glovebox to behind the carpet trim.

Thanks.

 

Yes that is it. If you remove the footwell carpet you should get the cable. It is actually a yellow jacket I think the cables are red and brown or something like that.

You should see a 3 pin connector but with only 2 live cables.

If I remember well it was zip tied away as well.

 

Great! Thank you. I didn't want to remove the footwell carpet unnecessarily

 

Is there any chance this process will set off the airbags

thx

 

Whenever working on the airbag system, use the vehicle battery cutoff switch AND it's also recommended that you wait for the ECU capacitors to discharge. I haven't found any specific times, but I'd wait an hour or two.... or overnight if you're the nervous type