AIRBAG ECUs DEFECTIVE!

I need to find the wiring diagram for the connector.

Here are some Photoshopped pictures to help with following the traces.
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If they actually eliminate any spark when the last connection is made I would sure think they must be doing something (and likely something beneficial). The price certainly seems reasonable.

The simple fact that they will "save you" from incorrect polarity connection makes them worth every penny, and then some, in my book (even if they did nothing else). What does in cost to get the diodes replaced in an alternator? What about serious acid burns or worse if you're jumping a typical car, where the battery is not hidden in the wheel well, and it explodes from reversed polarity?


http://www.amazon.com/Michelin-5100-.../dp/B002RRZX06

 

NICE work guys!!!! Great thread here...I never even knew this was an issue. Now I'll make sure the battery is charged good before trying to crank it over.

 

never seen surge protection for a car. How does it work? Something you made or something you bought?

 

they've been around for some time but you don't really hear about them:

http://www.zips.com/Store_Products.aspx?CAT=129

http://www.summit-equipment-outlet.com/work-truck-equipment/jump-start-equipment/surge-protectors-surge-protection-and-battery-protectors.html

http://www.ntxtools.com/network-tool-warehouse/OTC-3386.html

 

That's pretty cool. But, who has tested it in their Ferrari to see if it doesn't blow an ECU when your low on battery and need to jump.

Have you had to jump start since you put it in? Anyone?

 

I tried to lookup the Airbag ECU in the 355 schematics. Of course, it's not listed. The airbag light is, and it will take time to trace it with all the page-offs.

I love how some items are listed in the Italian legend but not the English. Those Italians, they have such a sense of humor.

I did some research. The official term is ACU (airbag control unit) but ECU works too and TRW makes them, but their newest one only resembles this one but is obviously a later rev. I couldn't find info on their older units. None of the PCB designators match anything.

I did find ACU repair guys. Just google "Airbag ECU repair". And several will pop up. I didn't see any American ones though, liability?

That made me think deeper about this.

It might be fun to figure out what went wrong for that knowledge, but we don't have an "ACU tester" so once we repair it we will not know if it will work properly and under all conditions.

Plus, who wants to plug this sucker in after it has been "repaired - IE the light is off" and have it fire an airbag inadvertenly.

And, you can't sell it on eBay either since you will have liability if it does something bad.

Maybe its best to leave the repair to companies that have the experience, and the test protocols for it.

One interesting thing I saw, was a reference that because of the high price of ACU's they are being keyed to the car to prevent theft. I don't know which cars this applies to.

Lets get the part# for the regulator and see what it is.

 

I cannot say if they work or not. I do suspect they are very simple inside and probably use components that cost very little (big profit margin). It's a small amount of money (if it works) versus the price of any ECU. I know some people that weld on cars use them and others say just disconnecting the car battery is fine. Could be snake oil..... don't know for sure. I'm pretty sure you're not going to find anyone willing to purposely test it on their Ferrari.

 

I'm pretty sure your right.

 

Apparently my soldering iron isn't powerful enough to overcome the heatsink, so I need to buy a more powerful one. More later...

 

A thought from a non-electronic guy.

Would it be possible to put a delay in the air bag ECU power supply so that it wouldn't be powered until maybe 5-10 seconds or so after the car has started and the battery voltage is stable?

Something like this maybe
http://www.elecfree.com/electronic/power-on-delay-circuits-by-555/

 

Its too bad TRW didn't hire someone like you to be part of the design team. Makes complete sense to me.

 

Or maybe have the air bag ECU powered via a relay with the relay activated by the speedometer sensor. If the speedo sensor signal is powerful enough to activate a relay it could be done with a relay and two diodes.

That way the air bag ECU would be powered up when the car first moved and stay powered until the key was turned off.

 

All of these are good ideas, after the fact. If they had known the cause of the problem, they would have designed a simple time delay circuit to solve it. Ferrari with its small volume would not have tried to go back and clean up the problem after production, especially when the problem results in more money for them.

 

It appears this is a TRW ACU and would be destined for more cars than just Ferrari. It's to early to say it is not Ferrari influenced, but it wouldn't surprise me to hear that this ACU was not specially designed for Ferrari.

 

Understood. And has been noted, just protecting against sparks/reversed polarity is "progress".

I'd just like a "definitive" answer to the "will they protect my electronics? question - I'm guessing they could charge a small fortune if they offered a warranty covering any parts destroyed as a result of using 'em......

Cheers,
Ian

 

That ECU is used in MANY cars. Its programed differently for different applications. Trouble is, once you have repaired the thing, you still need the correct scan tool to clear the airbag light..in Ferrari's case the SD2.

IMHO, messing around with this thing is kinda dangerous. Lets say it works out for you, but a week later your driving along you favorite road in the middle of your favorite twisty section, and BLAM..off go the airbags, and your into a tree or worse!!

Tempering with an airbag system is HIGHLY ILLEGAL..in Canada anyway.

The other thing you MUST realize..DO NOT under any circumstances use a test light anywhere in the circuit. Use a high impedance meter to test the system.

I would buy the correct unit along with the updated harness from Ferrari, install it yourself, then take the car to the dealer to have it set-up and cleared. You'll be good for another 13 years..IF YOU DON'T BOOST THE CAR!!!!

 

Clearing the airbag light isn't such a big deal. It takes literally just a few minutes.

This ECU may be "like" other Airbag ECUs but lets be serious here for a moment. On Ebay all ECUs for airbags are typically $50-$60. Range Rover and E46 M3 ECUs listed at $99. I suspect new these ECUs are pretty cheap for most cars. If I could replace my ECU in the Ferrari for that cost level this wouldn't be an issue. However, the Ferrari ECU on Ebay is over $1200.

Also, I've owned and jumped BMW, Mercedes, Porsche, etc., and at one point or another jumped from a low or dead battery. Never blew an ECU. Two nights ago I jumped a neighbors C70 Volvo. No airbag light!

If this had been a GM or Toyota problem it would be all over the news! Unfortunately, most Ferrari owners bow down to Ferrari with lower expectations, as if Ferrari was doing them a favor by letting them drive one of their cars.

I wonder how NHTSA would view this problem. I think starting a car with a low battery, particularly a car not intended to be a daily driver, is to be expected. I don't think an ECU for a critical safety component should be acceptable given the existing government regs. I'll be calling NHTSA and the DOT on Monday.

 

OK- you guys have scared me enough to do something. I will certainly remember- but you never know what could happen so a simple 2" x 4" sticker on the battery and wheelhouse might stop a tragedy...
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Brilliant! Yes sir! Warning appropriate and failure to warn noted

 

If I were going to take a guess at what is happening...

I suspect that the battery acts like a heavy duty voltage regulator when it's charged and working correctly. If the battery is low, it doesn't, so when you crank the starter, which is a very high inductance, you generate high voltage spikes that aren't supressed by the battery and this is what kills the ACU. I suspect we could use some kind of capacitor or surge supressor like a transzorb on the voltage supply to this unit to keep this from happening.

Now as to what actually fried during the spike is up for another guess. Most modern electrical circuits, especially those designed for cars are set up to handle things like this. So I'm not sure why this is a problem other than maybe the battery location in relation to the starter and how they are wired. It just may be the chip is gone and the system essentially unrepairable.

 

Replaced 3 last year all in 355s and saw 2 more clients declined to replace putting it on buyer they were selling car to with the firm note air bag ecu needed replacing at $1700 plus R&R

 

While the ECU may be by TRW, the wiring to it, including the power surges caused by that wiring are pure Ferrari.

 

In general, I think Ferrari owners have shot themselves in the collective feet by not actually driving the stinking cars during the covered period. I mean, if people put 10k miles a year on them, think how many more things would be sorted before the warranty ran out?

Of course the guys buying them new are not the guys complaining now. They are too busy enjoying scuds and calis.

 

Along with a battery tender, get yourself a top notch battery too. The top rated battery from Consumer Reports is the Sears Platinum absorbed glass mat battery (AGM). Totally sealed, never needs water, will never leak electrolyte. It is an 880 cold cranking amp brute with a four year free replacement warranty. Only sold in a Group 34, it will fit in a 355, even though the terminals are not reversed like the oem battery. Fortunately the battery cables are long enough to reach anyway.

http://www.sears.com/shc/s/p_10153_12605_02850034000P

I believe this battery is made by Odessey.