Airbag ECU

A low voltage fault should be easily reset without removing the control unit.

The part you took out is the inflater.

 

Dealers dont generally fix cars over the phone. There are multiple sets of software in the Ferrari diagnostic units. Their use is not interchangeable. There were 2 different manufacturers involved. In our system if it is a battery voltage error it can be erased by the push of a button.

There is no Fiat setting on the correct equipment.

 

What exactly is a "low voltage"? Wouldn't every flat battery cause an airbag light? Or is there some capacitor in the ECU not holding a charge?

 

Low voltage usually results in the uninitiated jumping her, and that gets you the light. With luck an SD2 can reset it.

 

When the capacitor goes bad it illuminates the ECU fault and it cannot be turned out. Thats when you need an ECU.

 

As you would expect, but what is "low voltage"? A capacitor defect or a resettable glitch? Why is the "low voltage" being latched in memory?

 

When the car is first started the ECU charges the capacitor. It is very vulnerable at that point. It has been pointed out to me by electrical engineers that with starter load on a low battery and possibly the release of the starter there is a voltage spike. That spike can kill either the capacitor itself or its charging circuit. In my opinion and experience that is the primary cause of ECU failures. I did it once myself on a 355. Good news was the car was still under warranty.

In those cases where a car is started with low voltage it can set the low voltage error. I suspect that was done in an attempt to prevent ECU damage.

Since so many Ferraris on any given day have compromised batteries it is a common problem.

 

Resolved here:

https://www.ferrarichat.com/forum/threads/airbag-ecu.676338/

 

Just a few days ago I reset a low battery fault in a grey market 550 with the SD2. No trouble at all. Didn't take the car apart and didn't sen anything to England.

Do not understand the problem.