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Join Date: Sep 2004
Location: Coventry, CT, USA
Well, you're on to something there. That looks like a Transistor, some kind of FET, or an SCR, but you need to see a part number on it to be sure. You'd think a simple Transistor given the function. You can check it with an ohm meter, but it may need to be desoldered to do it depending on the circuit. I'd see if it could be checked without desoldering first.
The middle leg is not connected as the metal backing attached to the board is the same point electrically. You could "probably" check across the two outer pins with your meter in diode mode. If you get a short both directions, probably a bad sign! Without a PN, you're guessing, however.
Edit: Thinking about this further, if you are motivated to start desoldering components to investigate your ECU's board, I'd say try the chip first! Chips are all over eBay for little money. I have that ST4 chip and have tried to sell it a few times. You can't give the things away. There's a guy on eBay from Slovakia that sells Ducati Performance chips. Certainly they are copies, but I've used one and they do work fine. ECUs are pricey and getting harder to come by. It could be the ECU, but I think I'd error on the side of the chip first. Whatever hardware is on the board to trigger that injector, it is controlled by the chip.
2001 900SSie (gone, but not forgotten)
2003 ST4s (The Truck)
1995 916 (Junk Yard Dog)
Last edited by SS904; Jan 12th, 2017 at 7:10 am.