The Project Pad

I had a spare 4A0 907 551AA ECU sitting on a shelf for around a year, this ECU worked before i shelfed it. i tried to use it today and i get no signal to the POS's. car is getting fuel as i can smell it too. i put the stock ECU back in my S6 and the car fires right up and drives fine so i rule out any sensors on the engine being bad. is there something common in the ECU that can crap out?

vwnut8392 wrote:I had a spare 4A0 907 551AA ECU sitting on a shelf for around a year, this ECU worked before i shelfed it. i tried to use it today and i get no signal to the POS's. car is getting fuel as i can smell it too. i put the stock ECU back in my S6 and the car fires right up and drives fine so i rule out any sensors on the engine being bad. is there something common in the ECU that can crap out?

Moisture is a big one - Was it in a dry storage? You could always check the pins for corrosion - IE bad ground.

Marc @ efi express would be to the dude to talk to.

its was in my office on a shelf where i keep all my ECU's at, i figured its the best place for them as its a climate controlled environment. i cant find a speck of corrosion anywhere in it either. when i have it hooked to a car i can access the ECU with VCDS and i get no fault codes as well other than that typical cam or crank sensor code that comes up when the car isnt running. i get a CEL when key on like i should, and it goes out when cranking. i pulled all my coils out and put spark plugs in them to see if theres a spark and nothing happens. i than moved to test the signal coming from the ECU to the POS's with my logic probe and there's nothing coming to the POS's. is there some sort of coil drivers inside the ECU that could go?

Yes the coil drivers are known to fail and no replacement has been found. Except for VEMS

i have a VEMS ECU sort of which im not very pleased with as its probably holding papers down or propping a door open at EFI express till i can afford to have it fixed.