It's easily possible, i had this happent to me, the mechanic diagnosed the problem's i was having as water getting into the ECU now granted this wasnt my issue in the end but had it continued it would have been another issue, anyways what happens is the boot the wires go through on the passenger side door becomes disloged or just breaks up due to age this is turn let's water come in as it streams down the side of the car and drip in, at which point it drip's directly on top of the ECU, i found and easy cheap fix for this, i went out and purchased some high temp silicon, high temp low temp doesnt matter, i filled the hole on the inside completly with the silicone which in turn sealed the wires and everything around this, i used silicone as it would still give movement to the wires but continue to hold a seal.