I would check behind the kickplate on the passenger side below the glovebox... I know that it is that way on the 80's Toyotas until '89. Other than that I haven't worked on anything newer...If I were you I would check to see that the weather seal around the windsheild wasn't bad. If it were it might allow condensation to follow down to body to the ECU. But then again that theory is based on the assumption that I have the correct location of the ECU.