Fuel Trims Reset Everytime I Turn Off the Car

[johnk]

I was thinking about this problem my car is having and thought that maybe there is a switched power and constant power wire for the ECU kind of like a stereo setup has. Does anyone know if this is true and witch pin on the harness it would be? The car runs fine and doesn't show any other signs that the ECU is bad. No leaky caps they have been long since replaced.

 

[steve]

I was thinking about this problem my car is having and thought that maybe there is a switched power and constant power wire for the ECU kind of like a stereo setup has.

There is. Backup power is supplied on Pin 103 from the 10A room fuse #19. Same one that provides power to backup the radio.

It's not uncommon for this circuit to be damaged by C106 leaking but that should also disable the ECU from turning on. Sounds more like something funny with the wiring. You should have 12v at Pin 103 all the time.

Steve

 

[johnk]

OK my radio and interior lights still do work normally but I will check the voltage on pin 103 and get back.