I was wondering if there is a way to reset the ecu on my truck? it's a 1992 F150 5.0 auto trans.

 

Disconnect battery for 10 minutes

 

Disconnect battery with the headlights on for 5 min or more

 

Disconnect battery with the headlights on for 5 min or more both terminals and do the negative first

 

what's the headlights on have to do with it ??

 

The theory with turning the headlights on drains the "stores charge" on the computer. Not sure if it actually does anything but I have always done it.

Wayne

 

Why exactly are you trying to reset on the ECU? If all you want to do is clear codes just disconnect one of the cables.

 

Think about it...if it worked like you said..after you disconnect the batt..you would be able to turn on your head lights til the power was gone... you really don't want to disconnect your batt with power being pulled from it.. ie...lights on

 

Pull both cables and do it with headlights on to be safe . It pulls everything off and resets so nothing's stored. I've done one cable and it cleard one code but didnt reset anything. If you pull both terminals and do it with the headlights on it completly resets the system. After you do it and turn the truck on let it idle for a little so it can relearn idle .

 

The headlights don't pull power from the ecu capacitors. They simply aren't wired that way. However pulling the battery cables with a high draw on it is unsafe and causes a flashback to the cable still connected. Modern electronics have diodes to prevent flashback but headlights don't. Just unhook the negative and leave out disconnected for 10 minuets per Ford tech information. The ecu will result to default and require a complete drive cycle to reset all parameters.