Created By:	Frank Mitchell	Category:	ECU / Computer / Diagnostics
Date Posted:	02-20-02	Views:	4197
Title:	ECU Clearing
Article:	Basically, you just unhook the battery for a few minutes and it clears off the ECU. I have heard people talk about pulling the fuse to the ECU, which works also. I'm real simple when it comes to this, I would just pull a battery terminal off and I know I have the right one and that there is no possibility of electricity getting past a disconnected terminal. The idea is that the computer adjusts its parameters to meet the requirements of the car as reported to the computer by the sensors in the engine. Knock, O2, intake air temp, mass air pressure, etc. So the car has the ability to adjust from its basic program to the individual requirements of the car, regardless of if those requirements are because some piece of the car is not working correctly (to compensate) or if the driver knows only two settings for the controls, those being full throttle and full brake. The computer stores these and by cutting the electricity, it erases the adjustments and it starts back in a learning mode that runs rich for safety and adjusts itself to meet the parameters it sees as the car is driven, leaning back the mixture until it is within spec. The idea of leaving it unhooked for a amount of time is because they will put a capacitor in the line to keep the voltage constant and keep the computer from erasing the adjustments if the line is interupted for a short period of time. To erase the adjustments, it would have to be unhooked long enough to drain the capacitor of its charge. I don't think that time requirement is a half hour, or more than a few minutes, but keeping it unhooked longer isn't going to hurt anything and better safe than sorry. this information supplied with permission from Bill Luton