Operation CHARM: Car repair manuals for everyone.

ECM Signals

This signal is sent from transmission control module as a battery voltage signal only when A/T is in "R", "D", "2" or "L" range. Thus, ECM judges whether A/T is in one of the above range or otherwise (i.e. in "P" or "N" range) and uses it as one of the signals to control the fuel injector, idle speed control valve and ignition control.