Control Module: Description and Operation

^ The EC-AT (Electronically Controlled Automatic Transmission) Control Unit, located under the dash left of the steering column, is the control unit for various electrically operated functions of the F4A-EL automatic transaxle.
^ One of these functions is torque converter lockup or lockup inhibit, activated according to operating conditions.
^ Control of ATF flow to the torque converter and lockup are achieved by EC-AT control unit energizing and de-energizing the transmission lockup solenoid. The ATF passage is closed when current is applied and open when current is cut.
^ To coordinate engine operating conditions with transmission functioning, the ECU sends a signal to the EC-AT control unit (an output from the ECU). The signal informs the control unit of engine coolant temperature, an input used to calculate lockup control.
^ Lockup is permitted during most driving conditions but specifically inhibited when the control unit receives a coolant temperature signal below 72°C (162°F).