AT-9 A340E(Others) AUTOMATIC TRANSMISSION - OPERATION 4. ELECTRONIC CONTROL SYSTEM The electronic control system, which controls the shift points and the operation of the lock-up clutch, is composed of the following 3 parts: 1. Sensors These sensors sense the vehicle speed, throttle opening and other conditions and send these data to the ECM in the form of electrical signals. 2. ECM The ECM determines the shift and lock-up timing based upon the signals from sensors, and controls the solenoid valves of the hydraulic control unit accordingly. 3. Actuators These are 3 solenoid valves that control hydraulic pressure acting on the hydraulic valves to control shifting and lock-up timing. SENSORS ECM ACTUATORS Throttle Position Sensor ESA • Idling Signal IDL ECM • Throttle Position Signal VTA Igniter ECTS THW Ignition Timing IGt Ignition Coil Control Distributor IGf Distributor • RPM Sensor Ne • Crankshaft Angle Signal G1, G- Spark Plugs No.1 Vehicle Speed Sensor SPD TCM S1 No.1 Solenoid Shift Timing Valve No.2 Vehicle Speed Sensor SP2 Control S2 No.2 Solenoid Valve Park/Neutral Position Switch NSW • Neutral Start Signal Lock-Up Timing SL No.3 Solenoid • Shift Lever Position Signal 2, L Control Valve Stop Light Switch STP Self-Diagnostic OD2 O/D OFF O/D Main Switch OD2 System Indicator Light ( Diagnostic Trouble Cruise Control ECU OD1 Back-Up System Code Display ) Battery +B V05023