The automatic transmission control unit is responsible for the operation of the pump, control valve, electromagnetic valves, hydraulic accumulators, locking clutches and brakes. The main pressure in the hydraulic system of the automatic transmission is created by the pump, it is regulated by the control system depending on the load and speed of the car and ensures the operation of the torque converter, locking clutches and brakes.
The shift valves control the flow of fluid into the torque converter and planetary gearbox.
The valve block has three solenoids that control gear shifting and torque converter lock-up.
Fig. 3.74. Electronic control system of the Mazda 3: 1 – HOLD mode indicator lamp; 2 – speedometer; 3 – brake light switch; 4 – PCM block; 5 – HOLD switch; 6 – throttle position sensor; 7 – DLC; 8 – mass air flow sensor; 9 – Engine coolant temperature sensor; 10 – vehicle speed sensor; 11 – turbine speed sensor; 12 – crankshaft position sensor; 13 – control valve (with transmission fluid temperature sensor and electromagnetic valves); 14 – Automatic transmission range switch; 15 – oil pressure sensor
Fig. 3.75. Block diagram of the Mazda 3 vehicle control system: 1 – RCM block; 2 – engine management system; 3 – gearbox control system in block with main gear; 4 – on-board diagnostics system; 5 – input signals; 6 – throttle position sensor; 7 – crankshaft position sensor; 8 – mass air flow sensor; 9 – Brake light switch; 10 – Engine coolant temperature sensor; 11 – Engine control output signals; 12 – communication channel connector; 13 – HOLD mode switch; 14 – turbine speed sensor; 15 – vehicle speed sensor; 16 – gearbox fluid temperature sensor in the block with the main gear; 17 – Automatic transmission range switch; 18 – oil pressure sensor; 19 – output signals; 20 – Switch solenoid A; 21 – Shift solenoid B; 22 – Shift solenoid C; 23 – Shift solenoid D; 24 – Switch solenoid E; 25 – pressure control solenoid; 26 – speedometer signal; 27 – HOLD mode indicator lamp