Shift Indicator - A/T: Description and Operation

This system electronically controls the gear shift timing, lock-up timing, the clutch and brake hydraulic pressure, and the engine torque during shifting, to achieve optimum shift feeling in accordance with the driving conditions and engine operating conditions, as detected by various sensors.

1. GEAR SHIFT OPERATION
During driving, the engine control module (ECU) selects the most appropriate gear for the driving conditions, based ON input signals from the engine coolant temp. sensor (EFI water temp. sensor) to TERMINAL THW of the engine control module (ECU), and also ONthe input signals to TERMINAL SP2 of the engine control module (ECU) from the speed sensor devoted to the electronically controlled transmission. Current is then output to the electronically controlled transmission solenoids. When shifting to 1st speed, current flows from TERMINAL S1 of the engine control module (ECU) --> TERMINAL 3 of the electronically controlled transmission solenoids --> GROUND, and a continuous flow to No.1 solenoid cause the shift.
For 2nd speed, current flows from TERMINAL S1 of the engine control module (ECU) --> TERMINAL 3 of the electronically controlled transmission solenoids --> GROUND, and from TERMINAL S2 of the engine control module (ECU) --> TERMINAL 1 of the electronically controlled transmission solenoids --> GROUND, and a continuous flow to solenoids No.1 and No.2 cause the shift.
For 3rd speed, there is no a continuous flow to No.1 solenoid, only to No.2. causing the shift.
Shifting into 4th speed (overdrive) takes place when there is no continuity to either No.1 or No.2 solenoid.

2. LOCK-UP OPERATION
When the engine control module (ECU) judges from each signal that lock-up operation conditions have been met, current flows from TERMINAL SL of the engine control module (ECU) --> TERMINAL 2 of the electronically controlled transmission solenoids --> GROUND, causing a continuous to the lock-up solenoid and causing lock-up operation.

3. STOP LIGHT SW CIRCUIT
If the brake pedal is depressed (stop light SW ON) when driving in lock-up condition, a signal is input to TERMINAL B/K of the engine control module (ECU), which operates, and the continuous flow to the lock-up solenoid is cut

4. OVERDRIVE CIRCUIT
^ O/D Main SW ON
When the O/D main SW is turned ON (O/D OFF indicator light turns OFF), a signal is input to TERMINAL OD2 of the engine control module (ECU) which operates and causes gear shift when the conditions for overdrive are met.
^ O/D Main SW OFF
When the O/D main SW is turned OFF, the current flowing through the O/D OFF indicator light flows through the O/D main SW to GROUND, causing the indicator light to light up. At the same time, a signal is input to TERMINAL OD2 of the engine control module (ECU) and it operates to prevent shifting into overdrive.