Electronic Shift Control System

ELECTRONIC SHIFT CONTROL SYSTEM

Transmission Control Module (TCM)






The TCM is an electronic circuit component that controls gear shift and idle-up according to the signal from each sensor. It is a microcomputer consisting of an IC, transistor, diode, etc. It is installed at the right side of the steering column.

Throttle Position Sensor
This sensor is installed to the throttle valve shaft. Throttle valve opening signal is transmitted from Throttle Position (TP) sensor to Engine Control Module (ECM) as voltage signal. The signal is converted to duty signal in ECM and it is sent to transmission control module.

Vehicle Speed Sensor





This sensor is a pulse generator type that detects revolution of the counter driven gear (vehicle speed) in the transmission case.
The pulse generator is a noncontact sensor consisting of a permanent magnet, coil and gears.
As the gear of the counter driven gear rotor turns, the magneflux from the permanent magnet varies and a voltage of the frequency corresponding to the rotor revolution occurs in the coil. This voltage is inputted to the TCM where TCM judges the counter driven gear revolution or the vehicle speed.

Forward Clutch Cylinder Revolution Sensor (Input Shaft Revolution Sensor)





This sensor is a pulse generator type that detects revolution of the forward clutch drum (input shaft) in the transmission case.
The principle of operation is the same as the vehicle speed sensor but Transmission Control Module (TCM) detects the revolution speed inputted to the transmission based on the signal from this sensor.

Transmission Range Switch








A shift switch is provided so that the engine can be started only when the shift lever is in the "P" or "N" position.

Brake Switch





The same switch is used as the brake lamp switch. It disengages the Torque Converter Clutch (TCC) when the brake is depressed while the TCC is operating.

Engine Coolant Temperature Sensor (ECT Sensor)





The engine coolant temperature is detected by the engine coolant temperature sensor in the electronic fuel injection system and sent from Engine Control Module (ECM) to Transmission Control Module (TCM) as a signal. TCM uses this signal as one of the factors to control gear shift to the 4th (0/D) gear, Torque Converter Clutch (TCC) operation and throttle pressure.

O/D Cut Switch





The gear shift up or shift down to and from the O/D gear can be selected with this switch.

Cruise Control Unit (If Equipped)
Cruise control unit is also can be control the gear shift up or shift down to and from the O/D gear and lock-up when cruise control system is operating.

Fail Safe Function





This function is provided by the safe mechanism that assures safe driveability even when the solenoid valve, sensor or its circuit fails. The table shows the fail safe function for each fail condition of sensor, solenoid or its circuit.

Change Mechanism





The same select pattern shift lever is used as the floor type and frequently used "N" and "D" ranges are made selectable freely.


Automatic Gear Shift Diagram











Automatic shift schedule as a result of shift control is shown. In case that select lever is shifted to L at a higher than 41 km/h (26 mile/h) speed, 2nd gear is operated and then down shifts to 1st at a speed lower than that. No up shift is available in L. The same as, the select lever is shifted to 2 at a higher than 115 km/h (71.5 mile/h) speed, 3rd gear is operated and then down shifts to 2nd at a speed lower than that. No up shift is available in 2.