Tcu (Transmission Control Unit) - SSANGYONG 2004 Rexton 2.7XDi Workshop Manual

TCU (Transmission Control Unit)

Function
TCU controls the gear groups according to the driving conditions. It receives the driving data from many sensors and
switches as input signals. It is also connected with ECU, HECU, instrument panel and selector lever control unit.
1. Shifting Method
Basic shift operation includes up-shift and down-shift for all gear groups. Shift control unit determines driving
resistance, accelerator pedal position, vehicle speed and some parameters (road surface condition, up hill and
down hill gradients, trailer driving conditions, catalytic converter conditions, driving habits and automatic transmission
oil temperature) to select a shift gear.
2. Down Shift
When engine speed increases excessively, the down shift does not occur. When driving down hill, the transmission
is quickly down shifted to 3rd gear to get an engine brake effect in speed control mode. This down shift is operated
when there is above 7 km/h difference from stored speed value and possible at below 125 Km/h.
3. Engine RPM Adjustment
During shifting, the engine torque is reduced to optimize the shift operation by delaying the ignition time.
4. Lock-Up Clutch Control
The lockup clutch in torque converter is activated in 3rd, 4th and 5th gear and operates in sequence via PWM
solenoid valve.
5. Others
The transmission is automatically controlled to compensate durability and wear.
The shift control values such as shifting point, shifting time, pressure during shifting, and lockup clutch control are
permanently saved and the diagnosis is partially available.
DC 5-SPEED AUTOMATIC TRANSMISSION
REXTON SM - 2004.4
3A1-43
Y220_3A1051
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN