SSANGYONG REXTON 2006.09 Manual page 724

0-18 3110-01
(3) CIRCUIT DESCRIPTION
A. 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.
▶Shifting Method
Basic shift operation includes up-shift and down-shift for all gear groups. The 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.
▶Down Shift
When engine speed increases excessively, the down shift does not occur. To get an
engine brake effect during downhill driving, the current gear is maintained in speed control
mode.
▶Engine RPM Adjustment
During shifting, the engine torque is reduced to optimize the shift operation by delaying the
ignition time.
▶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.
▶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.
CIRCUIT
REXTON 2006.09
B. MODE SWITCH
▶Function
The mode switch is installed beside the selector lever and it has two modes of "S"
mode (Standard Mode) and "W" mode (Winter Mode).
- "S" mode is used in normal driving (starts off with 1st gear). TCU (Transmission
Control Unit) provides pleasant driving by changing the shifting pattern according to
the driving habits (downhill gripping: approx. 11 ~ 13.5 %)
- When "W" mode is selected, the Winter mode indicator in meter cluster comes
on, and the vehicle starts off with 2nd gear to achieve smooth starting on the icy or
slippery road.
In winter mode, the up shift becomes faster and the down shift becomes slower for
improving fuel consumption. The "W" mode is automatically changed to "S" mode in
full throttle or kick-down operation. The vehicle can starts off with 2nd reverse gear (gear
ratio: 1.92 ~ 1.93) when the "W" mode is selected. It is very useful on icy and
slippery road. However, in this case, the "W"
placing the selector lever to "R" position.
Even though "W" mode is selected, the vehicle starts off with 1st gear in following:
When the system recognizes the mode switch operation, the selector lever control unit
sends the control signal TCU via CAN communication.
- When the selector lever is in "1" position.
- When fully depressing the accelerator pedal or when starting off with kick-down
condition.
switch should be selected before