Control Module: Description and Operation

Description

Funtion of TCU
1. Shift control and L-up control
According to each shift schedule, TCU sends signals to the S1, S2, S3, S4, SR, SL1, SL2 which operates control "Shift Control" and the SLU which operates linear control "L-up Control" on the basis of the vehicle speed and the throttle opening.

The TB-60SN and TB-65SN have a "AUTO CRUISE MODE" switch. Other mode does not have a driving mode selector switch that allows drivers to select a mode themselves. The vehicle is ordinarily in Economy mode. However, when specific conditions are met, the TCU selects a shifting pattern appropriate to driving conditions from all of the shifting patterns and switches automatically.

A. ECONOMY MODE
Used during normal driving. ECONOMY mode is basic shift schedule and the ideal shift schedule to be consistent with fuel economy and acceleration performance. This mode is normally selected where no other higher priority shift mode is activated. Full shift schedule map is available including lockup for this mode.
B. HIGH OIL TEMPERATURE MODE
This mode is protect the gearbox from the overheating. This mode is activated where the T/M oil temperature is too high, and will prevent the T/M oil temperature increasing by torque converter slipping. HIGH OIL TEMPERATURE MODE shift schedule map is available including lockup depending on the T/M oil temperature area for this mode.
C. UP SLOPE MODE 1, 2
The UP-SLOPE 1, 2 detect up hill road condition and change the shift map to powerful map to avoid busy shifting at up hill condition. When start condition of upslope mode is detected, shift map is changed upslope1 or upslope2 map depending on slope gradient if no higher priority mode is activated.
D. AUTO CRUISE MODE
The AUTO CRUISE CONTROL detects "ACC ON" signal and use specific point to prevent shift hunting during ACC ON. When cruise control is ON, gears are fixed to perform smooth driving.
E. GEAR HOLD MODE
The GEAR HOLD according to the request by TCS/VDC in order to support the vehicle stability. This function can be activated in every shift mode except for MANUAL MODE. When start condition is fulfilled, gear is held to current gear. The gear hold is performed after shift control finished if start condition is fulfilled during shifting.
2. Sports mode
Driver oneself can select favorite gear and enjoy sports driving of manual transmission sense by shifting shift lever from "D" to manual gear position and shift gate or steering switch M+(Up shift)/ M-(Down shift). But L-up control is operated automatically. Shift control is operated again by shifting from manual gear position to "D". Following control is operated when Sports shift mode.
3. L-up control
Based on rpm signals, signals from the engine control unit (engine rpm and throttle opening) and vehicle speed, smooth lock-up control is achieved through linear control of the lock-up control solenoid (SLU).
4. L-up cut control
This control cuts L-up operation at shift down or idle condition and avoid engine stall by depressing brake pedal at low speed driving.
5. Inhibit 5-6 shifting (low engine temp)
When engine water temperature signal detects cold, TCU prohibits 5-6 shifting.
6. Torque reduction control and line pressure control
This control improves the shift quality due to sending torque reduction request signal from TCU to PCM and cutting engine torque increase of shift at 1<->2<->3<->4<->5<->6.
Line pressure control improves the shift quality due to controllable line pressure at 1<->2<->3<->4<->5<->6.