System Functions

System Functions





'J' Gate Layout

Range Selection
The 'J' gate selector lever is connected to the transmission via a cable which operates the transmission selector shaft between positions P R N D only. The shift lever disconnects from the cable when the lever is moved across the gate from D to 4.
Movement of the lever between P R N D manually controls the flow of transmission fluid, the TCM having control of the forward gear selected in D.
Movement of the lever to 4, 3 and 2 positions does not manually modify the fluid flow, the TCM detects these positions using the DLS and controls the ratios electronically by energizing solenoids.

Shift Point Control
The gearshift points are controlled by the TCM, as a function of the output speed, engine load, engine speed selector position and shift program selected. The operator has control over the shift points via the shift lever, throttle pedal movement, kickdown function and mode switch.

Mode Switch
This switch allows operator selection of two base shift modes, Normal and Sport, the switch being illuminated when Sport is selected. This function alters the values in the TCM shift point calculations.

Shift Programs
Upon encountering the following conditions, the TCM will automatically modify the Normal or Sports shift map to enhance the operation of the vehicle:
1. Traction: When traction intervention is active.
2. Hot mode: Extreme engine/transmission temperatures.
3. Gradient: Under specific speeds and loads.
4. Manual: Driver initiated override of the normal shift map when the LH side of the 'J gate' is used.

Traction
When traction or stability control (engine or brake system derived) is operational the TCM will implement the traction map to maximize control of wheel slip.

Gradient
The gradient function is intended to enhance vehicle driveability when climbing a gradient or towing. The TCM will implement the function when increased driving resistance is detected, and provides enhanced driveability, additional cooling and/or increased performance as appropriate.

Serial Communications Interfaces
Controller Area Network (CAN)
The TCM is an integral part of the CAN system which facilitates the interchange of real-time data between control modules and sensors; refer to Powertrain Management for a full description of CAN.