CVT Control Description

Gear Ratio Control 

In order to achieve the optimum gear ratio for the driving force in accordance with the vehicle operating conditions, TCM detects vehicle conditions based on vehicle speed or input signals such as an accelerator pedal position.

TCM selects the optimum gear ratio and determines the gear change steps based on each input signal. By outputting these command signals to the stepper motor, TCM controls the line pressure to the primary pulley, decides the adjustable pulley position of the primary pulley, and controls the gear ratio.

Lock up control: 

When the vehicle speed exceeds the specified value, the TCC solenoid valve completely engages the TCC upon control signal from TCM. This control helps to improve the transaxle efficiency.

Slope shift control: 

TCM distinguishes uphill or downhill according to vehicle speed, accelerator pedal position and/or brake pedal position, and controls gear ratio as follows:

• Uphill: To improve acceleration, gear ratio in the high speed range is limited.
• Downhill: To obtain effective engine brakes, gear ratio is downshifted.

Garage shift control: 

If the select lever is shifted from "D" to "R" range while the vehicle is running at a specified speed or higher, TCM controls the transaxle operation and automatically shifts the transaxle to neutral in order to protect CVT inside parts from damage.

Manual mode control: 

When the select lever is shifted to "M" position, or when the shift paddle switch is operated with the select lever in "D" range, TCM switches the control mode from automatic mode to manual mode, while maintaining the actual gear ratio.

In manual mode, every time the paddle-up switch, paddle-down switch, shift-up switch or shift-down switch is turned on, TCM selects the predetermined gear ratio for 1-speed to 6-speed, and performs shift up or shift down depending on the vehicle speed.