TORQUE CONVERTER CLUTCH (TCC) CONTROL OPERATION [FN4A-EL]
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TCC Released
• By sending an OFF signal to the shift solenoid E, the solenoid reducing pressure is drained and the TCC control valve is pushed to the right by the spring force.
• As a result, the TCC piston is released because the torque converter pressure acts the torque converter front chamber.
TCC Engaged
• By sending an ON signal to the shift solenoid E, the solenoid reducing pressure acts right side of the TCC control valve and push it to the left.
• Simultaneously, the TCC piston engagement pressure is drained gradually by increasing the signal of duty ratio (50 Hz ON time ratio) to shift solenoid A gradually.
• As a result, smooth TCC operation is possible because the TCC piston is pressed smoothly to the torque converter cover by draining pressure in the torque converter front chamber gradually.
Determination of TCC Inhibition
• The TCC control is inhibited when any of the following conditions are met:
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― ATF temperature is low
― Accelerator pedal is released
― Accelerator pedal depressing speed and accelerator pedal depressing amount are above specified value
― Brake pedal is depressed
― Engine speed is low
― Engine coolant temperature is low
― DTC is detected
