TORQUE CONVERTER CLUTCH (TCC) CONTROL OPERATION [GF4AX-EL]
BUE051718880N29
TCC Engagement
• The PCM determines TCC engagement and sends an ON signal to the TCC control solenoid. The TCC shift valve is then pushed to the right due to spring force with no influence of line pressure. Due to this, the torque converter engagement pressure used in torque converter chamber F is released through the TCC shift valve, and the TCC piston is pressure-fixed against the converter cover effecting a complete TCC condition.
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1
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TCC piston
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2
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Converter cover
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3
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Torque converter chamber F
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4
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Oil cooler
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5
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TCC shift valve
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6
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TCC control solenoid
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7
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Solenoid reducing pressure
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8
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Torque converter pressure
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9
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Line pressure
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TCC Release
• The PCM determines TCC release and sends an OFF signal to the TCC control solenoid. The TCC shift valve is then moved to the left by line pressure acting on the right side. Due to this, the torque converter engagement pressure is not released, but flows from the torque converter engagement chamber to the torque converter release chamber, the TCC piston disengages from the converter cover and TCC is released.
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1
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TCC piston
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2
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Converter cover
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3
|
Torque converter chamber F
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4
|
Oil cooler
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5
|
TCC shift valve
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6
|
TCC control solenoid
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7
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Solenoid reducing pressure
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8
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Torque converter pressure
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9
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Line pressure
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TCC Driving Inhibited Determination
• TCC driving is inhibited according to engine load conditions to improve driveability.
• If any one of the following conditions is met, TCC control is inhibited.
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- Engine speed is less than set value
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- Coolant temperature is less than set value
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- Brake switch is on
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- Not within TCC range
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- Accelerator opening angle is more than set value