Control Module: Description and Operation

The Transmission Control Unit (TCU) calculates transmission speed and gear ratio based upon input signals from Pulse Generators A and B. The TCU controls the torque converter damper clutch based on the input operating conditions.

To prevent driveability problems, the Transmission Control Unit turns the damper clutch OFF under the following conditions:

- First and reverse gears- To secure quick acceleration at start
- Below approximately 800 RPM- To secure easy start
- Large throttle opening at engine speeds of 2,000 RPM or less- To secure quick acceleration
- Engine braking- To prevent deceleration shock
- 3-2 downshift- To secure shift feeling
- Engine coolant temperature below 122°F (50°C)

If all operating conditions are correct, the TCU switches a signal ON to the Damper Clutch Control Solenoid Valve to engage the torque converter clutch.