Control Module: Description and Operation

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

OPERATION
To prevent driveability problems, the Transmission Control Module 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 TCM switches a signal ON to the Damper Clutch Control Solenoid Valve to engage the torque converter clutch.