Control Module: Description and Operation

PURPOSE
The Transmission Control Module (TCM), based on predetermined shifting characteristics and lockup operating valve, provides optimum shifting control across the range of vehicle operating conditions.

OPERATION
The following input signals are sent to the TCM: select lever position from the mode switch, running mode from the power and winter switches, throttle opening from the throttle position sensor, vehicle speed from the vehicle speed sensor, and engine rpm from the ECM. After receiving these signals, the TCM determines vehicle running condition and sends output signals to each solenoid to control shifting.

- When the TCC solenoid is engaged, the lockup mechanism operates.
- Shift solenoids 2/3 and 1-2/3-4 select shift gear position.
- The force motor controls line pressure to improve shift feel.
- When the TCM detects an abnormal signal, it causes the CHECK TRANS lamp on the instrument panel to flash, alerting the driver to a malfunction.