Electronics

The powertrain control module (PCM) (12A650) and its input/output network control the following transmission operations:

• Shift timing.
• Line pressure (shift feel).
• Torque converter clutch.

The transmission control is separate from the engine control strategy in the PCM, although some of the input signals are shared.

The powertrain control module receives some input signals from engine-related sensors:

• Mass airflow sensor (MAF sensor) (12B579) .
• Engine coolant temperature sensor (ECT sensor) (12A648).

These signals provide information to the powertrain control module about the load and climate under which the engine is operating. Some other inputs are based on driver inputs, such as accelerator pedal position which is related to the powertrain control module by the throttle position sensor (TP sensor) (9B989). Still other inputs are provided by:

• Transmission components.
• Output shaft speed sensor.
• Manual lever position sensor (controlled by driver placement of the shift lever).
• Transmission oil temperature sensor (TOT sensor) (7H141)

Using all of these input signals, the powertrain control module can determine when the time and conditions are right for a shift or torque converter clutch application. The powertrain control module can also determine the line pressure needed to optimize shift feel. To accomplish these functions, the powertrain control module controls four electronic solenoids:

• Two On/Off shift solenoids (7G484).
• One pulse- width modulated torque converter clutch solenoid (TCC solenoid) (7G136) for torque converter clutch (TCC) control or "controlled slip" of the torque converter clutch.
• An electronic pressure control (EPC) solenoid for line pressure control.