DESCRIPTION
Automatic transmission is electronically controlled. Transmission shifting and torque converter lock-up are controlled by Powertrain Control Module (PCM). The PCM receives information from various input devices and uses this information to control shift solenoids, band apply solenoid and Torque Converter Clutch (TCC) solenoid. The PCM uses input signals to control pressure control solenoid (force motor) operation, which operates the pressure regulator valve to control line pressure.
A torque management control system is used. The PCM uses a torque management control system to deliver a spark advance signal during transmission shifting. This controls engine torque and reduces engagement shock caused by a change in vehicle speed.
The PCM contains a fail-safe system. When a failure or problem is present in the transmission electronic control system, the PCM may go into a back-up mode using pre-programmed values, allowing vehicle to be driven. The CHECK TRANS light on instrument panel will flash to inform driver of a problem. Vehicle can be driven, but shifting must be done manually. For additional information, see POWERTRAIN CONTROL MODULE (PCM) under OPERATION.
Transmission is capable of 3 different shift modes, Normal (NOR) mode, Power (PWR) mode and Winter mode. For additional information, see SHIFT MODES under OPERATION.
Transmission is equipped with shift and key lock systems. Shift lock system prevents gearshift lever movement from "P" position unless brake pedal is depressed, ignition is on and release button on gearshift lever is depressed. Key lock system prevents ignition switch from being placed in LOCK position unless gearshift lever is in "P" position. For additional information on shift and key lock systems, see SHIFT & KEY LOCK SYSTEMS under OPERATION.
When ignition is turned on, CHECK TRANS light on instrument panel should come on for about 2-3 seconds while PCM is performing a self-test of the circuit and components, then light should turn off. When ignition is on and PCM detects an electrical failure in the transmission electronic control system, the PCM will flash CHECK TRANS light and may store a diagnostic trouble code in memory.