Electronic Control System Description

The Powertrain Control Module (PCM) and its input/output network control the following transaxle operations:
^ shift scheduling
^ line pressure (shift feel)
^ torque converter clutch scheduling
^ coast braking

The PCM receives input signals from engine-related sensors:
^ Mass Air Flow Sensor (MAF sensor)
^ Engine Coolant Temperature sensor (ECT sensor) and the Electronic Ignition (EI) system.

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). Still other inputs are provided by the following:
^ Vehicle Speed Sensor (VSS)
^ Brake Pedal Position (BPP) switch
^ Turbine Shaft Speed (TSS) sensor
^ Air Conditioning clutch (A/C)
^ Power Steering Pressure (PSP) switch
^ Transmission Range (TR) sensor (controlled by the driver placement of the transaxle range selector lever)
^ Transmission Fluid Temperature (TFT) sensor

Using all of these input signals, the powertrain control module can determine when to schedule 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 five electronic solenoids:
^ three on/off shift solenoids.
^ one pulse-width modulated Torque Converter Clutch solenoid (TCC solenoid) for Torque Converter Clutch (TCC) control.
^ an Electronic Pressure Control (EPC) solenoid for line pressure control.

The PCM also has the ability to:
^ monitor its input and output devices for the presence of faults
^ store Diagnostic Trouble Codes (DTCs) related to detected faults
^ alert the driver for some detected faults by turning on the Malfunction Indicator Lamp (MIL) in the instrument cluster
^ display information when a service technician connects diagnostic equipment

The powertrain control module receives and sends electrical signals that are used to make the transaxle more responsive to driver and vehicle needs.

The driver demands are transmitted to the powertrain control module through three components:
^ transaxle range selector lever:
- The driver's demand for a particular gear range is translated into an electrical signal for the powertrain control module by the Transmission Range (TR) sensor.
^ accelerator pedal:
- The driver's demand for torque and acceleration are sent mechanically to the throttle body on the engine. A throttle position sensor then translates this mechanical motion into an electrical signal that is monitored by the powertrain control module.
^ brake pedal:
- A Brake On/Off (BOO) switch tells the powertrain control module when the brake is applied, indicating the driver demand to disengage the torque converter.