ELECTRONIC CONTROL SYSTEM STRUCTURE [5R55S]

• Many input sensors provide information to the TCM. The TCM then controls the actuators which determine transmission operation.

• An electromagnetic clutch is energized when the clutch cycling pressure switch closes.

• The switch is located on the suction accumulator/drier.

• The closing of the switch completes the circuit to the clutch and draws it into engagement with the compressor driveshaft.

• When the A/C is engaged, operating pressures are adjusted to compensate for additional load on the engine.

• The brake switch tells the PCM when the brakes are applied.

• The PCM sends this message to TCM via CAN bus.

• The torque converter clutch disengages when the brakes are applied.

• The brake switch closes when the brakes are applied and opens when they are released.

• The ECT sensor detects temperature of engine coolant and supplies the information to the PCM.

• The PCM sends this message to TCM via CAN bus.

• The ECT sensor is used to control torque converter clutch (TCC) operation.

• The CKP sensor detects pulse wheel rotational signals as crank angle signals.

• The PCM sends this message to TCM via CAN bus.

• The PCM uses engine speed signal in the transmission strategy, wide-open throttle (WOT) shift control, torque converter clutch control and operating pressures.

• The MAF sensor measures the mass of air flowing into the engine.

• The PCM sends this message to TCM via CAN bus.

• The MAF sensor output signal is used by the PCM to calculate injector pulse width.

• For transmission strategies, the MAF sensor is used to regulate electronic pressure control, shift and torque converter clutch scheduling.

• The O/D OFF switch is a momentary contact switch that allows the driver to cancel operation of 5GR.

• The O/D OFF switch is located on the left side of the selector lever.

• When the driver initially presses the O/D OFF switch a signal is sent to the TCM.

• The TCM uses the shift solenoids to disengage/disable 5GR operation and activate the coast clutch. At the same time, the TCM illuminates the O/D OFF Indicator Light to notify the driver that 5GR is canceled.

• When the O/D OFF switch is pressed again, 5GR operation is enabled, the coast clutch is released and the O/D OFF indicator light is turned off.

• Whenever the ignition is cycled (vehicle shut off, then started again), the O/D OFF switch is turned off and 5GR will be enabled, even if the O/D OFF switch had been on when the ignition was shut off.

• The O/D OFF indicator light is located in the instrument panel and is labeled O/D OFF. It is illuminated in conjunction with the O/D OFF switch.

• The APP sensor is mounted on the accelerator pedal. The APP sensor detects the position of the accelerator pedal and inputs this information as a voltage to the PCM.

• The PCM sends this message to TCM via CAN bus.

• The TCM uses the APP sensor information to aid in determining shift scheduling, presser control and torque converter control.

• The digital TR sensor is located on the outside of the transmission at the manual lever.

• The digital TR sensor completes the start circuit in PARK, NEUTRAL and the back-up lamp circuit in REVERSE.

• The digital TR sensor also opens and closes a set of 4 switches that are monitored by the TCM to determine the position of the manual lever (P, R, N, D, 3, 2, 1).

• The TSS sensor is a magnetic pickup that sends the TCM torque converter turbine speed information.

• The TSS sensor is mounted externally on the case.

• The TCM uses TSS information to help determine appropriate operating pressures and TCC operation.

• The OSS sensor is a magnetic pickup, located at the park gear trigger wheel assembly, that sends a signal to the TCM to indicate transmission output shaft speed.

• The OSS sensor is mounted externally on the case.

• The OSS is used for torque converter clutch control, shift scheduling and to determine pressure control.

• The ISS sensor is a magnetic pickup that sends planetary sun gear speed information to the TCM.

• It is mounted externally on the center of the case.

• The TCM uses the intermediate shaft speed sensor information to aid in determining pressure requirements.

• The pressure control solenoids are a variable-force style (VFS) solenoid. The VFS-type solenoid is an electro-hydraulic actuator combining a solenoid and a regulating valve.

• The line pressure tap is used to verify output pressure from pressure control solenoid A or B by turning either one off while verifying the output from the other solenoid.

• The second pressure tap is used to verify the output from the pressure control solenoid C.

• There are 3 pressure control solenoids located in the solenoid body assembly used to control line pressure, band and clutch application pressure within the transmission.

• The TCM varies the current to the pressure control solenoid.

• The TCM has an adaptive learn strategy to electronically control the transmission which will automatically adjust the shift feel. When the battery has been disconnected or a new battery installed, certain transmission operating parameters may be lost. The TCM must relearn these parameters.

• During this learning process you may experience slightly firm shifts, delayed or early shifts. This operation is considered normal and will not affect the function of the transmission. Normal operation will return once these parameters are stored by the TCM.

• The TCC control solenoid is a pulse width modulating type solenoid which is used to control the apply and release of the TCC.

• Four ON/OFF shift solenoids allow the TCM to control shift scheduling.

• Coast braking and manual gears are also controlled by the shift solenoids.

• The TFT sensor is a thermistor-type sensor that varies a reference voltage signal. The resistance in the TFT varies with temperature.

• The TCM monitors the voltage signal across the TFT and uses this information to determine the transmission fluid temperature.

• The TFT is located on the solenoid body.

• The TCM uses the TFT signal to help determine shift scheduling, torque converter clutch operation and pressure control requirements.

• It sends a voltage signal to the TCM. The voltage signal varies with transmission fluid temperature. The TCM uses this signal to determine whether a cold start shift schedule is necessary. The shift schedule is compensated when the transmission fluid temperature is cold. The TCM also inhibits TCC operation at low transmission fluid temperatures and uses it to determine PC solenoid operations.