Overdrive Range, Fourth Gear - TCC Applied

FOURTH, THIRD or SECOND GEAR (Torque Converter Clutch Applied) The torque converter clutch applies during second, third or fourth gear operation after the Powertrain Control Module (PCM) receives the appropriate input signals to energize the torque converter clutch control solenoid (TCC PWM). To apply the torque converter clutch, the following changes take place in the electrical and hydraulic systems:

TCC CONTROL SOLENOID
When conditions are appropriate, the PCM energizes the TCC control solenoid to initiate the TCC apply. The Solenoid is Pulse Width Modulated (PWM) to provide a smooth TCC apply. When energized, the solenoid modulates 2nd fluid into the TCC PWM signal fluid circuit.

TCC REGULATOR VALVE
TCC signal fluid pressure modulates the valve against spring force and TCC regulator apply fluid pressure. This action directs line pressure into the TCC regulated apply fluid circuit in relation to vehicle operating conditions.

TCC CONTROL VALVE
Modulated TCC signal fluid pressure moves the valve against spring force in relation to vehicle operating conditions. This action regulates TCC regulated apply fluid into the apply fluid circuit. At the same time, the release fluid circuit is opened to an orificed exhaust. In this position the valve directs TCC feed limit fluid to feed the cooler fluid circuit.

TORQUE CONVERTER CLUTCH
Apply fluid is routed to the torque converter at the same time release fluid exhausts from the converter. Apply fluid pressure applies the TCC.

TRANSMISSION FLUID PRESSURE (TFP) MANUAL VALVE POSITION SWITCH
Release fluid also exhausts from the TFP and the TFP signals the PCM that the TCC is engaged.

COOLER CHECK VALVE (28)
Allows cooler fluid to pass through the cooler and provide lubrication for the transaxle. It also prevents converter drainback when the engine is off.

No. 1 BALL CHECK VALVE (372)
Located in the case cover (400), blocks release fluid while sending apply fluid to the torque converter clutch blow off valve (417-20).

CONVERTER CLUTCH BLOW-OFF VALVE
Limits maximum TCC apply pressure to prevent torque converter damage.