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AT-28 OVERALL SYSTEM TCM FUNCTION The function of the TCM is to: ● Receive input signals sent from various switches and sensors. ● Determine required line pressure, shifting point, lock-up operation, and engine brake operation. ● Send required output signals to the respective solenoid valves. INPUT/OUTPUT SIGNAL OF TCM Control Mechanism ECS0096R LINE PRESSURE CONTROL TCM has various line pressure control characteristics to match the driving conditions. Normal Control The line pressure to throttle opening characteristics is set for suitable Sensors, switches and solenoid valves Function Input PNP switch Detects select lever position and sends a signal to TCM. Throttle position sensor (accelerator Detects throttle valve position and sends a signal to TCM. Engine speed signal From ECM. A/T fluid temperature sensor Detects transmission fluid temperature and sends a signal to TCM. Revolution sensor Detects output shaft rpm and sends a signal to TCM. Vehicle speed sensor Used as an auxiliary vehicle speed sensor. Sends a signal when revolution Overdrive control switch Sends a signal, which prohibits a shift to “D 4 ” (overdrive) position, to the TCM. Stop lamp switch Releases lock-up system when depressing pedal in lock-up condition. Output Shift solenoid valve A/B Selects shifting point suited to driving conditions in relation to a signal sent Line pressure solenoid valve Regulates (or decreases) line pressure suited to driving conditions in relation Torque converter clutch solenoid Regulates (or decreases) lock-up pressure suited to driving conditions in rela- Overrun clutch solenoid valve Controls an “engine brake” effect suited to driving conditions in relation to a O/D OFF indicator lamp Shows TCM faults when A/T control components malfunction. SAT003J |