Gear Shift Operation; Lock–Up Operation; Stop Light Sw Circuit; Overdrive Circuit - Toyota 1994 CAMRY Repair Manual

SYSTEM OUTLINE
PREVIOUS AUTOMATIC TRANSMISSIONS HAVE SELECTED EACH GEAR SHIFT USING MECHANICALLY CONTROLLED THROTTLE
HYDRAULIC PRESSURE, GOVERNOR HYDRAULIC PRESSURE AND LOCK–UP HYDRAULIC PRESSURE. THE ELECTRONIC
CONTROLLED TRANSMISSION, HOWEVER, ELECTRICALLY CONTROLS THE LINE PRESSURE AND LOCK–UP PRESSURE ETC.,
THROUGH THE SOLENOID VALVE. ENGINE CONTROL MODULE (ENGINE AND ELECTRONIC CONTROLLED TRANSMISSION ECU)
CONTROL OF THE SOLENOID VALVE BASED ON THE INPUT SIGNALS FROM EACH SENSOR MAKES SMOOTH DRIVING POSSIBLE BY
SHIFT SELECTION FOR EACH GEAR WHICH IS MOST APPROPRIATE TO THE DRIVING CONDITIONS AT THAT TIME.

1. GEAR SHIFT OPERATION

DURING DRIVING, THE ENGINE CONTROL MODULE (ECU) SELECTS THE SHIFT FOR EACH GEAR WHICH IS MOST APPROPRIATE TO
THE DRIVING CONDITIONS, BASED ON INPUT SIGNALS FROM THE ENGINE COOLANT TEMP. SENSOR (EFI WATER TEMP. SENSOR)
TO TERMINAL THW OF THE ENGINE CONTROL MODULE (ECU), AND ALSO THE INPUT SIGNALS TO TERMINAL NC2+ OF THE ENGINE
CONTROL MODULE (ECU) FROM THE VEHICLE SPEED SENSOR (SPEED SENSOR) DEVOTED TO THE ELECTRONIC CONTROLLED
TRANSMISSION. CURRENT IS THEN OUTPUT TO THE ELECTRONIC CONTROLLED TRANSMISSION SOLENOIDS. WHEN SHIFTING TO
1ST SPEED, CURRENT FLOWS FROM TERMINAL S1 OF THE ENGINE CONTROL MODULE (ECU)
CONTROLLED TRANSMISSION SOLENOIDS
FOR 2ND SPEED, CURRENT FLOWS FROM TERMINAL S1 OF THE ENGINE CONTROL MODULE (ECU)
ELECTRONIC CONTROLLED TRANSMISSION SOLENOIDS
MODULE (ECU) TERMINAL 1 OF THE ELECTRONIC CONTROLLED TRANSMISSION SOLENOIDS
SOLENOIDS NO. 1 AND NO. 2 CAUSES THE SHIFT.
FOR 3RD SPEED, THERE IS NO CONTINUITY TO NO. 1 SOLENOID, ONLY TO NO. 2, CAUSING THE SHIFT.
SHIFTING INTO 4TH SPEED (OVERDRIVE) TAKES PLACE WHEN THERE IS NO CONTINUITY TO EITHER NO. 1 OR NO. 2 SOLENOID.
2. LOCK–UP OPERATION
WHEN THE ENGINE CONTROL MODULE (ECU) JUDGES FROM EACH SIGNAL THAT LOCK–UP OPERATION CONDITIONS HAVE BEEN
MET, CURRENT FLOWS FROM TERMINAL SL OF THE ENGINE CONTROL MODULE (ECU)
CONTROLLED TRANSMISSION SOLENOID
LOCK–UP OPERATION.

3. STOP LIGHT SW CIRCUIT

IF THE BRAKE PEDAL IS DEPRESSED (STOP LIGHT SW ON) WHEN DRIVING IN LOCK–UP CONDITION, A SIGNAL IS INPUT TO
TERMINAL STP OF THE ENGINE CONTROL MODULE (ECU), THE ENGINE CONTROL MODULE (ECU) OPERATES AND CONTINUITY TO
THE LOCK–UP SOLENOID IS CUT.

4. OVERDRIVE CIRCUIT

* O/D MAIN SW ON
WHEN THE O/D MAIN SW IS TURNED ON (O/D OFF INDICATOR LIGHT TURNS OFF), A SIGNAL IS INPUT TO TERMINAL OD2 OF THE
ENGINE CONTROL MODULE (ECU) AND ENGINE CONTROL MODULE (ECU) OPERATION CAUSES GEAR SHIFT WHEN THE
CONDITIONS FOR OVERDRIVE ARE MET.
* O/D MAIN SW OFF
WHEN THE O/D MAIN SW IS TURNED TO OFF, THE CURRENT FLOWING THROUGH THE O/D OFF INDICATOR LIGHT FLOWS
THROUGH THE O/D MAIN SW TO GROUND. CAUSING THE INDICATOR LIGHT TO LIGHT UP. AT THE SAME TIME, A SIGNAL IS INPUT
TO TERMINAL OD2 OF THE ENGINE CONTROL MODULE (ECU) AND ENGINE CONTROL MODULE (ECU) OPERATION PREVENTS
SHIFT INTO OVERDIRVE.
5. ELECTRONIC CONTROLLED TRANSMISSION PATTERN SELECT SW CIRCUIT
IF THE ELECTRONIC CONTROLLED TRANSMISSION PATTERN SELECT SW IS CHANGED FROM NORMAL TO POWER, THE CURRENT
FLOWING THROUGH THE POWER INDICATOR FLOWS TO GROUND, CURRENT FLOWS TO TERMINAL P OF THE ENGINE CONTROL
MODULE (ECU), THE ENGINE CONTROL MODULE (ECU) OPERATES, AND SHIFT UP AND SHIFT DOWN OCCUR AT HIGHER VEHICLE
SPEEDS THAN WHEN THE SW IS IN NORMAL POSITION.
GROUND, AND CONTINUITY TO THE NO. 1 SOLENOID CAUSES THE SHIFT.
GROUND, AND FROM TERMINAL S2 OF THE ENGINE CONTROL
GROUND, CAUSING CONTINUITY TO THE LOCK–UP SOLENOID AND CAUSING
TERMINAL 3 OF THE ELECTRONIC
TERMINAL 3 OF THE
GROUND, AND CONTINUITY TO
TERMINAL 2 OF THE ELECTRONIC
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