Toyota 1993 MR2, Wiring Diagrams

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156
ECT AND A/T INDICATOR
THIS SYSTEM ELECTRONICALLY CONTROLS THE GEAR SHIFT TIMING, LOCK–UP TIMING, THE CLUTCH AND BRAKE HYDRAULIC
PRESSURE, AND THE ENGINE TORQUE DURING SHIFTING, TO ACHIVE OPTIMUM SHIFT FEELING.
IN ACCORDANCE TO THE VEHICLE DRIVING CONDITIONS AND ENGINE OPERATING CONDITIONS AS DETECTED BY VARIOUS
SENSORS.
1. GEAR SHIFT OPERATION
DURING DRIVING, THE PCME (ENGINE AND ECT ECU) SELECTS THE SHIFT FOR EACH GEAR WHICH IS MOST APPROPRIATE TO
THE DRIVING CONDITIONS, BASED ON INPUT SIGNALS FROM THE ECTS (EFI WATER TEMP. SENSOR) TO TERMINAL THW OF THE
PCME (ENGINE AND ECT ECU), AND ALSO THE INPUT SIGNALS TO TERMINAL SP2 OF THE PCME (ENGINE AND ECT ECU) FROM
THE SPEED SENSOR DEVOTED TO THE ECT. CURRENT IS THEN OUTPUT TO THE ECT SOLENOIDS. WHEN SHIFTING TO 1ST SPEED,
CURRENT FLOWS FROM TERMINAL S1 OF THE PCME (ENGINE AND ECT ECU)
→
TERMINAL 3 OF THE ECT SOLENOIDS
→
GROUND,
AND CONTINUITY FLOW TO NO.1 SOLENOID CAUSES THE SHIFT.
FOR 2ND SPEED, CURRENT FLOWS FROM TERMINAL S1 OF THE PCME (ENGINE AND ECT ECU)
→
TERMINAL 3 OF THE ECT
SOLENOIDS
→
GROUND, AND FROM TERMINAL S2 OF THE PCME (ENGINE AND ECT ECU)
→
TERMINAL 1 OF THE ECT SOLENOIDS
→
GROUND, AND CONTINUITY TO SOLENOIDS NO. 1 AND NO. 2 CAUSE THE SHIFT.
FOR 3RD SPEED, THERE IS NO CONTINUITY TO NO. 1 SOLENOID, ONLY TO NO. 2, CAUSING THE SHIFT.
SHIFTING INTO 4TH SPEED (OVER DRIVE) TAKES PLACE WHEN THERE IS NO CONTINUITY TO EITHER NO. 1 OR NO. 2 SOLENOID.
2. LOCK–UP OPERATION
WHEN THE PCME (ENGINE AND ECT ECU) JUDGES FROM EACH SIGNAL THAT LOCK–UP OPERATION CONDITIONS HAVE BEEN MET,
CURRENT FLOWS FROM TERMINAL SL OF THE PCME (ENGINE AND ECT ECU)
→
TERMINAL 2 OF THE ETC SOLENOIDS
→
GROUND, CAUSING A CONTINUITY TO THE TCC (LOCK–UP SOLENOID) AND CAUSING 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 B/K OF THE PCME (ENGINE AND ECT ECU), THE PCME (ENGINE AND ECT ECU) OPERATES AND CONTINUITY TO THE
TCC (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
PCME (ENGINE AND ECT ECU) AND PCME (ENGINE AND ECT ECU) OPERATION CAUSES GEAR SHIFT WHEN THE CONDITIONS
FOR OVERDRIVE ARE MET.
* O/D MAIN SW OFF
WHEN THE OVERDRIVE SW IS TURNED 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 PCME (ENGINE AND ECT ECU) AND PCME (ENGINE AND ECT ECU) OPERATION PREVENTS SHIFT
INTO OVERDRIVE.
E 6(A), E 7(C), E 8(B)
PCME (ENGINE AND ECT ECU)
(A) 4– (B)14
: 10–14 VOLTS (BRAKE PEDAL IS DEPRESSED)
1 VOLTS OR LESS (BRAKE PEDAL IS RELEASED)
(C) 4– (C) 9
: 0.3–0.8 VOLTS (IGNITION SW ON AND COOLANT TEMP. 80
°
C (176
°
F))
(C)12– (C) 9
: 8–14 VOLTS (IGNITION SW ON AND THROTTLE VALVE FULLY OPEN)
(C)11– (C) 9
: 0.8–1.2 VOLTS (IGNITION SW ON AND THROTTLE VALVE FULLY CLOSED)
3.2–4.2 VOLTS (IGNITION SW ON AND THROTTLE VALVE FULLY OPEN)
(C) 1– (C) 9
: 4.5–5.5 VOLTS (IGNITION SW ON)
(A)20– (B)14
: 10–14 VOLTS (IGNITION SW ON)
(A) 7– (B)14
: 10–14 VOLTS (IGNITION SW ON AND O/D MAIN SW TURNED ON)
1 VOLTS OR LESS (IGNITION SW ON AND O/D MAIN SW TURNED OFF)
(A) 9– (B)14
: 1 VOLTS OR LESS (IGNITION SW ON, CRUISE CONTROL SW OFF AND STARTING STILL)
0
10–14 VOLTS REPEAT (IGNITION SW ON, CRUISE CONTROL SW OFF AND VEHICLE MOVING)
(B)16– (B)14
: 1 VOLTS OR LESS (IGNITION SW ON AND STARTING STILL)
0
4.5–5.5 VOLTS REPEAT (IGNITION SW ON AND VEHICLE MOVING)
(A)22– (B)14
: 6.0–14 VOLTS (IGNITION SW ON AND PNS (NEUTRAL START SW) P OR N POSITION)
0–2.0 VOLTS (IGNITION SW ON AND EX. PNS (NEUTRAL START SW) P OR N POSITION)
(B) 6– (B)14
: 10–14 VOLTS (IGNITION SW ON AND PNS (NEUTRAL START SW) 2 POSITION)
1 VOLTS OR LESS (IGNITION SW ON AND EX. PNS (NEUTRAL START SW) 2 POSITION)
(B)19– (B)14
: 10–14 VOLTS (IGNITION SW ON AND PNS (NEUTRAL START SW) L POSITION)
1 VOLTS OR LESS (IGNITION SW ON AND EX. PNS (NEUTRAL START SW) L POSITION)
(A)12– (A)13– (B)14
:10–14 VOLTS (IGNITION SW ON)
(A) 1– (B)14
: 10–14 VOLTS (ALL CONDITIONS)
SYSTEM OUTLINE
SERVICE HINTS