TSRM/MK4 Supra/Repair Manual
Repair ManualWiring Diagrams
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WD/Wiring Diagrams80 / 277
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SYSTEM OUTLINE — MK4 Supra Wiring Diagrams, page 80
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ENGINE CONTROL (FOR 2JZ–GE) SYSTEM OUTLINE THE ENGINE CONTROL SYSTEM UTILIZES A MICROCOMPUTER AND MAINTAINS OVERALL CONTROL OF THE ENGINE, TRANSMISSION ETC. AN OUTLINE OF THE ENGINE CONTROL IS GIVEN HERE. 1. INPUT SIGNALS (1) ENGINE COOLANT TEMP. (WATER TEMP.) SIGNAL CIRCUIT THE ENGINE COOLANT TEMP. SENSOR (EFI WATER TEMP. SENSOR) DETECTS THE ENGINE COOLANT TEMP. (WATER TEMP.) AND HAS A BUILT–IN THERMISTOR WITH A RESISTANCE, WHICH VARIES ACCORDING TO THE ENGINE COOLANT TEMP. (WATER TEMP.) WHICH IS INPUT INTO TERMINAL THW OF THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) AS A CONTROL SIGNAL. (2) INTAKE AIR TEMP. SIGNAL CIRCUIT THE INTAKE AIR TEMP. SENSOR IS INSTALLED IN THE VOLUME AIR FLOW (AIR FLOW METER) AND DETECTS THE INTAKE AIR TEMP. WHICH IS INPUT AS A CONTROL SIGNAL TO TERMINAL THA OF THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU). (3) OXYGEN DENSITY SIGNAL CIRCUIT (EXCEPT CALIFORNIA) THE OXYGEN DENSITY IN THE EXHAUST EMISSION IS DETECTED BY THE OXYGEN SENSOR FRONT AND REAR SIDE AND INPUT AS A CONTROL SIGNAL TO TERMINALS OX1, OX2 OF THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU). (FOR CALIFORNIA) THE OXYGEN DENSITY IN THE EXHAUST EMISSION IS DETECTED BY THE HEATED OXYGEN SENSOR FRONT AND REAR SIDE AND INPUT AS A CONTROL SIGNAL TO TERMINALS OX1, OX2, OX3 OF THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU). (4) RPM SIGNAL CIRCUIT CRANKSHAFT POSITION IS DETECTED BY THE PICK–UP COIL INSTALLED INSIDE THE DISTRIBUTOR. CRANKSHAFT POSITION IS INPUT AS A CONTROL SIGNAL TO TERMINALS G1 AND G2 OF THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU), AND ENGINE SPEED IS INPUT TO TERMINAL NE. (5) THROTTLE POSITION SIGNAL CIRCUIT THE THROTTLE POSITION SENSOR DETECTS THE THROTTLE VALVE OPENING ANGLE AS A CONTROL SIGNAL, WHICH IS INPUT INTO TERMINAL VTA1 OF THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU). WHEN THE VALVE IS COMPLETELY CLOSED, THE CONTROL SIGNAL IS INPUT INTO TERMINAL IDL1. (6) VEHICLE SPEED CIRCUIT THE VEHICLE SPEED IS DETECTED BY VEHICLE SPEED SENSOR (SPEED SENSOR) NO.1 INSTALLED IN THE TRANSMISSION AND THE SIGNAL IS INPUT TO TERMINAL SP1 OF THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) VIA THE COMBINATION METER. (7) NEUTRAL POSITION SIGNAL CIRCUIT THE PARK/NEUTRAL POSITION SW (NEUTRAL START SW) DETECTS WHETHER THE SHIFT POSITION IS IN "N" OR "P" OR NOT, AND THE SIGNAL IS INPUT INTO TERMINAL NSW OF THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU). (8) A/C SW SIGNAL CIRCUIT THE OPERATING VOLTAGE OF THE A/C MAGNETIC CLUTCH IS DETECTED AND THE SIGNAL IS INPUT INTO TERMINAL ACMG OF ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) AS A CONTROL SIGNAL. (9) BATTERY SIGNAL CIRCUIT VOLTAGE IS CONSTANTLY APPLIED TO TERMINAL BATT OF THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU). WITH THE IGNITION SW TURNED ON, THE VOLTAGE FOR ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) START–UP POWER SUPPLY IS APPLIED TO TERMINALS +B OF THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) VIA EFI MAIN RELAY. THE CURRENT FLOWING THROUGH THE IGN FUSE FLOWS TO TERMINAL IGSW OF THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU). (10) INTAKE AIR VOLUME SIGNAL CIRCUIT INTAKE AIR VOLUME IS DETECTED BY THE VOLUME AIR FLOW (AIR FLOW METER) AND THE SIGNAL IS INPUT TO TERMINAL KS OF THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) AS A CONTROL SIGNAL. (11) STOP LIGHT SW SIGNAL CIRCUIT THE STOP LIGHT SW IS USED TO DETECT WHETHER THE VEHICLE IS BRAKING OR NOT AND THE SIGNAL IS INPUT INTO TERMINAL STP OF THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) AS A CONTROL SIGNAL. (12) STARTER SIGNAL CIRCUIT TO CONFIRM WHETHER THE ENGINE IS CRANKING, THE VOLTAGE IS APPLIED TO THE STARTER MOTOR DURING CRANKING IS DETECTED AND THE SIGNAL IS INPUT INTO TERMINAL STA OF THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) AS A CONTROL SIGNAL. 82