{"model":"mk4","model_name":"MK4 Supra","vehicle":"Toyota Supra A80 (1993–2002, 2JZ-GE / 2JZ-GTE)","document":"Repair Manual","section":"TGTE","section_name":"Troubleshooting 2JZ-GTE","page":100,"pages_in_section":113,"title":"IAC Valve Circuit","section_header":"Engine — 2JZ–GTE Engine Troubleshooting","ocr_text":"EG–586\nENGINE – 2JZ–GTE ENGINE TROUBLESHOOTING\n\nIAC Valve Circuit\n\nCIRCUIT DESCRIPTION\n\nThe IAC valve is situated on the intake air chamber Intake air bypassing the throttle valve is directed to the IAC valve through a passage.\nA step motor is built into the IAC valve. It consists of 4 coils, a magnetic rotor, valve shaft and a valve.\nWhen the current flows to the coils due to signals from the ECM, the rotor turns and moves the valve shaft forward or backward, changing the clearance between the valve and the valve seat.\nIn this way the intake air volume bypassing the throttle valve is regulated, controlling the engine speed.\nThere are 125 possible positions to which the valve can be opened.\n\nThrottle Body\nIntake\nAir\nChamber\nFrom\nAir\nFlow\nMeter\nValve\nThrottle\nValve\nCoils\nTo\nCylinder Head\nRotor\nValve Shaft\n\nFI6973\n\nReference    INSPECTION USING OSCILLOSCOPE\n\nA/C Switch OFF → ON\n(IAC Valve open)\nISC1\nISC2\nISC3\nISC4\n20 V/Div.\n10 msec./Division\n\n• With the engine idling measure wave forms between terminals ISC1, ISC2, ISC3, ISC4 and E01 of engine control module when A/C switch ON or OFF.\nHINT:\nThe correct waveforms are as shown.\n\nA/C Switch ON → OFF\n(IAC Valve close)\nISC1\nISC2\nISC3\nISC4\n20 V/Div.\n10 msec./Division\n\nFI6536\nFI6537","image":"https://tsrm.sasquatchvc.com/images/mk4/TGTE/TGTE_100.png","url":"https://tsrm.sasquatchvc.com/mk4/tsrm/TGTE/100","prev":{"page":99,"url":"https://tsrm.sasquatchvc.com/mk4/tsrm/TGTE/99","api":"https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/99"},"next":{"page":101,"url":"https://tsrm.sasquatchvc.com/mk4/tsrm/TGTE/101","api":"https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/101"},"section_url":"https://tsrm.sasquatchvc.com/mk4/tsrm/TGTE","section_api_pages":["https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/1","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/2","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/3","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/4","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/5","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/6","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/7","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/8","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/9","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/10","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/11","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/12","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/13","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/14","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/15","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/16","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/17","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/18","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/19","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/20","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/21","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/22","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/23","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/24","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/25","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/26","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/27","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/28","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/29","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/30","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/31","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/32","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/33","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/34","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/35","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/36","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/37","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/38","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/39","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/40","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/41","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/42","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/43","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/44","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/45","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/46","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/47","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/48","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/49","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/50","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/51","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/52","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/53","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/54","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/55","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/56","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/57","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/58","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/59","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/60","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/61","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/62","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/63","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/64","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/65","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/66","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/67","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/68","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/69","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/70","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/71","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/72","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/73","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/74","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/75","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/76","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/77","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/78","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/79","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/80","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/81","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/82","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/83","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/84","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/85","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/86","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/87","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/88","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/89","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/90","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/91","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/92","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/93","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/94","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/95","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/96","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/97","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/98","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/99","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/100","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/101","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/102","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/103","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/104","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/105","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/106","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/107","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/108","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/109","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/110","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/111","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/112","https://tsrm.sasquatchvc.com/api/pages/mk4/tsrm/TGTE/113"],"note":"OCR transcript of a scanned Toyota factory manual page; verify critical values (torque specs, part numbers) against the image."}