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Idle Air Control (IAC) Valve: Corolla

  1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See IDLE SPEED & MIXTURE in ON-VEHICLE ADJUSTMENTS - 4-CYLINDER article.
  2. Turn ignition off. Apply parking brake and place transaxle in Neutral. Install Jumper Wire (SST 09843-18020) between terminals TE1 and E1 on data link connector No. 1. See Fig 13. Data link connector No. 1 is located at driver's side of engine compartment, near strut tower.
  3. Start engine and note engine RPM. After engine RPM is kept at 900-1300 RPM for 5 seconds, ensure engine returns to idle speed. If engine speed is not as specified, test IAC valve operation. If engine speed is as specified, remove jumper wire. Turn ignition off.
  4. To test IAC valve operation, remove IAC valve from throttle body. See FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. Check that valve on inside of IAC valve is half open. See Fig 14. Reinstall electrical connector on IAC valve.
  5. Disconnect electrical connector from Engine Coolant Temperature (ECT) sensor. ECT sensor is located on flywheel end of cylinder head below ignition coil and contains a Dark Gray 2-pin electrical connector with White and Brown wires.
  6. Turn ignition on. Check that valve on inside of IAC valve moves. Repeatedly disconnect and reconnect electrical connector for IAC valve several times while checking that valve on inside of IAC valve opens and closes. See Fig 14.
  7. Turn ignition off. Reinstall electrical connector on ECT sensor. Remove jumper wire.
  8. If IAC valve operates, wiring circuit, Engine Control Module (ECM) and IAC valve are okay. If IAC valve does not operate, check wiring circuit between ECM and IAC valve. See ECM LOCATION  table. See appropriate wiring diagram in WIRING DIAGRAMS article. If wiring circuit and ECM are okay, replace IAC valve.
ECM LOCATION

Model (1) Location
Camry & Camry Solara Behind Glove Box
Celica Below Passenger's Side Of Instrument Panel, Underneath Carpet Near Center Console
Corolla Behind Stereo On Instrument Panel, Just In Front Of Center Console
RAV4 Behind Instrument Panel, Near Front Of Center Console
Tacoma & 4Runner Behind Glove Box
(1) For illustration of ECM location, see THEORY & OPERATION article.
Fig 1: Installing Jumper Wire Between Data Link Connector No. 1 Terminals (Camry)
G99B08030Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 2: Installing Jumper Wire Between Data Link Connector No. 1 Terminals (Camry Solara)
G99D08031Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 3: Installing Jumper Wire Between Data Link Connector No. 1 Terminals (Celica)
G95H30889Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 4: Installing Jumper Wire Between Data Link Connector No. 1 Terminals (RAV4)
G96F09526Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 5: Installing Jumper Wire Between Data Link Connector No. 1 Terminals (Tacoma & 4Runner)
G95F30895Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 6: Testing IAC Valve Resistance (Camry & Camry Solara)
G97F06373Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 7: Testing IAC Valve Resistance (Celica)
G97A06375Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 8: Testing IAC Valve Resistance (RAV4)
G98G11847Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 9: Testing IAC Valve Resistance (Tacoma & 4Runner)
G95B33705Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 10: Testing IAC Valve Operation (Camry, Camry Solara & Celica)
G97H06374Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 11: Testing IAC Valve Operation (RAV4)
G95J33711Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 12: Testing IAC Valve Operation (Tacoma & 4Runner)
G95B34430Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 13: Installing Jumper Wire Between Data Link Connector No. 1 Terminals (Corolla)
G98E11225Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 14: Testing IAC Valve Operation (Corolla)
G98F11846Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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