Idle Air Control (IAC) Valve: Avalon
- Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See IDLE SPEED & MIXTURE in ON-VEHICLE ADJUSTMENTS - V6 & V8 article.
- Turn ignition off. Apply parking brake and place transaxle in Neutral. Ensure A/C is off. Install Jumper Wire (SST 09843-18020) between terminals TE1 and E1 on data link connector No. 1. Data link connector No. 1 is located in the engine compartment on end of air intake chamber at passenger's side of engine. See Figure.
- Start engine and note engine RPM. Engine should increase to 1000 RPM for 5 seconds and then return to idle speed. If engine speed is not as specified, test IAC valve operation. Go to next step. If engine speed is as specified, remove jumper wire. Turn ignition off.
- To test IAC valve operation, remove IAC valve from throttle body. See THROTTLE BODY under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. Check that valve on inside of IAC valve is half open. See Figure. Reinstall electrical connector on IAC valve.
- Turn ignition on. Check that valve on inside of IAC valve moves to fully closed position, fully open position and then returns to half open position.
- If IAC valve operates properly, it may be necessary to check wiring circuit between Engine Control Module (ECM) and IAC valve for intermittent problem. ECM is located behind glove box. If wiring circuit is okay, but idle problem still exists, the air assist system may be defective. For testing of air assist system, see AIR ASSIST SYSTEM . If IAC valve does not operate properly, check wiring circuit between Engine Control Module (ECM) and IAC valve. ECM is located behind glove box. If wiring circuit is okay, replace IAC valve. See ECM LOCATION table. See appropriate wiring diagram in WIRING DIAGRAMS article.