Avalon, Camry, Sienna, Tacoma, T100 & 4Runner

Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See IDLE SPEED & MIXTURE in appropriate ON-VEHICLE ADJUSTMENTS article.

Turn ignition off. Apply parking brake and place transmission/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 located in the engine compartment. See Fig 1-76. See DATA LINK CONNECTOR NO . 1 LOCATION table.

DATA LINK CONNECTOR NO. 1 LOCATION

Application	Location
Avalon & Camry	On End Of Air Intake Chamber At Passenger's Side Of Engine
Sienna	On Engine Mount Bracket Near Passenger's Side Strut Tower
Tacoma, T100 & 4Runner	Center Of Air Intake Chamber At Driver's Side Of Engine

Start engine and note engine RPM. After engine RPM is kept at 1000 RPM for 5 seconds, ensure engine returns to idle speed. If engine speed is not as specified, test IAC valve resistance and IAC valve operation. If engine speed is as specified, remove jumper wire. Turn ignition off.
To test IAC valve resistance, ensure ignition is off. Disconnect electrical connector from IAC valve. IAC valve is located on lower area of throttle body. Using ohmmeter, checking resistance between +B terminal and each remaining terminal on IAC valve. See Fig 4-79.

Replace IAC valve if resistance is not within specification. See IAC VALVE RESISTANCE table.

IAC VALVE RESISTANCE

Application

Ohms

All Models

Cold ⁽¹⁾

17.0-24.5

Hot ⁽²⁾

21.5-28.5

⁽¹⁾	Cold is with temperature of 14-122°F (-10-50°C).

⁽²⁾	Hot is with temperature of 122-212°F (50-100°C).

To test IAC valve operation, remove IAC valve from throttle body. See appropriate REMOVE/INSTALL/OVERHAUL article. Apply battery voltage to +B terminal on IAC valve. Apply battery ground to proper terminal and ensure valve opens and closes. See Fig 7-81. Replace IAC valve if defective.
If IAC valve resistance is within specification and operates correctly, check wiring circuit between Engine Control Module (ECM) and IAC valve. See ECM LOCATION table. See appropriate wiring diagram in WIRING DIAGRAMS article.

NOTE: If all components and wiring circuit are okay, but idle problem still exists, the air assist system may be defective. For testing of air assist system, see AIR ASSIST SYSTEM under IDLE CONTROL SYSTEM .

ECM LOCATION

Model	Location
Avalon & Camry	Behind Glove Box
Sienna	Passenger's Side Of Instrument Panel, Just Below Glove Box
Tacoma	Behind Glove Box
T100	Behind Passenger's Side Kick Panel
4Runner	Behind Glove Box

Fig 1: Installing Jumper Wire Between Data Link Connector No. 1 Terminals (Avalon & Camry)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 2: Installing Jumper Wire Between Data Link Connector No. 1 Terminals (Sienna)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 3: Installing Jumper Wire Between Data Link Connector No. 1 Terminals (Tacoma, T100 & 4Runner)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 4: Testing Typical IAC Valve Resistance (Avalon & Camry)

Fig 5: Testing Typical IAC Valve Resistance (Sienna)

Fig 6: Testing Typical IAC Valve Resistance (Tacoma, T100 & 4Runner)

Fig 7: Testing IAC Valve Operation (Avalon, Camry & Sienna)

Fig 8: Testing IAC Valve Operation (Tacoma, T100 & 4Runner)