Idle Air Control (IAC) Valve: Turbo

IAC valve is located on rear of air intake chamber, near valve cover. See Fig 1. Listen for clicking sound at IAC valve immediately after engine is shut off. If no clicking sound is heard, check IAC valve resistance and operation.

To test IAC valve resistance, ensure ignition is off. Disconnect electrical connector from IAC valve. Using ohmmeter, check resistance between specified terminals on IAC valve. See IAC VALVE RESISTANCE SPECIFICATIONS table. See Fig 1. Replace IAC valve if resistance is not within specification.

IAC VALVE RESISTANCE SPECIFICATIONS

Terminals

Ohms

Turbo

B1 To All Other Terminals

Cold ⁽¹⁾

15-25

Hot ⁽²⁾

20-30

B2 To All Other Terminals

Cold ⁽¹⁾

15-25

Hot ⁽²⁾

20-30

⁽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. See appropriate REMOVE/INSTALL/OVERHAUL article. Apply battery voltage to terminals B1 and B2. See Fig 2. Repeatedly ground terminals in sequence, and ensure IAC valve closes and opens. See IAC VALVE GROUNDING SEQUENCE table. See Fig 2. Replace IAC valve if defective.

IAC VALVE GROUNDING SEQUENCE

Application	Terminal Grounding Sequence
To Close IAC Valve	S1-S2-S3-S4-S1
To Open IAC Valve	S4-S3-S2-S1-S4

Fig 1: Locating IAC Valve & Identifying IAC Valve Terminals (Turbo)

Fig 2: Testing IAC Valve Operation (Turbo)