Idle Air Control (IAC) Valve
- Listen for clicking sound at IAC valve immediately after engine is shut off.NOTE: On Turbo models, IAC valve is located on air intake chamber, near throttle body. On Non-Turbo, IAC valve is located on throttle body.
- If no clicking sound is heard, check IAC valve resistance and operation. To check IAC valve resistance, ensure ignition is off. Disconnect electrical connector from IAC valve. Note IAC valve terminals. See Fig 1 and Fig 2.
- Using ohmmeter, measure resistance between specified terminals. See IAC VALVE RESISTANCE SPECIFICATIONS table. Replace IAC valve if resistance is not within specification.IAC VALVE RESISTANCE SPECIFICATIONS
Terminals Ohms Non-Turbo B1 To All Other Terminals 18-22 B2 To All Other Terminals 18-22 Turbo B1 To All Other Terminals 18-24 B2 To All Other Terminals 18-24 - To check IAC valve operation, remove IAC valve. Note IAC valve terminal identification. See Fig 1 and Fig 2.
- Apply battery voltage to terminals B1 and B2. See Fig 1 and Fig 2. Repeatedly ground terminals in sequence and ensure IAC valve closes and opens. See IAC VALVE GROUNDING SEQUENCE table. See Fig 3 and Fig 4. 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 - If IAC valve resistance is correct and operates correctly, check wiring between Engine Control Module (ECM) and IAC valve. See appropriate wiring diagram in WIRING DIAGRAMS article.
- ECM is located below passenger's side of dash, underneath carpet on the floor.