1994 Toyota Land CruiserFACTORY OEM SERVICE PROCEDURE

Idle Control System

  1. Listen for clicking sound at IAC valve immediately after engine is shut off.
    NOTE: On Land Cruiser, IAC valve is located on throttle body.
  2. 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.
  3. 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
    B1 To S1 Or S3 10-30
    B2 To S2 Or S4 10-30
  4. To check IAC valve operation, remove IAC valve. Note IAC valve terminal identification. See Fig 1.
  5. Apply battery voltage to terminals B1 and B2. See Fig 1. Repeatedly ground terminals in sequence and ensure IAC valve closes and opens. See IAC VALVE GROUNDING SEQUENCE  table. See Fig 2 and Fig 3. 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
  6. 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.
  7. ECM is located above glove box.
Fig 1: Identifying IAC Valve Terminals
G93E80139Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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