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Home › Lexus › 2003 › LS 430 › Repair and Diagnosis › External Pages › Different car › Section 907 (Air Conditioning System - Diagnostics) › Compressor Circuit › Inspection Procedure

Inspection Procedure

WARNING: This page is about a different car, the 2005 Toyota 4Runner. However, it is still accessible from the selected car via links, so may be relevant.
  1. READ VALUE OF HAND-HELD TESTER 
    1. Connect the hand-held tester to the DLC3.
    2. Turn the ignition switch ON and push the hand-held tester main SW ON.
    3. Check the A/C magnet clutch input signal using DATA LIST.

      ECM: 

      ECM MEASUREMENT CONDITION (1 OF 2)

      Item Measurement Item / Display (Range) Normal Condition Diagnostic Note
      A/C SIG A/C signal / ON or OFF A/C switch pushed: ON A/C switch released: OFF -
    1. NG: Go to step   8 

    OK: Go to next step. 

  2. READ VALUE OF HAND-HELD TESTER 
    1. Connect the hand-held tester to DLC3.
    2. Turn the ignition switch ON and push the hand-held tester main SW ON.
    3. Check the A/C magnet clutch operation permission signal using DATA LIST.

      ECM: 

      ECM MEASUREMENT CONDITION (2 OF 2)

      Item Measurement Item / Display (Range) Normal Condition Diagnostic Note
      A/C MAG CLUTCH A/C magnet clutch / ON or OFF A/C switch ON: ON A/C switch OFF: OFF -
    1. NG: REPLACE ECM 

    OK: Go to next step. 

  3. PERFORM ACTIVE TEST BY HAND-HELD TESTER 
    1. Connect the hand-held tester to DLC3.
    2. Turn the ignition switch ON and push the hand-held tester main SW ON.
    3. Check the A/C magnet clutch operation using ACTIVE TEST.

      AIR CONDITIONER: 

      AIR CONDITIONER DIAGNOSIS DESCRIPTION

      Description Test Details / Display (Range) Diagnostic Note
      A/C MAG CLUTCH Magnet clutch relay / OFF, ON Operating sound can be heard
    1. NG: Go to step   5 

    OK: Go to next step. 

  4. CHECK HARNESS AND CONNECTOR (BETWEEN AIR CONDITIONING AMPLIFIER (ACT TERMINAL) AND ECM (ACT TERMINAL)) 
    1. Check for open and short circuit in the harness and the connector between A/C amplifier and the ECM (See ELECTRONIC CIRCUIT INSPECTION PROCEDURE ).
    1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step. 

    PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE 

  5. INSPECT COOLER RELAY ASSY 
    Fig 1: Inspecting Cooler Relay Assy
    G02576924Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Remove the cooler relay assy from the engine room J/B.
    2. Check continuity between each pair of terminals as shown in the chart.

      Standard: 

      CONTINUITY CONDITION

      Tester connection Condition Specified condition
      3 - 5 Always 10 kΩ or higher
      3 - 5 Voltage is applied between terminals 1 and 2 Below 1 Ω (Battery voltage is applied between terminals 1 and 2)
    1. NG: REPLACE COOLER RELAY ASSY 

    OK: Go to next step. 

  6. INSPECT MAGNET CLUTCH ASSY 
    1. Disconnect the connector from the compressor.
    2. Connect the battery positive (+) lead to terminal 3 and the battery negative (-) lead to terminal body ground, then check that the magnetic clutch is engaged.

      Standard: Magnetic clutch is engaged. 

      Fig 2: Inspecting Magnet Clutch Assy
      G02576925Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPLACE MAGNET CLUTCH ASSY 

    OK: Go to next step. 

  7. CHECK HARNESS AND CONNECTOR (BETWEEN AIR CONDITIONING AMPLIFIER (MGC TERMINAL) AND BODY GROUND) 
    1. Check for open and short circuit in the harness and the connector between A/C amplifier and body ground (See ELECTRONIC CIRCUIT INSPECTION PROCEDURE ).
    1. NG: REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step. 

    REPLACE AIR CONDITIONING AMPLIFIER 

  8. CHECK HARNESS AND CONNECTOR (BETWEEN AIR CONDITIONING AMPLIFIER (AC1 TERMINAL) AND ECM(AC1 TERMINAL)) 
    1. Check for open and short circuit in the harness and the connector between A/C amplifier and the ECM (See ELECTRONIC CIRCUIT INSPECTION PROCEDURE ).
    1. NG: REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step. 

  9. INSPECT AIR CONDITIONING AMPLIFIER(AC1) 
    Fig 3: Removing A/C Amplifier With Connectors Connected
    G02576926Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Remove the A/C amplifier with the connectors being connected.
    2. Start the engine and push AUTO switch.
    3. Measure voltage between terminal AC1 of the A/C amplifier and body ground when the magnetic clutch is turned ON and OFF by operating the A/C switch.

      Standard: 

      VOLTAGE CONDITION

      Switch operation Tester connection Specified condition
      ON AC1 - Body ground 1.3 to 2.6 V
      OFF AC1 - Body ground 3.7 to 4.5 V
    1. NG: REPLACE AIR CONDITIONING AMPLIFIER 

    OK: Go to next step. 

    REPLACE ECM 

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