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Inspection Procedure

WARNING: This page is about a different car, the 2007 Lexus SC 430. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK ECM (ACMG VOLTAGE) 
    1. Remove ECM but do not disconnect the connector.
    2. Start the engine and push the AUTO switch.
    3. Measure the voltage of the connector when the magnet clutch is operated by the A/C switch.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      E5-11 (ACMG) - Body ground Magnet clutch: Engaged (A/C switch ON) Below 1 V
      E5-11 (ACMG) - Body ground Magnet clutch: Not engaged (A/C switch OFF) 10 to 14 V
      Fig 1: Identifying Connector Terminals Of ECM
      G05291935Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE 

    NG: Go to next step. 

  2. INSPECT FUSE (HEATER) 
    1. Remove the HEATER fuse from the driver side junction block.
    2. Measure the resistance of the fuse.

      Standard resistance: Below 1 Ω 

    NG: REPLACE FUSE 

    OK: Go to next step. 

  3. INSPECT RELAY (Marking: A/C COMP) 
    Fig 2: Inspecting Relay (Marking: ACC, A/C COMP)
    G05291936Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Remove the A/C COMP relay from the engine room No. 2 relay block.
    2. Measure the resistance of the relay.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      3 - 5 10 kΩ or higher
      3 - 5 Below 1 Ω (when battery voltage is applied to terminals 1 and 2)

    NG: REPLACE RELAY 

    OK: Go to next step. 

  4. INSPECT MAGNET CLUTCH ASSEMBLY 
    1. Disconnect the A2 clutch connector.
      Fig 3: Identifying A2 Clutch Connector
      G05291937Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Apply battery voltage to the clutch and check operation of the clutch.

      OK 

      MEASUREMENT CONNECTION SPECIFIED CONDITION CHART

      Measurement Connection Specified Condition
      Battery positive (+) → Terminal 3
      Battery negative (-) → Body ground      		 Magnet clutch is engaged

    NG: REPLACE MAGNET CLUTCH ASSEMBLY 

    OK: Go to next step. 

  5. CHECK WIRE HARNESS (ENGINE ROOM NO. 2 RELAY BLOCK - MAGNET CLUTCH, ECM AND BATTERY) 
    1. Remove the A/C COMP relay from the engine room No. 2 relay block.
    2. Disconnect the A2 clutch connector.
    3. Disconnect the E5 ECM connector.
      Fig 4: Identifying A2 Clutch Connector And E5 ECM Connector
      G05291938Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    4. Measure the voltage of the wire harness side connector.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      R/B A/C COMP relay terminal 2 - Body ground Ignition switch ON 10 to 14 V
      R/B A/C COMP relay terminal 5 - Body ground Ignition switch ON 10 to 14 V
    5. Measure the resistance of the wire harness side connector.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      R/B A/C COMP relay terminal 3 - A2-3 Below 1 Ω
      R/B A/C COMP relay terminal 1 - E5-11 Below 1 Ω

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE ECM 

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