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Home >> Lexus >> 2007 >> LS 460L >> Repair and Diagnosis >> Suspension >> Suspension Control Systems >> Air Suspension System >> DTC C1752 Height Control Compressor Motor Circuit Malfunction >> Inspection Procedure

Inspection Procedure

NOTE:
  • Before performing troubleshooting, inspect the connectors of related circuits.
  • Before replacing the suspension control ECU, perform all of the following again: 1) symptom simulation (see ELECTRONIC CIRCUIT INSPECTION PROCEDURE ); 2) DTC inspection; and 3) Intelligent tester or Techstream inspection (Data List or Active Test). If no malfunctions are found in other areas, replace the suspension control ECU.
  • If the suspension control ECU or height control sensor is replaced, the vehicle height offset calibration must be performed (see INITIALIZATION  ).
  1. INSPECT SUSPENSION CONTROL RELAY (AIRSUS) 
    1. Turn the engine switch off.
    2. Remove the suspension control relay from the engine room No. 1 relay block.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      SUSPENSION CONTROL RELAY (AIRSUS)

      Tester Connection Condition Specified Condition
      3-5 When battery voltage is not applied to terminal 1 and 2 10 kΩ or higher
      When battery voltage is applied to terminal 1 and 2 Below 1 Ω
      Fig 1: Inspecting Suspension Control Relay (Airsus)
      G04944147Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE SUSPENSION CONTROL RELAY 

    OK: GO TO NEXT STEP 

  2. CHECK HARNESS AND CONNECTOR (ECU - COMPRESSOR, COMPRESSOR - BATTERY AND BODY GROUND) 
    1. Remove the suspension control relay from the engine room No. 1 relay block.
    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      ECU - COMPRESSOR, COMPRESSOR - BATTERY AND BODY GROUND VOLTAGE

      Tester Connection Condition Specified Condition
      Relay block suspension control relay terminal 5 - Body ground Always 11 to 14 V
      Fig 2: Checking Harness And Connector (ECU - Compressor, Compressor - Battery And Body Ground)
      G04944151Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Disconnect the A57 compressor connector.
      Fig 3: Disconnecting A57 Compressor Connector
      G04944152Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    4. Disconnect the A39 ECU connector.
    5. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      ECU - COMPRESSOR, COMPRESSOR - BATTERY AND BODY GROUND RESISTANCE

      Tester Connection Condition Specified Condition
      Relay block suspension control relay terminal 3 - A57-1 (B) Always Below 1 Ω
      Relay block suspension control relay terminal 3 or A57-1 (B) -Body ground Always 10 kΩ or higher
      A57-2 (E) - Body ground Always Below 1 Ω
      A57-3 (RM+) - A39-17 (RM+) Always Below 1 Ω
      A57-3 (RM+) or A39-17 (RM+) -Body ground Always 10 kΩ or higher
      A57-4 (RM-) - A39-18 (RM-) Always Below 1 Ω
      A57-4 (RM-) or A39-18 (RM-) -Body ground Always 10 kΩ or higher

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: GO TO NEXT STEP 

  3. INSPECT HEIGHT CONTROL COMPRESSOR (COMPRESSOR MOTOR) 
    1. Remove the height control compressor (see REMOVAL  ).
    2. Connect terminal 1 (B) to the battery positive (+) terminal, and terminal 2 (E) to the battery negative (-) terminal.
    3. Check the operating of the compressor motor.
      Fig 4: Inspecting Height Control Compressor (Compressor Motor)
      G04944153Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      OK: Motor operates 

      NOTE:
      • Do not operate the height control compressor for 60 seconds or more.
      • Since a short and a lock-up inside the height control compressor cause excessive current to flow, stop operation immediately when it does not rotate.

    NG: REPLACE HEIGHT CONTROL COMPRESSOR (See  REMOVAL   ) 

    OK: REPLACE SUSPENSION CONTROL ECU (See  REMOVAL   ) 

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