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Home › Lexus › 2008 › LX 570 › Repair and Diagnosis › Suspension › Suspension Control Systems › Suspension Control › Active Height Control Suspension › DTC C1766 Height Control Pump Motor Current › Inspection Procedure

Inspection Procedure

NOTE:
  • If the suspension control ECU or height control sensor is replaced, the vehicle height offset calibration must be performed (See INITIALIZATION ).
  • When the cargo weight is extremely heavy, this DTC may be stored.
  1. INSPECT FOR FLUID LEAK 
    1. Inspect for fluid leaks (See ON-VEHICLE INSPECTION ).

    NG: REPAIR FLUID LEAK OR REPLACE LEAKING PART (S) 

    OK: Go to next Step 

  2. PERFORM ACTIVE TEST USING TECHSTREAM (LEVELING VALVE, ACCUMULATOR VALVE AND GATE VALVE) 
    1. Turn the engine switch off.
    2. Connect the Techstream to the DLC3.
    3. Start the engine and turn the Techstream on.
    4. Enter the following menus: Chassis / AHC / Active Test.
    5. Check the operation of the leveling valve solenoid, accumulator valve solenoid and gate valve solenoid when operating the solenoid with the Techstream.

    AHC 

    AHC REFERENCE

    Tester Display Test Part Control Range Diagnostic Note
    Front Right Height Solenoid Front height control solenoid valve RH ON or OFF Operation of the solenoid can be heard.
    Front Left Height Solenoid Front height control solenoid valve LH ON or OFF Operation of the solenoid can be heard.
    Rear Right Height Solenoid Rear height control solenoid valve RH ON or OFF Operation of the solenoid can be heard.
    Rear Left Height Solenoid Rear height control solenoid valve LH ON or OFF Operation of the solenoid can be heard.
    Accumulator Valve Accumulator solenoid valve ON or OFF Operation of the solenoid can be heard.
    Front Gate Valve Front gate solenoid valve ON or OFF When the Front Gate Valve item of the Active Test is operated, the Front Gate Valve item of the Data List changes to ON/OFF.
    Rear Gate Valve Rear gate solenoid valve ON or OFF When the Rear Gate Valve item of the Active Test is operated, the Rear Gate Valve item of the Data List changes to ON/OFF.

    OK: The leveling valve solenoid, accumulator valve solenoid and/or gate valve solenoid operates. 

    NG: REPLACE NO. 1 HEIGHT CONTROL VALVE  (See REMOVAL )

  3. INSPECT SUSPENSION CONTROL RELAY (AHC) 
    1. Remove the suspension control relay from the engine room relay block.
    2. Measure the resistance according to the value (s) in the table below.

    Standard Resistance 

    STANDARD RESISTANCE

    Tester Connection Condition Specified Condition
    3-5 Battery voltage is not applied to terminal 1 and 2 10 kΩ or higher
    Battery voltage is applied to terminal 1 and 2 Below 1 Ω

    NG: REPLACE SUSPENSION CONTROL RELAY 

    Fig 1: Inspecting Suspension Control Relay (AHC)
    G04944147Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to next Step 

  4. CHECK OPERATION OF HEIGHT CONTROL PUMP AND MOTOR 
    1. Remove the height control pump and motor (See REMOVAL ).
    2. Inspect if the compressor is stuck.
      1. Apply battery voltage to the compressor motor and check the operation of the motor.

    OK 

    MEASUREMENT CONDITION AND SPECIFIED CONDITION

    Measurement Condition Specified Condition
    Battery positive (+) → Terminal 2
    Battery negative (-) → Terminal 1    		 Motor operates
    NOTE:
    • Do not allow the motor to operate for 60 seconds or more.
    • If the height control pump and motor is shorted, locked, or has a similar type of malfunction, a large amount of current will be flowing. Therefore, if the motor does not operate, immediately stop this inspection.
    Fig 2: Identifying Height Control Pump And Motor Connector Terminals
    G05761332Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE HEIGHT CONTROL PUMP AND MOTOR  (See REMOVAL )

    OK: Go to next Step 

  5. INSPECT FLUID LINE 
    1. Check if the fluid line is clogged.

    HINT:

    • Check if the fluid line that connects the height control pump and motor and No. 1 height control valve is clogged. If it is not clogged, there probably is foreign matter clogging the interior of the No. 1 height control valve.
    • Follow the removal and installation procedures for each part, as all parts need to be removed.

    NG: REPAIR OR REPLACE CLOGGED PARTS 

    OK: REPLACE SUSPENSION CONTROL ECU  (See REMOVAL )

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