ACTIVE HEIGHT CONTROL SUSPENSION, Diagnostic DTC:C1766

DTC Code DTC Name
C1766 Height Control Pump Motor Current

DESCRIPTION

In case that the height control has not finished in spite of performing the raise control for a certain period of time, the ECU interrupts the height control.

DTC Code Detection Condition Trouble Area
C1766 When the height control pump and motor operates continuously for 135 seconds.

  • Fluid leakage

  • No. 1 height control valve

  • Suspension control relay

  • Height control pump and motor

  • Clog in the fluid line

  • Suspension control ECU

CAUTION / NOTICE / HINT

Note


  • If the suspension control ECU or height control sensor is replaced, the vehicle height offset calibration must be performed Click here.

  • When the cargo weight is extremely heavy, this DTC may be stored.

PROCEDURE


  1. INSPECT FOR FLUID LEAK


    1. Inspect for fluid leaks Click here.


    NG

    REPAIR FLUID LEAK OR REPLACE LEAKING PART(S)

    OK

  2. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (LEVELING VALVE, ACCUMULATOR VALVE AND GATE VALVE)


    1. Turn the engine switch off.

    2. Connect the intelligent tester to the DLC3.

    3. Start the engine and turn the intelligent tester 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 intelligent tester.

      AHC
      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 Click here

    OK

  3. INSPECT SUSPENSION CONTROL RELAY (AHC)


    1. B001AY3E01

      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
      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

    OK

  4. CHECK OPERATION OF HEIGHT CONTROL PUMP AND MOTOR


    1. Remove the height control pump and motor Click here.

    2. Inspect if the compressor is stuck.


      1. B0018HQE01
        *1 Component without harness connected: (Height Control Pump and Motor)

        Apply battery voltage to the compressor motor and check the operation of the motor.

        OK
        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.


    NG

    REPLACE HEIGHT CONTROL PUMP AND MOTOR Click here

    OK

  5. INSPECT FLUID LINE


    1. Check if the fluid line is clogged.

      Tech Tips


      • 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.


    OK

    REPLACE SUSPENSION CONTROL ECU Click here

    NG

    REPAIR OR REPLACE CLOGGED PARTS