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ACTIVE HEIGHT CONTROL SUSPENSION, Diagnostic DTC:C1731, C1732, C1733, C1734

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DTC Code DTC Name
C1731 Front Damping Force Control Actuator RH Circuit Malfunction
C1732 Front Damping Force Control Actuator LH Circuit Malfunction
C1733 Rear Damping Force Control Actuator RH Circuit Malfunction
C1734 Rear Damping Force Control Actuator LH Circuit Malfunction
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DESCRIPTION

The ECU sends a signal to the damping force control actuator to drive the rotary valve of the shock absorber changing the shock absorber damping force.

The actuator is driven electromagnetically by a step motor so that it can accurately follow the driving conditions that change frequently.

DTC Code Detection Condition Trouble Area
C1731

When either of the following is detected:


  • An actuator open-circuit signal is detected for at least 1 second when the actuator operates.

  • An actuator short-circuit signal is consecutively detected 8 times when the actuator operates.

  • Harness or connector

  • Front shock absorber control valve RH (Front damping force control actuator RH)

  • Suspension control ECU
C1732

When either of the following is detected:


  • An actuator open-circuit signal is detected for at least 1 second when the actuator operates.

  • An actuator short-circuit signal is consecutively detected 8 times when the actuator operates.

  • Harness or connector

  • Front shock absorber control valve LH (Front damping force control actuator LH)

  • Suspension control ECU
C1733

When either of the following is detected:


  • An actuator open-circuit signal is detected for at least 1 second when the actuator operates.

  • An actuator short-circuit signal is consecutively detected 8 times when the actuator operates.

  • Harness or connector

  • Rear shock absorber control valve RH (Rear damping force control actuator RH)

  • Suspension control ECU
C1734

When either of the following is detected:


  • An actuator open-circuit signal is detected for at least 1 second when the actuator operates.

  • An actuator short-circuit signal is consecutively detected 8 times when the actuator operates.

  • Harness or connector

  • Rear shock absorber control valve LH (Rear damping force control actuator LH)

  • Suspension control ECU
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WIRING DIAGRAM

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INSPECTION PROCEDURE

Note:

  • Before performing troubleshooting, inspect the connectors of related circuits.

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

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PROCEDURE


  1. Click here

    PERFORM ACTIVE TEST USING INTELLIGENT TESTER (DAMPER STEP)


    1. According to the display on the intelligent tester, perform the Active Test.

    2. Check if the damping force control actuator operates in accordance with the Active Test.

      Table 1. AHC
      Tester Display Test Part Control Range Diagnostic Note
      Damper Step FR Changes front damper RH step

      min.: 1 step

      max.: 16 step

      		 The Damper Step item of the Data List changes to the step selected in the Active Test.
      Damper Step FL Changes front damper LH step

      min.: 1 step

      max.: 16 step

      		 The Damper Step item of the Data List changes to the step selected in the Active Test.
      Damper Step RR Changes rear damper RH step

      min.: 1 step

      max.: 16 step

      		 The Damper Step item of the Data List changes to the step selected in the Active Test.
      Damper Step RL Changes rear damper LH step

      min.: 1 step

      max.: 16 step

      		 The Damper Step item of the Data List changes to the step selected in the Active Test.
      OK
      The damping force control actuator operates.

  2. Click here

    RECONFIRM DTC OUTPUT


    1. Clear the DTCs (Click here).

    2. Perform a road test.

    3. Check for DTCs.

      Table 2. Result
      Result Proceed to
      DTC is output A
      DTC is not output B

  3. Click here

    CHECK HARNESS AND CONNECTOR (DAMPING FORCE CONTROL ACTUATOR - SUSPENSION CONTROL ECU)


    1. Check the front side damping force control actuator.


      1. Disconnect the N9 and/or N11 actuator connector.

      2. A0156SCE01

        Disconnect the K36 ECU connector.

      3. Measure the resistance according to the value(s) in the table below.

        Standard Resistance
        Table 3. for RH (C1731)
        Tester Connection Condition Specified Condition
        K36-5 (FAR-) - N9-4 (FAR-) Always Below 1 Ω
        K36-5 (FAR-) - Body ground Always 10 kΩ or higher
        K36-6 (FAR+) - N9-1 (FAR+) Always Below 1 Ω
        K36-6 (FAR+) - Body ground Always 10 kΩ or higher
        K36-17 (FBR-) - N9-3 (FBR-) Always Below 1 Ω
        K36-17 (FBR-) - Body ground Always 10 kΩ or higher
        K36-18 (FBR+) - N9-5 (FBR+) Always Below 1 Ω
        K36-18 (FBR+) - Body ground Always 10 kΩ or higher
        N9-2 (E FR) - Body ground Always Below 1 Ω
        Table 4. for LH (C1732)
        Tester Connection Condition Specified Condition
        K36-2 (FBL+) - N11-5 (FBL+) Always Below 1 Ω
        K36-2 (FBL+) - Body ground Always 10 kΩ or higher
        K36-3 (FAL-) - N11-4 (FAL-) Always Below 1 Ω
        K36-3 (FAL-) - Body ground Always 10 kΩ or higher
        K36-4 (FAL+) - N11-1 (FAL+) Always Below 1 Ω
        K36-4 (FAL+) - Body ground Always 10 kΩ or higher
        K36-12 (FBL-) - N11-3 (FBL-) Always Below 1 Ω
        K36-12 (FBL-) - Body ground Always 10 kΩ or higher
        N11-2 (E FL) - Body ground Always Below 1 Ω

    2. Check the rear side damping force control actuator.


      1. Disconnect the N6 and/or N8 actuator connector.

      2. A0156WEE01

        Disconnect the K35 ECU connector.

      3. Measure the resistance according to the value(s) in the table below.

        Standard Resistance
        Table 5. for RH (C1733)
        Tester Connection Condition Specified Condition
        K35-4 (RBR-) - N6-3 (RBR-) Always Below 1 Ω
        K35-4 (RBR-) - Body ground Always 10 kΩ or higher
        K35-5 (RAR+) - N6-1 (RAR+) Always Below 1 Ω
        K35-5 (RAR+) - Body ground Always 10 kΩ or higher
        K35-13 (RBR+) - N6-5 (RBR+) Always Below 1 Ω
        K35-13 (RBR+) - Body ground Always 10 kΩ or higher
        K35-14 (RAR-) - N6-4 (RAR-) Always Below 1 Ω
        K35-14 (RAR-) - Body ground Always 10 kΩ or higher
        N6-2 (E RR) - Body ground Always Below 1 Ω
        Table 6. for LH (C1734)
        Tester Connection Condition Specified Condition
        K35-2 (RAL-) - N8-4 (RAL-) Always Below 1 Ω
        K35-2 (RAL-) - Body ground Always 10 kΩ or higher
        K35-3 (RAL+) - N8-1 (RAL+) Always Below 1 Ω
        K35-3 (RAL+) - Body ground Always 10 kΩ or higher
        K35-7 (RBL-) - N8-3 (RBL-) Always Below 1 Ω
        K35-7 (RBL-) - Body ground Always 10 kΩ or higher
        K35-8 (RBL+) - N8-5 (RBL+) Always Below 1 Ω
        K35-8 (RBL+) - Body ground Always 10 kΩ or higher
        N8-2 (E RL) - Body ground Always Below 1 Ω

  4. Click here

    INSPECT DAMPING FORCE CONTROL ACTUATOR


    1. Check the front side damping force control actuator.


      1. Connect the N9 and/or N11 front absorber control actuator connector.

      2. A015BDXE01

        Disconnect the K36 ECU connector.

      3. Measure the resistance according to the value(s) in the table below.

        Standard Resistance
        Table 7. for RH (C1731)
        Tester Connection Condition Specified Condition
        K36-5 (FAR-) - Body ground Always 12.0 to 13.6 Ω
        K36-6 (FAR+) - Body ground Always 12.0 to 13.6 Ω
        K36-17 (FBR-) - Body ground Always 12.0 to 13.6 Ω
        K36-18 (FBR+) - Body ground Always 12.0 to 13.6 Ω
        Table 8. for LH (C1732)
        Tester Connection Condition Specified Condition
        K36-2 (FBL+) - Body ground Always 12.0 to 13.6 Ω
        K36-3 (FAL-) - Body ground Always 12.0 to 13.6 Ω
        K36-4 (FAL+) - Body ground Always 12.0 to 13.6 Ω
        K36-12 (FBL-) - Body ground Always 12.0 to 13.6 Ω

    2. Check the rear side damping force control actuator.


      1. Connect the N6 and/or N8 rear absorber control actuator connector.

      2. A01569QE01

        Disconnect the K35 ECU connector.

      3. Measure the resistance according to the value(s) in the table below.

        Standard Resistance
        Table 9. for RH (C1733)
        Tester Connection Condition Specified Condition
        K35-4 (RBR-) - Body ground Always 12.0 to 13.6 Ω
        K35-5 (RAR+) - Body ground Always 12.0 to 13.6 Ω
        K35-13 (RBR+) - Body ground Always 12.0 to 13.6 Ω
        K35-14 (RAR-) - Body ground Always 12.0 to 13.6 Ω
        Table 10. for LH (C1734)
        Tester Connection Condition Specified Condition
        K35-2 (RAL-) - Body ground Always 12.0 to 13.6 Ω
        K35-3 (RAL+) - Body ground Always 12.0 to 13.6 Ω
        K35-7 (RBL-) - Body ground Always 12.0 to 13.6 Ω
        K35-8 (RBL+) - Body ground Always 12.0 to 13.6 Ω
      Table 11. Result
      Result Proceed to
      OK A
      Front damping force control actuator RH malfunction B
      Front damping force control actuator LH malfunction C
      Rear damping force control actuator RH malfunction D
      Rear damping force control actuator LH malfunction E

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    REPAIR OR REPLACE HARNESS OR CONNECTOR

  6. Click here

    REPLACE FRONT SHOCK ABSORBER CONTROL VALVE RHClick here

  7. Click here

    REPLACE FRONT SHOCK ABSORBER CONTROL VALVE LHClick here

  8. Click here

    REPLACE REAR SHOCK ABSORBER CONTROL VALVE RHClick here

  9. Click here

    REPLACE REAR SHOCK ABSORBER CONTROL VALVE LHClick here

  10. Click here

    REPLACE SUSPENSION CONTROL ECUClick here

  11. Click here

    USE SIMULATION METHOD TO CHECKClick here