ADAPTIVE VARIABLE SUSPENSION SYSTEM, Diagnostic DTC:C1789

DTC Code DTC Name
C1789 Vehicle Identification Malfunction

DESCRIPTION

When the absorber control ECU has not acquired the vehicle identification information, DTC C1789 is stored. When the vehicle identification information is correctly acquired, this DTC is cleared. Vehicle identification information is automatically acquired when the system enters test mode.

If an incorrect ECM, engine stop and start ECU, suspension control ECU, steering sensor, VGRS ECU (front steering control ECU)* or DRS ECU (rear steering control ECU)* is installed, the vehicle information will not match and DTC C1789 will be stored.


DTC No. Detection Item DTC Detection Condition Trouble Area Warning Indicate Memory
C1789 Vehicle Identification Malfunction

One of the following conditions is met:


  • The vehicle identification information is not stored.

  • Vehicle identification information that is different from the stored information is received 3 times.

  • Conventional/Hybrid vehicle information is not stored.

  • Received conventional/hybrid vehicle information value differs from stored value.

  • Stop and start system setting availability stored value is not stored.

  • Received stop and start system availability value differs from stored value.

  • Air suspension system setting availability stored value is not stored.

  • Received air suspension system availability value differs from stored value.

  • Variable gear ratio steering system setting availability stored value is not stored.

  • Received variable gear ratio steering system availability value differs from stored value.

  • Dynamic rear steering system setting availability stored value is not stored.

  • Received dynamic rear steering system availability value differs from stored value.

  • CAN communication system

  • Vehicle identification information

  • ECM

  • Engine stop and start ECU

  • Suspension control ECU

  • Steering sensor

  • Absorber control ECU

  • VGRS ECU (front steering control ECU)*

  • DRS ECU (rear steering control ECU)*

 Does not come on

Yes

(Under some of the detection conditions (control map non-retrieval, conventional/Hybrid vehicle information is not stored, air suspension system setting availability stored value is not stored, stop and start system setting availability stored value is not stored, variable gear ratio steering system setting availability stored value is not stored and dynamic rear steering system setting availability stored value is not stored), DTC is not stored.)

CAUTION / NOTICE / HINT

Note


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

  • If DTC C1782 (Power Source Voltage Malfunction) is output at the same time, perform troubleshooting for C1782 first.

    Click here

  • Before replacing the absorber control ECU, perform all of the following:


    • Symptom simulation.

      Click here

    • DTC inspection.

      Click here

    • GTS inspection.

      Click here


      • If no malfunctions are found in other areas, replace the absorber control ECU.

  • After replacing the absorber control ECU with a new one, perform registration of vehicle identification information.

    Click here

PROCEDURE


  1. CHECK FOR DTCS (CAN COMMUNICATION SYSTEM)


    1. Check for DTCs.

      Click here


      Chassis > Adaptive Variable Suspension System > Trouble Codes

      Tech Tips

      If DTC C1781 (Suspension Control ECU Malfunction) is output at the same time, perform troubleshooting for C1781 first.

      Result
      Result Proceed to
      C1781 and CAN communication malfunction DTC are not output A
      C1781 is output B
      CAN communication DTC is output C

    B

    GO TO C1781 Click here

    C

    GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) Click here

    A

  2. CHECK VEHICLE IDENTIFICATION INFORMATION STATUS


    1. Check that vehicle identification information has been stored.

      Click here

      Result
      Result Proceed to
      Information stored A
      Information not stored B

    B

    PERFORM VEHICLE IDENTIFICATION INFORMATION REGISTRATION Click here

    A

  3. CHECK RELATED PART


    1. If the DTC was output as a result of the replacement of a related part, replace the part with one that has a correct part number.

      Related Part ECM
      Engine stop and start ECU
      Suspension control ECU
      Steering sensor
      VGRS ECU (front steering control ECU)*
      DRS ECU (rear steering control ECU)*

      • *: w/ Variable Gear Ratio Steering System

      Note

      When removing a related part to check it, be sure to follow the appropriate procedures and precautions.



      • *: w/ Variable Gear Ratio Steering System

      Tech Tips

      If parts have not been replaced and DTC C1789 is output, there may be an internal malfunction in the absorber control ECU. Therefore, replace the absorber control ECU.

      Result
      Result Proceed to
      The related part has an incorrect part number. A
      The related part has the correct part number, or a related part and absorber control ECU have not been replaced. B

    A

    REPLACE RELATED PART WITH PART THAT HAS CORRECT PART NUMBER ECM Click here Engine stop and start ECU Click here Suspension control ECU Click here Steering sensor Click here VGRS ECU (front steering control ECU)* Click here DRS ECU (rear steering control ECU)* Click here *: w/ Variable Gear Ratio Steering System

    B

    REPLACE ABSORBER CONTROL ECU Click here