AIR SUSPENSION SYSTEM, Diagnostic DTC:C1743, C1744

DTC Code DTC Name
C1743 Rear Height Control Solenoid Valve RH Circuit Malfunction
C1744 Rear Height Control Solenoid Valve LH Circuit Malfunction

DESCRIPTION

The No. 2 height control valve independently opens and closes paths to the pneumatic cylinder for the rear wheel side by receiving signals from the suspension control ECU.

DTC No. Detection Condition Trouble Area
C1743/43

When either of the following is detected:


  • With the height control valve not activated, an open signal of the height control valve is detected for 1 second or more.

  • With the height control valve activated, a short signal of the height control valve is detected 8 times successively.

  • No. 2 height control valve

  • Wire harness or connector

  • Suspension control ECU
C1744/44

When either of the following is detected:


  • With the height control valve not activated, an open signal of the height control valve is detected for 1 second or more.

  • With the height control valve activated, a short signal of the height control valve is detected 8 times successively.

  • No. 2 height control valve

  • Wire harness or connector

  • Suspension control ECU

WIRING DIAGRAM

A01GM6JE11

INSPECTION PROCEDURE

Note


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

  • If DTC C1782/82 (Power Source Voltage Malfunction) is output at the same time, perform troubleshooting for C1782/82 first Click here.

  • Before replacing the suspension control ECU, perform all of the following again: 1) symptom simulation Click here; 2) DTC inspection; and 3) intelligent tester inspection (ECU 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 Click here.

PROCEDURE


  1. CLEAR DTC


    1. Clear the DTC Click here.


    NEXT

  2. CHECK NO. 2 HEIGHT CONTROL VALVE OPERATION (ACTIVE TEST)


    1. Turn the engine switch off.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the engine switch on (IG) and turn the tester main switch on.

    4. Enter the following menus:

      Select: Chassis / Air suspension / Active Test /

    5. Check the operation sound of the height control solenoid valve when the solenoid is turned on through the Active Test.

      Air Suspension
      Tester Display Test Part Control Range Diagnostic Note
      Rear Right Solenoid No. 2 height control valve RH - Operation of solenoid (clicking sound) can be heard
      Rear Left Solenoid No. 2 hight control valve LH - Operation of solenoid (clicking sound) can be heard
      OK
      An operation sound is heard 1 second after the height control solenoid valve is turned on.

    NG

    INSPECT NO. 2 HEIGHT CONTROL VALVE Click here

    OK

  3. RECONFIRM DTC


    1. Perform a road test.

    2. Check for DTC Click here.

      Result
      Condition Proceed to
      DTC is output A
      DTC is not output B

    B

    USE SIMULATION METHOD TO CHECK Click here

    A

  4. INSPECT NO. 2 HEIGHT CONTROL VALVE


    1. A01GIVNE33

      Remove the No. 2 height control valve Click here.

    2. Measure the resistance according to the values in the table below.

      Standard resistance
      C1743/43:
      Tester Connection Condition Specified Condition
      1 (RH+) - 2 (E) at 20°C (68°F) 10 to 14 Ω
      C1744/44:
      Tester Connection Condition Specified Condition
      3 (LH+) - 2 (E) at 20°C (68°F) 10 to 14 Ω

    NG

    REPLACE NO. 2 HEIGHT CONTROL VALVE Click here

    OK

  5. CHECK HARNESS AND CONNECTOR (NO. 2 HEIGHT CONTROL VALVE - ECU AND BODY GROUND)


    1. Disconnect the L88 ECU connector.

    2. Disconnect the j1 height control valve connector.

    3. Measure the resistance according to the values in the table below.

      A01GILWE12
      Standard resistance
      C1743/43:
      Tester Connection Condition Specified Condition
      L88-26 (SLRR) - j1-1 (RH+) Always Below 1 Ω
      L88-26 (SLRR) or j1-1 (RH+) - Body ground Always 10 kΩ or higher
      j1-2 (E) - Body ground Always Below 1 Ω
      C1744/44:
      Tester Connection Condition Specified Condition
      L88-25 (SLRL) - j1-3 (LH+) Always Below 1 Ω
      L88-25 (SLRL) or j1-3 (LH+) - Body ground Always 10 kΩ or higher
      j1-2 (E) - Body ground Always Below 1 Ω
      Result
      Result Proceed to
      NG A
      OK (for LHD) B
      OK (for RHD) C

    B

    REPLACE SUSPENSION CONTROL ECU (for LHD) Click here

    C

    REPLACE SUSPENSION CONTROL ECU (for RHD) Click here

    A

    REPAIR OR REPLACE HARNESS OR CONNECTOR