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

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

  • Harness or connector

  • Suspension control ECU
C1744

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

  • Harness or connector

  • Suspension control ECU

WIRING DIAGRAM

A01GZKGE06

INSPECTION PROCEDURE

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

    2. Connect the intelligent tester to the DLC3.

    3. Turn the power switch ON (IG) and the tester ON.

    4. Enter the following menus: Chassis / Air suspension / Active Test.

    5. According to the display on tester, perform the "Active Test".

    6. 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 ON or OFF Operation of solenoid (clicking sound) can be heard
      Rear Left Solenoid No. 2 heigh control valve LH ON or OFF 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

    USE SIMULATION METHOD TO CHECK Click here

  3. INSPECT NO. 2 HEIGHT CONTROL VALVE


    1. A01H05LE51

      Remove the No. 2 height control valve Click here.

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

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

    NG

    REPLACE NO. 2 HEIGHT CONTROL VALVE Click here

    OK

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


    1. Disconnect the L88 ECU connector.

    2. Disconnect the z14 height control valve connector.

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

      A01H1OUE14
      Standard resistance
      C1743:
      Tester Connection Condition Specified Condition
      L88-26 (SLRR) - z14-1 (+RH) Always Below 1 Ω
      L88-26 (SLRR) or z14-1 (+RH) - Body ground Always 10 kΩ or higher
      z14-2 (E) - Body ground Always Below 1 Ω
      C1744:
      Tester Connection Condition Specified Condition
      L88-25 (SLRL) - z14-3 (+LH) Always Below 1 Ω
      L88-25 (SLRL) or z14-3 (+LH) - Body ground Always 10 kΩ or higher
      z14-2 (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 Click here

    C

    REPLACE SUSPENSION CONTROL ECU Click here

    A

    REPAIR OR REPLACE HARNESS OR CONNECTOR