ACTIVE HEIGHT CONTROL SUSPENSION, Diagnostic DTC:C1741, C1742, C1743, C1744, C1753, C1754, C1755

DTC Code DTC Name
C1741 Front Height Control Solenoid Valve RH Circuit Malfunction
C1742 Front Height Control Solenoid Valve LH Circuit Malfunction
C1743 Rear Height Control Solenoid Valve RH Circuit Malfunction
C1744 Rear Height Control Solenoid Valve LH Circuit Malfunction
C1753 Accumulator Solenoid Valve Malfunction
C1754 Front Gate Solenoid Valve Malfunction
C1755 Rear Gate Solenoid Valve Malfunction

DESCRIPTION

The control valve solenoid assembly consists of each front and rear leveling valve, gate valve and accumulator valve. It performs the height control and connects and disconnects the fluid line of the right and left shock absorber by operating the solenoid valve with the control signal from the ECU.

DTC Code Detection Condition Trouble Area
C1741

When either of the following is detected:


  • With the front leveling valve RH not activated, an open signal of the front leveling valve RH is detected for 1 second or more.

  • With the front leveling valve RH activated, a short signal of the front leveling valve RH is detected 8 times successively.

  • Harness or connector

  • No. 1 height control valve

  • Suspension control ECU

  • Each front suspension control valve (Each front spring rate switching valve)
C1742

When either of the following is detected:


  • With the front leveling valve LH not activated, an open signal of the front leveling valve LH is detected for 1 second or more.

  • With the front leveling valve LH activated, a short signal of the front leveling valve LH is detected 8 times successively.

  • Harness or connector

  • No. 1 height control valve

  • Suspension control ECU

  • Each front suspension control valve (Each front spring rate switching valve)
C1743

When either of the following is detected:


  • With the rear leveling valve RH not activated, an open signal of the rear leveling valve RH is detected for 1 second or more.

  • With the rear leveling valve RH activated, a short signal of the rear leveling valve RH is detected 8 times successively.

  • Harness or connector

  • No. 1 height control valve

  • Suspension control ECU

  • Each front suspension control valve (Each front spring rate switching valve)
C1744

When either of the following is detected:


  • With the rear leveling valve LH not activated, an open signal of the rear leveling valve LH is detected for 1 second or more.

  • With the rear leveling valve LH activated, a short signal of the rear leveling valve LH is detected 8 times successively.

  • Harness or connector

  • No. 1 height control valve

  • Suspension control ECU

  • Each front suspension control valve (Each front spring rate switching valve)
C1753

When either of the following is detected:


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

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

  • Harness or connector

  • No. 1 height control valve

  • Suspension control ECU

  • Each front suspension control valve (Each front spring rate switching valve)
C1754

When either of the following is detected:


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

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

  • Harness or connector

  • No. 1 height control valve

  • Suspension control ECU

  • Each front suspension control valve (Each front spring rate switching valve)
C1755

When either of the following is detected:


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

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

  • Harness or connector

  • No. 1 height control valve

  • Suspension control ECU

  • Each front suspension control valve (Each front spring rate switching valve)

WIRING DIAGRAM

B001Z96E07

CAUTION / NOTICE / HINT

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.

Tech Tips

Power is supplied to the No. 1 height control valve and front suspension control valve from the suspension control ECU. If a short occurs in the power supply circuit in the front suspension control valve, DTC C1741, C1742, C1743, C1744, C1753, C1754 and/or C1755 will be stored. In this case, DTC C1736 and/or C1737 will also be stored.

PROCEDURE


  1. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (NO. 1 HEIGHT CONTROL VALVE)


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine and turn the tester on.

    3. Select the Active Test mode on the intelligent tester.

    4. 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 solenoid can be heard.
      Front Left Height Solenoid Front height control solenoid valve LH ON or OFF Operation of solenoid can be heard.
      Rear Right Height Solenoid Rear height control solenoid valve RH ON or OFF Operation of solenoid can be heard.
      Rear Left Height Solenoid Rear height control solenoid valve LH ON or OFF Operation of solenoid can be heard.
      Accumulator Valve Accumulator solenoid valve ON or OFF Operation of 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 solenoid and/or gate valve solenoid operates.

    NG

    CHECK HARNESS AND CONNECTOR (NO. 1 HEIGHT CONTROL VALVE - SUSPENSION CONTROL ECU) Click here

    OK

  2. RECONFIRM DTC OUTPUT


    1. Clear the DTCs Click here.

    2. Perform a road test.

    3. Check for DTCs.

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

    A

    REPLACE SUSPENSION CONTROL ECU Click here

    B

    USE SIMULATION METHOD TO CHECK Click here

  3. CHECK HARNESS AND CONNECTOR (NO. 1 HEIGHT CONTROL VALVE - SUSPENSION CONTROL ECU)


    1. Disconnect the N4 No. 1 height control valve connector.

    2. Disconnect the K36 ECU connector.

      B001YQEE02

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K36-1 (SLB) - N4-6 (SLB) Always Below 1 Ω
      K36-7 (SLFR) - N4-4 (SLFR) Always Below 1 Ω
      K36-7 (SLFR) - Body ground Always 10 kΩ or higher
      K36-8 (SLFL) - N4-3 (SLFL) Always Below 1 Ω
      K36-8 (SLFL) - Body ground Always 10 kΩ or higher
      K36-9 (SLRR) - N4-1 (SLRR) Always Below 1 Ω
      K36-9 (SLRR) - Body ground Always 10 kΩ or higher
      K36-10 (SLAC) - N4-7 (AHC-) Always Below 1 Ω
      K36-10 (SLAC) - Body ground Always 10 kΩ or higher
      K36-22 (SLRL) - N4-2 (SLRL) Always Below 1 Ω
      K36-22 (SLRL) - Body ground Always 10 kΩ or higher
      K36-29 (SLRG) - N4-5 (SLRG) Always Below 1 Ω
      K36-29 (SLRG) - Body ground Always 10 kΩ or higher
      K36-30 (SLFG) - N4-8 (SLFG) Always Below 1 Ω
      K36-30 (SLFG) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (BODY GROUND BETWEEN ECU - NO. 1 HEIGHT CONTROL VALVE)


    1. Disconnect the N4 No. 1 height control valve connector.

    2. B001YBDE01
      *a Rear view of wire harness connector: (to Suspension Control ECU)
      *b 1 (SLB)

      Disconnect the K36 ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K36-1 (SLB) - Body ground Always 10 kΩ or higher

    NG

    CHECK HARNESS AND CONNECTOR (BODY GROUND BETWEEN ECU - FRONT SUSPENSION CONTROL VALVE) Click here

    OK

  5. INSPECT NO. 1 HEIGHT CONTROL VALVE


    1. Connect the N4 No. 1 height control valve connector.

    2. Disconnect the K36 ECU connector.

    3. B001Z0EE02

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K36-7 (SLFR) - K36-1 (SLB) Always 3 to 3.8 Ω
      K36-7 (SLFR) - Body ground Always 10 kΩ or higher
      K36-8 (SLFL) - K36-1 (SLB) Always 3 to 3.8 Ω
      K36-8 (SLFL) - Body ground Always 10 kΩ or higher
      K36-9 (SLRR) - K36-1 (SLB) Always 3 to 3.8 Ω
      K36-9 (SLRR) - Body ground Always 10 kΩ or higher
      K36-10 (SLAC) - K36-1 (SLB) Always 3 to 3.8 Ω
      K36-10 (SLAC) - Body ground Always 10 kΩ or higher
      K36-22 (SLRL) - K36-1 (SLB) Always 3 to 3.8 Ω
      K36-22 (SLRL) - Body ground Always 10 kΩ or higher
      K36-29 (SLRG) - K36-1 (SLB) Always 3 to 3.8 Ω
      K36-29 (SLRG) - Body ground Always 10 kΩ or higher
      K36-30 (SLFG) - K36-1 (SLB) Always 3 to 3.8 Ω
      K36-30 (SLFG) - Body ground Always 10 kΩ or higher
      K36-1 (SLB) - Body ground Always 10 kΩ or higher

    OK

    REPLACE SUSPENSION CONTROL ECU Click here

    NG

    REPLACE NO. 1 HEIGHT CONTROL VALVE Click here

  6. CHECK HARNESS AND CONNECTOR (BODY GROUND BETWEEN ECU - FRONT SUSPENSION CONTROL VALVE)


    1. Disconnect the N10 and N12 front suspension control valve connectors.

    2. Disconnect the N4 No. 1 height control valve connector.

    3. Disconnect the K36 ECU connector.

    4. B001YEDE01
      *a Rear view of wire harness connector: (to Suspension Control ECU)
      *b 1 (SLB)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K36-1 (SLB) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - FRONT SUSPENSION CONTROL VALVE)


    1. Disconnect the N10*1 and/or N12*2 front suspension control valve connector.

      Tech Tips

      *1: for RH

      *2: for LH

    2. Disconnect the K36 ECU connector.

      B001ZS5E02

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K36-11 (CRFR) - N10-1 (CRFR) Always Below 1 Ω
      K36-11 (CRFR) - Body ground Always 10 kΩ or higher
      K36-23 (CRFL) - N12-1 (CRFL) Always Below 1 Ω
      K36-23 (CRFL) - Body ground Always 10 kΩ or higher
      K36-1 (SLB) - N10-2 (SLB) Always Below 1 Ω
      K36-1 (SLB) - N12-2 (SLB) Always Below 1 Ω

    OK

    REPLACE FRONT SUSPENSION CONTROL VALVE

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR