AIR SUSPENSION SYSTEM, Diagnostic DTC:C1746/46

DTC Code DTC Name
C1746/46 Gate Solenoid Valve Circuit

DESCRIPTION

The suspension control ECU opens the gate solenoid valve (No. 2 height control valve) to allow compressed air to flow into the height control cylinder (pneumatic cylinder) and raise the vehicle height.

The gate solenoid valve (No. 2 height control valve) opens and closes the passage between the right and left height control cylinders (pneumatic cylinders).

The No. 2 height control valve consists of a leveling solenoid valve and a gate solenoid valve.

The gate solenoid valve opens and closes the passage between the height control compressor and the height control cylinder (pneumatic cylinder).

DTC Code DTC Detection Condition Trouble Area
C1746/46

Either condition is met:


  • With the height control valve inactivated, 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 valve is detected 8 times successively.

  • Harness or connector

  • Gate solenoid valve (No. 2 height control valve)

  • Suspension control ECU

Tech Tips


  • Once the suspension control ECU stores DTC C1746/46 in memory, vehicle height control is suspended until a normal signal is input to the suspension control ECU from the height control valves. However, control is resumed if the ignition switch is turned off and then to ON again.

  • Malfunction in the gate solenoid valve:

    Height control operation is suspended and the height control indicator does not change by operating the height control switch.

WIRING DIAGRAM

A00O3ZDE05

INSPECTION PROCEDURE

Note

When replacing the suspension control ECU, perform registration Click here.

Tech Tips

If DTC C1782/82 is output at the same time as C1746/46, perform the inspection necessary for DTC C1782/82 first Click here.

PROCEDURE


  1. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (REAR GATE SOLENOID)


    1. Turn the ignition switch off.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the ignition switch to ON.

    4. Turn the intelligent tester on.

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

      Air Suspension
      Tester Display Test Part Control Range Diagnostic Note
      Rear Gate Solenoid Gate solenoid valve ON or OFF

      • The operating sound of the solenoid (clicking sound) can be heard.

      • When the Active Test is performed, Rear Gate Solenoid in the Data List changes between ON and OFF accordingly.
      OK
      Operation of solenoid (clicking sound) can be heard.
      Result
      Result Proceed to
      NG A
      OK (When troubleshooting according to problem symptoms table) B
      OK (When troubleshooting according to DTC chart) C

    B

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    C

    USE SIMULATION METHOD TO CHECK Click here

    A

  2. CHECK HARNESS AND CONNECTOR (GATE SOLENOID VALVE - SUSPENSION CONTROL ECU)


    1. Disconnect the S7 gate solenoid valve connector.

    2. Disconnect the A14 suspension control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      S7-1 (LH+) - A14-15 (SLRL) Always Below 1 Ω
      S7-1 (LH+) - Body ground Always 10 kΩ or higher
      S7-2 (E) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT NO. 2 HEIGHT CONTROL VALVE (GATE SOLENOID VALVE)


    1. Turn the ignition switch off.

    2. Remove the No. 2 height control valve Click here.

    3. A00O6CVE01
      Text in Illustration
      *a

      Component without harness connected

      (No. 2 Height Control Valve)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1 (LH+) - 2 (E) 20°C (68°F) 17.5 to 21.5 Ω

    4. Connect the positive (+) lead of the battery to terminal 1 (LH+) and the negative (-) lead to terminal 2 (E) of the solenoid valve connector. Then check that the valve makes an operating sound.

      OK
      Operation of solenoid (clicking sound) can be heard.

    NG

    REPLACE NO. 2 HEIGHT CONTROL VALVE ASSEMBLY Click here

    OK

    REPLACE SUSPENSION CONTROL ECU Click here