AIR SUSPENSION SYSTEM, Diagnostic DTC:C1745

DTC Code DTC Name
C1745 Exhaust Solenoid Valve Circuit Malfunction

DESCRIPTION

The exhaust valve built into the height control compressor assembly opens to discharge compressed air from the pneumatic cylinders into the atmosphere according to the signal from the suspension control ECU.

DTC No. DTC Detection Condition Trouble Area
C1745

When either of the following is detected:


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

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


  • Height control compressor assembly (Exhaust valve)

  • Wire harness or connector

  • Suspension control ECU

WIRING DIAGRAM

A01NHA6E02

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 Click here; and 3) Intelligent tester inspection (Data List or Active Test) Click here. If no malfunctions are found in other areas, replace the suspension control ECU.

  • If the suspension control ECU is replaced, the vehicle height offset calibration and registration of vehicle identification information must be performed Click here and Click here

PROCEDURE


  1. INSPECT HEIGHT CONTROL COMPRESSOR ASSEMBLY (EXHAUST VALVE)


    1. Turn the power switch off.

    2. A01NHQXE06
      Text in Illustration
      *1

      Component without harness connected

      (Exhaust Valve)

      Disconnect the exhaust valve connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      2 (B) - 1 (L) at 15 to 25°C (59 to 77°F) 10 to 14 Ω
    4. Inspect if the exhaust valve is stuck:


      1. Connect a positive (+) lead from the battery to terminal 2 (B) and a negative (-) lead to terminal 1 (L).

      2. Check the operating sound of the exhaust valve.

        OK
        It makes an operating sound (click).

    NG
    OK
  2. CHECK HARNESS AND CONNECTOR (EXHAUST VALVE - SUSPENSION CONTROL ECU AND BODY GROUND)


    1. Turn the power switch off.

    2. Disconnect the A54 ECU connector.

    3. Disconnect the O27 exhaust solenoid valve connector.

    4. A01NF2KE03
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Exhaust Valve)

      *2

      Rear view of wire harness connector

      (to Suspension Control ECU)

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

      Standard resistance
      Tester Connection Condition Specified Condition
      O27-2 (B) - A54-9 (SLEX) Always Below 1 Ω
      A54-9 (SLEX) - Body ground Always 10 kΩ or higher
      O27-1 (L) - Body ground Always Below 1 Ω
      Result
      Condition Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

    B
    C
    A