AIR SUSPENSION SYSTEM, Diagnostic DTC:C1794

DTC Code DTC Name
C1794 Height Control OFF Switch Circuit (Test Mode DTC)

DESCRIPTION

If the height control OFF switch is pressed when the vehicle is stopped with the power switch on (READY) or the power switch on (IG), vehicle height control will be disabled and remain disabled even after the power switch is turned off. In this case, "HEIGHT CONTROL OFF" will be displayed on the multi-information display in the combination meter assembly. Pressing the height control OFF switch again with the power switch on (READY) or the power switch on (IG) will resume the vehicle height control. If the vehicle speed reaches approximately 30 km/h when the vehicle height control is disabled, vehicle height control will automatically resume.

DTC No. DTC Detecting Condition Trouble Area
C1794 Detected only during Test Mode.

  • Height control OFF switch

  • Harness or connector

  • Suspension control ECU

WIRING DIAGRAM

A01ND28E01

INSPECTION PROCEDURE

Note


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

  • 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 OFF SWITCH


    1. A01NERQE03
      Text in Illustration
      *1

      Component without harness connected

      (Height Control OFF Switch)

      Disconnect the height control OFF switch connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      2 (MSW) - 1 (E) Height control OFF switch while pressing button Below 1 Ω
      Neutral position 10 kΩ or higher

    NG

    REPLACE HEIGHT CONTROL OFF SWITCH Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (HEIGHT CONTROL OFF SWITCH - ECU AND BODY GROUND)


    1. A01NDGYE02
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Height Control Switch)
      *2

      Rear view of wire harness connector

      (to Suspension Control ECU)

      Disconnect the A56 ECU connector.

    2. Disconnect the F18 height control OFF switch connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      F18-2 (MSW) - A56-13 (TD) Always Below 1 Ω
      A56-13 (TD) - Body ground Always 10 kΩ or higher
      Result
      Condition Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

    B

    REPLACE SUSPENSION CONTROL ECU (for RHD) Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

    REPLACE SUSPENSION CONTROL ECU (for LHD) Click here