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Home >> Lexus >> 2021 >> GX 460 Premium >> Repair and Diagnosis >> Suspension >> Electronic Suspension >> Air Suspension System (Diagnostic Codes & Symptom Tests) >> Air Suspension System >> DTC C1792-92: Height Control Switch Circuit (Test Mode DTC) [08/2015 - 08/2019] >> Procedure

DTC C1792-92: Height Control Switch Circuit (Test Mode DTC) [08/2015 - 08/2019]: Procedure

  1. READ VALUE USING TECHSTREAM (HEIGHT CONTROL SWITCH) 
    1. Turn the engine switch off.
    2. Connect the Techstream to the DLC3.
    3. Turn the engine switch on (IG).
    4. Turn the Techstream on.
    5. Enter the following menus: Chassis / Air suspension / Data List.
      AIR SUSPENSION

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Height Control Switch (UP) Height control switch ("up" side) / ON or OFF ON: Switch is pressed and held
      OFF: Switch is not pressed
      -
      Height Control Switch (DOWN) Height control switch ("down" side) / ON or OFF ON: Switch is pressed and held
      OFF: Switch is not pressed
      -
    6. Check that the value displayed on the Techstream changes by pressing the height control switch "up" side or "down" side.

      OK

      Height control switch value changes.

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK 

    (Refer to HOW TO PROCEED WITH TROUBLESHOOTING [08/2015 - 08/2019] )

    Result: 

    NG 

    See step  2

  2. INSPECT HEIGHT CONTROL SWITCH (COMBINATION SWITCH) 
    1. Turn the engine switch off.
    2. Remove the combination switch (Refer to REMOVAL [08/2015 - 08/2021] ).
    3. Measure the resistance according to the value(s) in the table below.
      GTY625222Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      14 (LO) - 9 (E) "Down" pressed Below 1 Ω
      14 (LO) - 9 (E) "Up" pressed 10 kΩ or higher
      7 (HI) - 9 (E) "Down" pressed 10 kΩ or higher
      7 (HI) - 9 (E) "Up" pressed Below 1 Ω
      TEXT IN ILLUSTRATION

      *a Component without harness connected
      (Height Control Switch [Combination Switch])

    Result: 

    NG 

    REPLACE COMBINATION SWITCH ASSEMBLY 

    (Refer to REMOVAL [08/2015 - 08/2021] )

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (HEIGHT CONTROL SWITCH - SUSPENSION CONTROL ECU) 
    1. Disconnect the i5 combination switch connector.
    2. Disconnect the A40 suspension control ECU connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      i5-7 (HI) - A40-15 (UPSW) Always Below 1 Ω
      i5-14 (LO) - A40-14 (DNSW) Always Below 1 Ω
      i5-9 (E) - Body ground Always Below 1 Ω
      i5-7 (HI) - Body ground Always 10 kΩ or higher
      i5-14 (LO) - Body ground Always 10 kΩ or higher

    Result: 

    OK 

    REPLACE SUSPENSION CONTROL ECU 

    (Refer to REMOVAL [08/2015 - ] )

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR