ACTIVE HEIGHT CONTROL SUSPENSION, Diagnostic DTC:C1791

DTC Code DTC Name
C1791 Absorber Control Switch Circuit (Test Mode DTC)

DESCRIPTION

This circuit is used for sending the signal to the suspension control ECU to switch to the damping mode selected by the damping force control switch.

DTC Code Detection Condition Trouble Area
C1791 The test mode procedure is performed.

  • Harness or connector

  • Suspension control switch (Damping forcer control switch)

  • Suspension control ECU

WIRING DIAGRAM

B001YFQE07

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.

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (SPORT SWITCH, COMFORT SWITCH)


    1. Turn the engine switch off.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the engine switch on (IG) and the tester on.

    4. Enter the following menus: Chassis / AHC / Data List.

    5. According to the display on the tester, read the Data List.

      AHC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      SPORT Switch

      Damping force control switch (SPORT) /

      ON or OFF

      ON: SPORT

      OFF: NORMAL or COMFORT

      		 -
      COMFORT Switch

      Damping force control switch (COMFORT) /

      ON or OFF

      ON: COMFORT

      OFF: NORMAL or SPORT

      		 -
      OK
      On the tester screen, item changes between ON and OFF according to switch operation.

    NG

    INSPECT SUSPENSION CONTROL SWITCH (DAMPING FORCE CONTROL SWITCH) Click here

    OK

  2. TEST MODE INSPECTION


    1. Refer to the Test Mode Procedure and perform the signal check. Check that test mode DTC C1791 is cleared Click here.

      Result
      Result Proceed to
      DTC C1791 is not cleared A
      DTC C1791 is cleared B

    A

    REPLACE SUSPENSION CONTROL ECU Click here

    B

    USE SIMULATION METHOD TO CHECK Click here

  3. INSPECT SUSPENSION CONTROL SWITCH (DAMPING FORCE CONTROL SWITCH)


    1. Remove the suspension control switch Click here.

    2. A01X6PRE06
      *1 Component without harness connected: (Suspension Control Switch)

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      5 (ECU2) - 16 (E) COMF Below 1 Ω
      Except COMF 10 kΩ or higher
      6 (ECU1) - 16 (E) SPORT Below 1 Ω
      Except SPORT 10 kΩ or higher

    NG

    REPLACE SUSPENSION CONTROL SWITCH Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - SWITCH AND BODY GROUND)

    A01X6MOE02
    *1 Rear view of wire harness connector: (to Suspension Control ECU)
    *2 Front view of wire harness connector: (to Suspension Control Switch)

    1. Disconnect the K34 ECU connector.

    2. Disconnect the V4 switch connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K34-2 (TSW1) - V4-6 (ECU1) Always Below 1 Ω
      K34-2 (TSW1) - Body ground Always 10 kΩ or higher
      K34-9 (TSW2) - V4-5 (ECU2) Always Below 1 Ω
      K34-9 (TSW2) - Body ground Always 10 kΩ or higher
      V4-16 (E) - Body ground Always Below 1 Ω

    OK

    REPLACE SUSPENSION CONTROL ECU Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR