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

  • Integration control and panel (Damping mode select switch)

  • Suspension control ECU

WIRING DIAGRAM

A01EPVSE11

INSPECTION PROCEDURE

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 intelligent tester on.

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

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

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

      Damping mode select switch (SPORT) /

      ON or OFF

      ON: SPORT

      OFF: NORMAL or COMFORT

      		 -
      COMFORT Switch

      Damping mode select switch (COMFORT) /

      ON or OFF

      ON: COMFORT

      OFF: NORMAL or SPORT

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

    NG

    INSPECT INTEGRATION CONTROL AND PANEL (DAMPING MODE SELECT 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

    B

    USE SIMULATION METHOD TO CHECK Click here

    A

    REPLACE SUSPENSION CONTROL ECU Click here

  3. INSPECT INTEGRATION CONTROL AND PANEL (DAMPING MODE SELECT SWITCH)


    1. Remove the integration control and panel Click here.

    2. A01EP1PE12

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      3 (ECU1) - 8 (E) SPORT Below 1 Ω
      Except SPORT 10 kΩ or higher
      7 (ECU2) - 8 (E) COMF Below 1 Ω
      Except COMF 10 kΩ or higher

    NG

    REPLACE INTEGRATION CONTROL AND PANEL Click here

    OK

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

    A01EQ8PE09

    1. Disconnect the K30 ECU connector.

    2. Disconnect the V4 integration control and panel connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K30-2 (TSW1) - V4-3 (ECU1) Always Below 1 Ω
      K30-2 (TSW1) - Body ground Always 10 kΩ or higher
      K30-9 (TSW2) - V4-7 (ECU2) Always Below 1 Ω
      K30-9 (TSW2) - Body ground Always 10 kΩ or higher
      V4-8 (E) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE SUSPENSION CONTROL ECU Click here