Dtc C1787 Ems Switch Circuit (Test Mode Dtc)

Suspension & Axle. Lexus Gs430, Gs300. Uzs190 Grs190
Suspension Control. Lexus Gs430, Gs300. Uzs190 Grs190

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE OF INTELLIGENT TESTER

RECONFIRM DTC

INSPECT ABSORBER CONTROL SWITCH

CHECK HARNESS AND CONNECTOR (ABSORBER CONTROL SWITCH TO ABSORBER CONTROL ECU, BODY GROUND)

RECONFIRM DTC

DTC C1787 EMS Switch Circuit (Test Mode DTC)


DESCRIPTION

  1. The absorber control switch (EMS Switch) is a switch which selects the damping force mode of shock absorber.
  2. The absorber control ECU reads the changes in each signal when performing the Test Mode check and outputs the DTC (C1787) if there is no change.

DTC No.
DTC Detection Condition
Trouble Area
C1787
There is no change in the absorber control switch signal when performing the Test Mode check.
  1. Absorber control switch
  2. Absorber control switch circuit
  3. Absorber control ECU

WIRING DIAGRAM


Lexus Gs430, Gs300. Uzs190 Grs190.Suspension Control.Adaptive Variable Suspension System. Dtc C1787 Ems Switch Circuit (Test Mode Dtc)


INSPECTION PROCEDURE

NOTICE:
When replacing the absorber control ECU, check the acceleration sensor assembly signal after replacement (Click here).
HINT:
  1. Check the condition of each related circuit connector before troubleshooting (Click here).
  2. When C1774 is output, inspect and repair the trouble areas indicated by C1774 first (Click here).
1.READ VALUE OF INTELLIGENT TESTER

  1. Connect the intelligent tester to DLC3.

  1. Turn the engine switch on (IG) and turn the intelligent tester main switch on.

  1. Select "Data List" mode on the intelligent tester (Click here).

    Data List: EMS
    Item
    		Measurement Item/
    Range (Display)
    		Normal Condition
    		Diagnostic Note
    Damping Force Switch 1
    		Damper force switch 1 (absorber control switch) /
    ON or OFF
    		The same as absorber control switch position
    		Operate the absorber control switch

  1. Operate the absorber control switch and check its operation in the Data List on the intelligent tester display.

    OK:
    The display on the intelligent tester changes according to the operation of the absorber control switch.


NG
Go to step 3
OK


2.RECONFIRM DTC

  1. Clear the DTC (Click here).

  1. Perform the Test Mode (Click here).

  1. Check if the same DTC is recorded (Click here).

    Result:

    Result
    		Proceed To
    DTC is output
    		A
    DTC is output (When troubleshooting accordance with the PROBLEM SYMPTOMS TABLE)
    		B
    DTC is not output
    		C


B
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

C
END
A

REPLACE ABSORBER CONTROL ECU

3.INSPECT ABSORBER CONTROL SWITCH


    Lexus Gs430, Gs300. Uzs190 Grs190.Suspension Control.Adaptive Variable Suspension System. Dtc C1787 Ems Switch Circuit (Test Mode Dtc)

  1. Remove the absorber control switch.

  1. Disconnect the absorber control switch connector.

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

    Resistance:
    Tester Connection
    		Switch Position
    		Specified Condition
    Switch terminal 4 -
    Switch terminal 3
    		NORM
    		10 kΩ or higher
    (No Continuity)
    Switch terminal 4 -
    Switch terminal 3
    		SPORT
    		Below 1 Ω
    (Continuity)


NG
REPLACE ABSORBER CONTROL SWITCH
OK


4.CHECK HARNESS AND CONNECTOR (ABSORBER CONTROL SWITCH TO ABSORBER CONTROL ECU, BODY GROUND)


    Lexus Gs430, Gs300. Uzs190 Grs190.Suspension Control.Adaptive Variable Suspension System. Dtc C1787 Ems Switch Circuit (Test Mode Dtc)

  1. Disconnect the absorber control ECU connector.

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

    Resistance:
    Tester Connection
    		Specified Condition
    L72-9 (SW1) - L41-4
    		Below 1 Ω
    L72-9 (SW1) - Body ground
    		10 kΩ or higher

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

    Resistance:
    Tester Connection
    		Specified Condition
    L41-3 - Body ground
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


5.RECONFIRM DTC

  1. Clear the DTC (Click here).

  1. Perform Test Mode (Click here).

  1. Check if the same DTC is recorded (Click here).

    HINT:
    Reinstall the sensor, connectors, etc. and restore the vehicle to its prior condition before rechecking for DTCs.

    Result:

    Result
    		Proceed To
    DTC is output
    		A
    DTC is output (When troubleshooting accordance with the PROBLEM SYMPTOMS TABLE)
    		B
    DTC is not output
    		C


B
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

C
END
A

REPLACE ABSORBER CONTROL ECU