Dtc C1249/49 Open In Stop Light Switch Circuit

Brake. Lexus Is250, Is220D. Gse20 Ale20
Brake Control. Lexus Is250, Is220D. Gse20 Ale20

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT STOP SW FUSE

CHECK STOP LIGHT OPERATION

INSPECT SKID CONTROL ECU (STP TERMINAL)

INSPECT SKID CONTROL ECU (IG1 AND GND TERMINAL)

READ VALUE OF INTELLIGENT TESTER (STOP LIGHT SWITCH AND BRAKE PEDAL LOAD SENSING SWITCH)

RECONFIRM DTC

CHECK BRAKE PEDAL AND STOP LIGHT SWITCH INSTALLATION

RECONFIRM DTC

INSPECT STOP LIGHT SWITCH (POWER SOURCE TERMINAL)

INSPECT STOP LIGHT SWITCH

CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - STOP LIGHT SWITCH)

RECONFIRM DTC

DTC C1249/49 Open in Stop Light Switch Circuit


DESCRIPTION

The skid control ECU inputs the stop light switch signal and the condition of brake operation.
The skid control ECU has an open detection circuit, which outputs this DTC when detecting an open in the stop light input line while the stop light switch is OFF.

DTC No.
DTC Detection Condition
Trouble Area
C1249/49
  1. When IG1 terminal voltage is 9.5 to 17.2 V, an open circuit of the stop light switch continues for 0.3 seconds or more.
  2. When the brake pedal load sensing switch is ON, the master cylinder pressure is 2 Mpa or more and the deceleration calculated from the vehicle speed is 0.2 G or more, the stop light switch is OFF for 2 seconds or more.
  1. STOP SW fuse
  2. Stop light switch
  3. Stop light switch circuit
  4. Skid control ECU

WIRING DIAGRAM


Lexus Is250, Is220D. Gse20 Ale20.Brake Control.Vehicle Stability Control System (W/ Vdim). Dtc C1249/49 Open In Stop Light Switch Circuit


Lexus Is250, Is220D. Gse20 Ale20.Brake Control.Vehicle Stability Control System (W/ Vdim). Dtc C1249/49 Open In Stop Light Switch Circuit


INSPECTION PROCEDURE

NOTICE:
When replacing the skid control ECU, perform zero point calibration and store system information (Click here).
1.INSPECT STOP SW FUSE


    Lexus Is250, Is220D. Gse20 Ale20.Brake Control.Vehicle Stability Control System (W/ Vdim). Dtc C1249/49 Open In Stop Light Switch Circuit

  1. Remove the STOP SW fuse from the main body ECU RH.

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

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    STOP SW (7.5 A) fuse
    		Always
    		Below 1 Ω


NG
REPLACE STOP SW FUSE
OK


2.CHECK STOP LIGHT OPERATION

  1. Install the STOP SW fuse.

  1. Check that the stop light comes on when the brake pedal is depressed, and goes off when the brake pedal is released.

    OK:

    Condition
    		Illumination Condition
    Brake pedal depressed
    		ON
    Brake pedal released
    		OFF


NG
Go to step 9
OK


3.INSPECT SKID CONTROL ECU (STP TERMINAL)


    Lexus Is250, Is220D. Gse20 Ale20.Brake Control.Vehicle Stability Control System (W/ Vdim). Dtc C1249/49 Open In Stop Light Switch Circuit

  1. Disconnect the skid control ECU connector.

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

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    J77-10 (STP) - Body ground
    		Stop light switch ON (Brake pedal depressed)
    		8 to 14 V
    J77-10 (STP) - Body ground
    		Stop light switch OFF (Brake pedal released)
    		Below 1.5 V


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)
OK


4.INSPECT SKID CONTROL ECU (IG1 AND GND TERMINAL)


    Lexus Is250, Is220D. Gse20 Ale20.Brake Control.Vehicle Stability Control System (W/ Vdim). Dtc C1249/49 Open In Stop Light Switch Circuit

  1. Disconnect the skid control ECU connectors.

  1. Turn the engine switch on (IG).

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

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    J77-1 (IG1) - Body ground
    		Engine switch on (IG)
    		10 to 14 V

  1. Turn the engine switch off.

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

    Standard resistance:
    LHD:
    Tester Connection
    		Condition
    		Specified Condition
    J78-26 (GND1) - Body ground
    		Always
    		Below 1 Ω
    J78-14 (GND2) - Body ground
    		Always
    		Below 1 Ω
    A35-22 (GND3) - Body ground
    		Always
    		Below 1 Ω
    RHD:
    Tester Connection
    		Condition
    		Specified Condition
    J78-26 (GND1) - Body ground
    		Always
    		Below 1 Ω
    J78-14 (GND2) - Body ground
    		Always
    		Below 1 Ω
    J98-22 (GND3) - Body ground
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 OR GND CIRCUIT)
OK


5.READ VALUE OF INTELLIGENT TESTER (STOP LIGHT SWITCH AND BRAKE PEDAL LOAD SENSING SWITCH)

  1. Reconnect the skid control ECU connectors.

  1. Connect the intelligent tester to the DLC3.

  1. Start the engine.

  1. Select the Data List mode on the intelligent tester.

    ABS / VSC:
    Item (Display)
    		Measurement Item / Range (Display)
    		Normal Condition
    Stop Lamp SW
    		Stop light switch / ON or OFF
    		ON: Brake pedal depressed
    OFF: Brake pedal released
    Brake Pedal Load Sensing SW
    		Brake pedal load sensing switch / ON or OFF
    		ON: Brake pedal depressed
    OFF: Brake pedal released

  1. Check that the stop light display observed on the intelligent tester changes when the brake pedal is depressed.

    OK:
    When the brake pedal is depressed, the intelligent tester displays "ON".

  1. Slowly depress the brake pedal, and check when the stop light switch and brake pedal load sensing switch turn ON.

    OK:
    First the stop light switch should turn ON, and then the brake pedal load sensing switch should turn ON.

    Result:

    Result
    		Proceed to
    OK
    		A
    NG (The turning on of the stop light switch is not confirmed)
    		B
    NG (The brake pedal load sensing switch turns on first)
    		C


B
REPLACE SKID CONTROL ECU

C
Go to step 7
A


6.RECONFIRM DTC

  1. Clear the DTC (Click here).

  1. Start the engine.

  1. Depress the brake pedal several times to test the stop light circuit.

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

    Result:

    Condition
    		Proceed to
    DTC (C1249/49) is not output
    		A
    DTC (C1249/49) is output
    		B
    HINT:
    If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step (Click here).


B
REPLACE SKID CONTROL ECU
A

USE SIMULATION METHOD TO CHECK

7.CHECK BRAKE PEDAL AND STOP LIGHT SWITCH INSTALLATION

  1. Check the brake pedal height and stop light switch installation (Click here).

    OK:
    The brake pedal and stop light switch are normal.


NG
ADJUST BRAKE PEDAL OR STOP LIGHT SWITCH
OK


8.RECONFIRM DTC

  1. Clear the DTC (Click here).

  1. Start the engine.

  1. Depress the brake pedal several times to test the stop light circuit.

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

    Result:

    Condition
    		Proceed to
    DTC (C1249/49) is not output
    		A
    DTC (C1249/49) is output
    		B
    HINT:
    If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step (Click here).


B
REPLACE BRAKE PEDAL SUB-ASSEMBLY (BRAKE PEDAL LOAD SENSING SWITCH)
A

USE SIMULATION METHOD TO CHECK

9.INSPECT STOP LIGHT SWITCH (POWER SOURCE TERMINAL)


    Lexus Is250, Is220D. Gse20 Ale20.Brake Control.Vehicle Stability Control System (W/ Vdim). Dtc C1249/49 Open In Stop Light Switch Circuit

  1. Disconnect the stop light switch connector.

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

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A22-2 - Body ground
    		Always
    		10 to 14 V


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)
OK


10.INSPECT STOP LIGHT SWITCH


    Lexus Is250, Is220D. Gse20 Ale20.Brake Control.Vehicle Stability Control System (W/ Vdim). Dtc C1249/49 Open In Stop Light Switch Circuit

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

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    1 - 2
    		Switch pin free
    		Below 1 Ω
    1 - 2
    		Switch pin pushed in
    		10 kΩ or higher


NG
REPLACE STOP LIGHT SWITCH
OK


11.CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - STOP LIGHT SWITCH)


    Lexus Is250, Is220D. Gse20 Ale20.Brake Control.Vehicle Stability Control System (W/ Vdim). Dtc C1249/49 Open In Stop Light Switch Circuit

  1. Disconnect the skid control ECU connector.

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

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    J77-10 (STP) - A22-1
    		Always
    		Below 1 Ω
    J77-10 (STP) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


12.RECONFIRM DTC

  1. Reconnect the skid control ECU connector and the stop light switch connector.

  1. Clear the DTC (Click here).

  1. Start the engine.

  1. Depress the brake pedal several times to test the stop light circuit.

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

    Result:

    Condition
    		Proceed to
    DTC (C1249/49) is not output
    		A
    DTC (C1249/49) is output
    		B
    HINT:
    If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step (Click here).


B
REPLACE SKID CONTROL ECU
A

INSPECT LIGHTING SYSTEM (STOP LIGHT CIRCUIT)