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Home >> Toyota >> 2020 >> Avalon Limited >> Repair and Diagnosis >> Brakes >> Anti-Lock Brakes >> Electronically Controlled Brake System - Diagnostic Codes (C1336-P0571) (Except Hybrid) >> ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for Gasoline Model) >> DTC C1426: Stop Switch OFF Stuck [04/2018 - 08/2021] >> Procedure

DTC C1426: Stop Switch OFF Stuck [04/2018 - 08/2021]: Procedure

  1. READ VALUE USING TECHSTREAM (BS1 VOLTAGE VALUE) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Enter the following menus: Chassis / ABS/VSC/TRAC/EPB / Data List.

      Chassis > ABS/VSC/TRAC/EPB > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      BS1 Voltage Value +BS voltage value Min.: 0.00 V, Max.: 20.00 V - Changes in proportion to battery voltage

      Chassis > ABS/VSC/TRAC/EPB > Data List 

      Tester Display
      BS1 Voltage Value
    4. Take a note of the +BS voltage value.

      HINT: 

      The noted +BS voltage value is used in a later step.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  2

  2. CHECK BRAKE PEDAL AND STOP LIGHT SWITCH ASSEMBLY INSTALLATION 
    1. Check the brake pedal height installation.

      Refer to PROCEDURE - Step 1 [04/2018 - 08/2020] , or refer to PROCEDURE - Step 1 [08/2020 - 08/2021]

    2. Check the stop light switch assembly installation.

      Refer to INSTALLATION [04/2018 -]

      OK

      The brake pedal height and stop light switch assembly installation are normal.

      HINT: 

      If the on/off status of the stop light switch assembly and pressure increase information from the master cylinder pressure sensor do not match due to an improperly installed brake pedal or stop light switch assembly, this DTC may be stored. Therefore, be sure to check the installation condition of the pedal and switch before inspecting the input signals and other related parts.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    ADJUST BRAKE PEDAL OR STOP LIGHT SWITCH ASSEMBLY. Refer to  ADJUSTMENT [04/2018 - 08/2020]  , or refer to  ADJUSTMENT [08/2020 - 08/2021] 

    Result: 

    OK 

    See step  3

  3. CHECK STOP LIGHT OPERATION 
    1. Check that the stop lights come on when the brake pedal is depressed, and go off when the brake pedal is released.

      OK

      Condition Illumination Condition
      Brake pedal depressed On
      Brake pedal released Off

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  9

    Result: 

    OK 

    See step  4

  4. INSPECT STOP LIGHT SWITCH ASSEMBLY 
    1. Inspect the stop light switch assembly.

      Refer to ON-VEHICLE INSPECTION [04/2018 -]

      OK

      The stop light switch assembly is normal.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE STOP LIGHT SWITCH ASSEMBLY. Refer to  REMOVAL [04/2018 -] 

    Result: 

    OK 

    See step  5

  5. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH ASSEMBLY) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Enter the following menus: Chassis / ABS/VSC/TRAC/EPB / Data List.

      Chassis > ABS/VSC/TRAC/EPB > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Stop Light SW Stop light switch assembly ON or OFF ON: Brake pedal depressed
      OFF: Brake pedal released      		 -

      Chassis > ABS/VSC/TRAC/EPB > Data List 

      Tester Display
      Stop Light SW
    4. Check that the stop light switch assembly display observed on the Techstream changes according to brake pedal operation.

      OK

      The Techstream displays on or off according to brake pedal operation.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  6

  6. RECONFIRM DTC 
    1. Clear the DTCs.

      Chassis > ABS/VSC/TRAC/EPB > Clear DTCs 

    2. Turn the engine switch off.
    3. Start the engine.
    4. Drive the vehicle at a speed of 3 km/h (2 mph) or more and depress the brake pedal several times to test the stop light circuit.
    5. Check if the same DTC is output.

      Chassis > ABS/VSC/TRAC/EPB > Trouble Codes 

      Result

      Result Proceed to
      C1426 is not output A
      C1426 is output B

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [04/2018 -] 

    Result: 

    B 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [04/2018 - 08/2020]  , or refer to  REMOVAL [08/2020 - 08/2021] 

  7. CHECK HARNESS AND CONNECTOR (STP TERMINAL) 
    1. Turn the engine switch off.
      GTY908221Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Skid Control ECU (Brake Actuator Assembly))
    2. Make sure that there is no looseness at the locking part and the connecting part of the connector.

      OK

      The connector is securely connected.

    3. Disconnect the A28 skid control ECU (brake actuator assembly) connector.
    4. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

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

      Standard Voltage

      Tester Connection Condition Specified Condition
      A28-42 (STP) - Body ground Stop light switch assembly on (Brake pedal depressed) (+BS x 0.85) to 14 V*

      HINT: 

      *: The minimum voltage value varies depending on the +BS terminal voltage value. The minimum voltage is 85% or more of the +BS terminal voltage.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT) 

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL) 
    1. Measure the resistance according to the value(s) in the table below.
      GTY908217Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Skid Control ECU (Brake Actuator Assembly))

      Standard Resistance

      Tester Connection Condition Specified Condition
      A28-46 (GND1) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [04/2018 - 08/2020]  , or refer to  REMOVAL [08/2020 - 08/2021] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT) 

  9. INSPECT STOP LIGHT SWITCH ASSEMBLY 
    1. Inspect the stop light switch assembly.

      Refer to ON-VEHICLE INSPECTION [04/2018 -]

      OK

      The stop light switch assembly is normal.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE STOP LIGHT SWITCH ASSEMBLY. Refer to  REMOVAL [04/2018 -] 

    Result: 

    OK 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (STP TERMINAL) 
    1. Make sure that there is no looseness at the locking part and the connecting part of the connector.
      GTY908221Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Skid Control ECU (Brake Actuator Assembly))

      OK

      The connector is securely connected.

    2. Disconnect the A28 skid control ECU (brake actuator assembly) connector.
    3. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

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

      Standard Voltage

      Tester Connection Condition Specified Condition
      A28-42 (STP) - Body ground Stop light switch assembly on (Brake pedal depressed) (+BS x 0.85) to 14 V*
      A28-42 (STP) - Body ground Stop light switch assembly off (Brake pedal released) Below 1.5 V

      HINT: 

      *: The minimum voltage value varies depending on the +BS terminal voltage value. The minimum voltage is 85% or more of the +BS terminal voltage.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT) 

    Result: 

    OK 

    See step  11

  11. RECONFIRM DTC 
    1. Reconnect the A28 skid control ECU (brake actuator assembly) connector.
    2. Clear the DTCs.

      Chassis > ABS/VSC/TRAC/EPB > Clear DTCs 

    3. Turn the engine switch off.
    4. Start the engine.
    5. Drive the vehicle at a speed of 3 km/h (2 mph) or more and depress the brake pedal several times to test the stop light circuit.
    6. Check if the same DTC is output.

      Chassis > ABS/VSC/TRAC/EPB > Trouble Codes 

      Result

      Result Proceed to
      C1426 is not output A
      C1426 is output B

      HINT: 

      If the lighting system is normal but the DTC is still output, replace the skid control ECU (brake actuator assembly).

      Refer to REMOVAL [04/2018 - 08/2020] , or refer to REMOVAL [08/2020 - 08/2021]

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [04/2018 -] 

    Result: 

    B 

    INSPECT LIGHTING SYSTEM (STOP LIGHT CIRCUIT) 

    for Gasoline Model with Cornering Light: Refer to HOW TO PROCEED WITH TROUBLESHOOTING [04/2018 - 08/2021]

    for Gasoline Model without Cornering Light: Refer to HOW TO PROCEED WITH TROUBLESHOOTING [04/2018 - 08/2021]

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