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Home >> Lexus >> 2010 >> GS 350 AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 218 (Vehicle Stability Control (Diagnostic Codes & Symptom Tests)) >> Vehicle Stability Control System >> DTC C1426: Stop Light Switch OFF Stuck Malfunction >> Procedure

DTC C1426: Stop Light Switch OFF Stuck Malfunction: Procedure

WARNING: This page is about a different car, the 2009 Lexus IS 350 and 2009 Lexus IS 250. However, it is still accessible from the selected car via links, so may be relevant.
  1. 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

    NG → See step   4 

    OK: Go to next step 

  2. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Select the Data List on the Techstream. Refer to DATA LIST / ACTIVE TEST .
      DATA LIST

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Stop Light 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 beyond the specified point
      OFF: Brake pedal not depressed beyond the specified point      		 -
    4. Check that the stop light switch display and brake pedal load sensing switch display observed on the Techstream change according to brake pedal operation.

      OK

      The Techstream displays ON or OFF according to brake pedal operation.

    5. 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 (Turning on of the stop light switch is not confirmed) B
      NG (The brake pedal load sensing switch turns on first) C

    C → See step   16 

    B → See step   15 

    A: Go to next step 

  3. RECONFIRM DTC 
    1. Turn the engine switch off.
    2. Clear the DTCs. Refer to DTC CHECK / CLEAR .
    3. Start the engine.
    4. Depress the brake pedal several times to test the stop light circuit.
    5. Check if the same DTC is recorded. Refer to DTC CHECK / CLEAR .

      Result

      Result Proceed to
      DTC (C1426) is not output A
      DTC (C1426) is output B

      HINT: 

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step. Refer to PROBLEM SYMPTOMS TABLE .

    B → See step   19 

    A → See step   17 

  4. INSPECT STOP SW FUSE 
    1. Remove the STOP SW fuse from the main body ECU RH (cowl side junction block RH).
      Fig 1: Identifying STOP SW Fuse
      GTY144153Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. 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: Go to next step 

  5. INSPECT STOP LIGHT SWITCH (POWER SOURCE TERMINAL) 
    1. Install the STOP SW fuse.
      Fig 2: Identifying Connector Terminals
      GTY135023Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Make sure that there is no looseness at the locking part and the connecting part of the connectors.
    3. Disconnect the stop light switch connector.
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A22-2 - Body ground Always 11 to 14 V

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

    OK: Go to next step 

  6. INSPECT STOP LIGHT SWITCH 
    1. Measure the resistance according to the value(s) in the table below.
      Fig 3: Inspecting Stop Light Switch
      GTY139025Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

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

      Result

      Result Proceed to
      OK (for automatic transmission) A
      OK (for manual transmission) B
      NG C

    C → See step   21 

    B → See step   13 

    A: Go to next step 

  7. INSPECT STOP LIGHT CONTROL (BRK-LP) RELAY 
    1. Remove the stop light control (BRK-LP) relay.
      Fig 4: Identifying Stop Light Control Relay (BRK-LP) Terminals
      GTY137907Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 - 4 Voltage is not applied between terminals 1 and 2 Below 1 Ω

    NG → REPLACE STOP LIGHT CONTROL (BRK-LP) RELAY 

    OK: Go to next step 

  8. INSPECT STOP LIGHT CONTROL RELAY 
    1. Check the stop light control relay. Refer to INSPECTION .

      OK

      The stop light control relay is normal.

    NG → See step   22 

    OK: Go to next step 

  9. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - STOP LIGHT CONTROL RELAY) 
    1. Make sure that there is no looseness at the locking part and the connecting part of the connector.
      Fig 5: Identifying Connector Terminals
      GTY133447Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the stop light control relay connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A22-1 - J89-2 (STP) Always Below 1 Ω
      A22-1 - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  10. CHECK HARNESS AND CONNECTOR (STOP LIGHT CONTROL RELAY - ENGINE ROOM NO. 2 RELAY BLOCK) 
    1. Measure the resistance according to the value(s) in the table below.
      Fig 6: Identifying Connector Terminals & Relay Terminals
      GTY127080Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      J89-8 (OUT) - Stop light control (BRK-LP) relay terminal 4 Always Below 1 Ω
      J89-8 (OUT) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  11. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - ENGINE ROOM NO. 2 RELAY BLOCK) 
    1. Make sure that there is no looseness at the locking part and the connecting part of the connector.
      Fig 7: Identifying Connector Terminals & Relay Terminals
      GTY141317Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the skid control ECU connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A58-22 (STP2) - Stop light control (BRK-LP) relay terminal 3 Always Below 1 Ω

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  12. RECONFIRM DTC 
    1. Clear the DTCs. Refer to DTC CHECK / CLEAR .
    2. Start the engine.
    3. Depress the brake pedal several times to test the stop light circuit.
    4. Check if the same DTC is recorded. Refer to DTC CHECK / CLEAR .

      HINT: 

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

      Result

      Result Proceed to
      DTC (C1426) is not output A
      DTC (C1426) is output B

      HINT: 

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step. Refer to PROBLEM SYMPTOMS TABLE .

    B → See step   19 

    A → See step   18 

  13. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - STOP LIGHT SWITCH) 
    1. Make sure that there is no looseness at the locking part and the connecting part of the connector.
      Fig 8: Identifying Connector Terminals
      GTY141520Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the skid control ECU connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A58-2 (STP1) - A22-1 Always Below 1 Ω

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  14. RECONFIRM DTC 
    1. Reconnect the skid control ECU connector and the stop light switch connector.
    2. Clear the DTCs. Refer to DTC CHECK / CLEAR .
    3. Start the engine.
    4. Depress the brake pedal several times to test the stop light circuit.
    5. Check if the same DTC is recorded. Refer to DTC CHECK / CLEAR .

      Result

      Result Proceed to
      DTC (C1426) is not output A
      DTC (C1426) is output B

      HINT: 

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step. Refer to PROBLEM SYMPTOMS TABLE .

    B → See step   19 

    A → See step   18 

  15. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - STOP LIGHT SWITCH) 
    1. Turn the engine switch off.
      Fig 9: Identifying Connector Terminals
      GTY141520Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Make sure that there is no looseness at the locking part and the connecting part of the connectors.
    3. Disconnect the skid control ECU connector and the stop light switch connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A58-2 (STP1) - A22-1 Always Below 1 Ω

      HINT: 

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step. Refer to PROBLEM SYMPTOMS TABLE .

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   19 

  16. CHECK BRAKE PEDAL AND STOP LIGHT SWITCH INSTALLATION 
    1. Turn the engine switch off.
    2. Check the brake pedal height and stop light switch installation. Refer to ADJUSTMENT .

      OK

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

      HINT: 

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step. Refer to PROBLEM SYMPTOMS TABLE .

    NG → See step   23 

    OK → See step   20 

  17. CHECK FOR INTERMITTENT PROBLEMS. Refer to  ELECTRONIC CIRCUIT INSPECTION PROCEDURE 
  18. INSPECT LIGHTING SYSTEM (STOP LIGHT CIRCUIT). Refer to  PROBLEM SYMPTOMS TABLE 
  19. REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL 
  20. REPLACE BRAKE PEDAL SUPPORT ASSEMBLY (BRAKE PEDAL LOAD SENSING SWITCH). Refer to  REMOVAL 
  21. REPLACE STOP LIGHT SWITCH. Refer to  REMOVAL 
  22. REPLACE STOP LIGHT CONTROL RELAY. Refer to  REMOVAL 
  23. ADJUST BRAKE PEDAL OR STOP LIGHT SWITCH. Refer to  ADJUSTMENT 
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