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Home >> Lexus >> 2008 >> IS F >> Repair and Diagnosis >> Brakes >> Brakes Control Systems >> Brake Control / Dynamic Control Systems >> Vehicle Stability Control System >> DTC C1380/64 Stop Light Control Relay Malfunction >> Inspection Procedure
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Inspection Procedure

NOTE: When replacing the skid control ECU, perform zero point calibration and store system information (See CALIBRATION  ).

HINT:

When C1249/49 is output together with C1380/64, inspect and repair the trouble areas indicated by C1249/49 first (See DTC C1249/49 OPEN IN STOP LIGHT SWITCH CIRCUIT  ).

  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 

      BRAKE PEDAL REFERENCE

      Condition Illumination Condition
      Brake pedal depressed ON
      Brake pedal released OFF

    NG: INSPECT STOP LIGHT CIRCUIT  (See PROBLEM SYMPTOMS TABLE )

    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 mode on the Techstream (See DATA LIST / ACTIVE TEST  )

      ABS/VSC/TRAC 

      NORMAL CONDITION

      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      		 -
    4. Check that the stop light switch condition observed on the Techstream changes according to brake pedal operation

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

    NG: Go to step  9

    OK: Go to next step 

  3. INSPECT SKID CONTROL ECU (STP2 TERMINAL) 
    1. Turn the engine switch off
    2. Make sure that there is no looseness at the locking part and the connecting part of the connector.
    3. Disconnect the skid control ECU connector.
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage 

      STANDARD VOLTAGE

      Tester Connection Switch Condition Specified Condition
      A35-20 (STP2) - Body ground Stop light switch ON (Brake pedal depressed) 8 to 14 V
      A35-20 (STP2) - Body ground Stop light switch OFF (Brake pedal released) Below 1.5 V
      5. Fig 1: Identifying Skid Control ECU (STP2 Terminal)
      G05752640Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (STP2 CIRCUIT) 

    OK: Go to next step 

  4. PERFORM ACTIVE TEST USING TECHSTREAM (STOP LIGHT CONTROL (BRK-LP) RELAY) 
    1. Reconnect the skid control ECU connector.
    2. Connect the Techstream to the DLC3
    3. Turn the engine switch on (IG)
    4. Select the Active Test mode on the Techstream (See DATA LIST / ACTIVE TEST  )

      ABS/VSC/TRAC 

      CONTROL RANGE REFERENCE

      Tester Display Test Part Control Range Diagnostic Note
      Stop Light Relay Stop light control (BRK-LP) relay Relay ON/OFF Stop lights come on
    5. Check that the "ON" and "OFF" of the stop lights can be shown on the rear combination light by the Techstream.

      OK: The stop lights turn on or off in accordance with the Techstream. 

    NG: Go to step  6

    OK: Go to next step 

  5. RECONFIRM DTC 
    1. Turn the engine switch off
    2. Clear the DTCs (See DTC CHECK / CLEAR  )
    3. Turn the engine switch on (IG)
    4. Perform a road test
    5. Check if the same DTC is recorded (See DTC CHECK / CLEAR  )

      Result 

      RESULT REFERENCE

      Result Proceed to
      DTC (C1380/64) is not output A
      DTC (C1380/64) is output B

    B: REPLACE SKID CONTROL ECU  (See REMOVAL  )

    A: CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION)  (See DIAGNOSIS SYSTEM  )

  6. INSPECT STOP LIGHT CONTROL RELAY (BRK-LP) 
    1. Turn the engine switch off.
    2. Remove the stop light control (BRK-LP) relay
    3. Measure the resistance according to the value(s) in the table below

      Standard Resistance 

      STANDARD RESISTANCE

      Tester Connection Condition Specified Condition
      3 - 4 Voltage is not applied between terminals 1 and 2 Below 1 Ω
      3 - 5 Voltage is not applied between terminals 1 and 2 10 kΩ or higher
      3 - 4 Voltage is applied between terminals 1 and 2 10 kΩ or higher
      3 - 5 Voltage is applied between terminals 1 and 2 Below 1 Ω
      Fig 2: Identifying Stop Light Control Relay (BRK-LP)
      G05752627Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

    OK: Go to next step 

  7. INSPECT ENGINE ROOM NO. 3 RELAY BLOCK (POWER SOURCE TERMINAL) 
    1. Measure the voltage according to the value(s) in the table below.

      Standard Voltage 

      STANDARD VOLTAGE

      Tester Connection Condition Specified Condition
      Stop light control (BRK-LP) relay terminal 5 -Body ground Always 11 to 14 V
      Stop light control (BRK-LP) relay terminal 2 -Body ground Engine switch on (IG) 11 to 14 V
      2. Fig 3: Identifying Engine Room No. 3 Relay Block (Power Source Terminal)
      G05752642Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

    OK: Go to next step 

  8. INSPECT SKID CONTROL ECU (STPO TERMINAL) 
    1. Install the stop light control (BRK-LP) relay
    2. Make sure that there is no looseness at the locking part and the connecting part of the connector
    3. Disconnect the skid control ECU connector.
    4. Turn the engine switch on (IG)
    5. Measure the voltage according to the value(s) in the table below

      Standard Voltage 

      STANDARD VOLTAGE

      Tester Connection Switch Condition Specified Condition
      A35-21 (STPO) - Body ground Engine switch on (IG) 11 to 14 V
      6. Fig 4: Identifying Skid Control ECU (STPO Terminal)
      G05752643Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (STPO CIRCUIT) 

    OK: REPLACE SKID CONTROL ECU  (See REMOVAL  )

  9. INSPECT SKID CONTROL ECU (STP1 TERMINAL) 
    1. Turn the engine switch off.
    2. Make sure that there is no looseness at the locking part and the connecting part of the connector
    3. Disconnect the skid control ECU connector
    4. Measure the voltage according to the value(s) in the table below

      Standard Voltage 

      STANDARD VOLTAGE

      Tester Connection Switch Condition Specified Condition
      J77-10 (STP1) - Body ground Stop light switch ON (Brake pedal depressed) 8 to 14 V
      J77-10 (STP1) - Body ground Stop light switch OFF (Brake pedal released) Below 1.5 V
      5. Fig 5: Identifying Skid Control ECU (STP1 Terminal)
      G05752616Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (STP1 CIRCUIT) 

    OK: REPLACE SKID CONTROL ECU  (See REMOVAL  )

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