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DTC C1A4B: Stop Light Relay Circuit [10/2015 - 09/2017]: Procedure

  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

      The stop lights illuminate when the brake pedal is depressed. The stop lights turn off when the brake pedal is released.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO LIGHTING SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2015 - ] 

    Result: 

    OK 

    See step  2

  2. INSPECT NO. 2 INTEGRATION RELAY 
    1. Turn the engine switch off.
    2. Inspect the No. 2 integration relay.

      Refer to ON-VEHICLE INSPECTION [09/2014 - ]

      OK

      The No. 2 integration relay is normal.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  8

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (STPO TERMINAL VOLTAGE) 
    1. Turn the engine switch off.
    2. Disconnect the brake actuator assembly (skid control ECU) connector.
      GTY669347Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Brake Actuator Assembly [Skid Control ECU])
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A77-26 (STPO) - Body ground Always 11 to 14 V
    4. Connect the brake actuator assembly (skid control ECU) connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  13

    Result: 

    OK 

    See step  4

  4. PERFORM ACTIVE TEST USING TECHSTREAM (STOP LIGHT RELAY OUTPUT) 
    1. According to the display on the Techstream, perform the Active Test Stop Light Relay.

      Refer to DATA LIST / ACTIVE TEST [10/2015 - ]

      ABS/VSC/TRAC

      Tester Display Test Part Control Range Diagnostic Note
      Stop Light Relay Stop lights ON / OFF Test possible at vehicle speed of 0 km/h (0 mph)
    2. According to the display on the Techstream, perform the Data List Stop Light Relay.

      Refer to DATA LIST / ACTIVE TEST [10/2015 - ]

      ABS/VSC/TRAC

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Stop Light Relay Output STPO terminal output condition / ON or OFF ON: Output
      OFF: Not output      		 -
    3. Check that the Data List item Stop Light Relay Output changes between ON and OFF and the stop lights turn on and off according to the operation of the Active Test.

      Result

      Result Proceed to
      The Data List item Stop Light Relay Output does not change between ON and OFF and the stop lights do not turn ON and OFF according to the operation of the Active Test. A
      The Data List item Stop Light Relay Output changes between ON and OFF but the stop lights do not turn ON and OFF according to the operation of the Active Test. B

    Result: 

    B 

    See step  10

    Result: 

    A 

    See step  5

  5. INSPECT BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) 
    1. According to the display on the Techstream, perform the Active Test Stop Light Relay.

      Refer to DATA LIST / ACTIVE TEST [10/2015 - ]

      ABS/VSC/TRAC

      Tester Display Test Part Control Range Diagnostic Note
      Stop Light Relay Stop lights ON / OFF Test possible at vehicle speed of 0 km/h (0 mph)
    2. Measure the voltage according to the value(s) in the table below.

      HINT: 

      Do not disconnect the No. 2 integration relay connector.

      Standard Voltage

      Tester Connection Condition Specified Condition
      2A-7 (ACC) - Body ground Engine switch on (IG)
      (Active test OFF)      		 11 to 14 V
      Engine switch on (IG)
      (Active test ON)      		 Below 1.5 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  9

    Result: 

    OK 

    See step  6

  6. REPLACE NO. 2 INTEGRATION RELAY 
    1. Replace the No. 2 integration relay.

      Refer to REMOVAL [09/2014 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  7

  7. CHECK DTC OUTPUT (VEHICLE STABILITY CONTROL SYSTEM) 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [10/2015 - ]

    2. According to the display on the Techstream, perform the Active Test Stop Light Relay.

      Refer to DATA LIST / ACTIVE TEST [10/2015 - ]

      ABS/VSC/TRAC

      Tester Display Test Part Control Range Diagnostic Note
      Stop Light Relay Stop lights ON / OFF Test possible at vehicle speed of 0 km/h (0 mph)
    3. Check for DTCs.

      Refer to DTC CHECK / CLEAR [10/2015 - ]

      Result

      Result Proceed to
      DTC C1380 is not output A
      DTC C1380 is output B

    Result: 

    A 

    END (NO. 2 INTEGRATION RELAY WAS DEFECTIVE) 

    Result: 

    B 

    GO TO DTC CHART (C1380). Refer to  DTC C1380: Stop Light Control Relay Malfunction [10/2015 - 09/2017] 

  8. REPLACE NO. 2 INTEGRATION RELAY 
    1. Replace the No. 2 integration relay.

      Refer to REMOVAL [09/2014 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  7

  9. REPLACE BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) 
    1. Replace the brake actuator assembly (skid control ECU).

      Refer to REMOVAL [10/2015 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  7

  10. CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY - BRAKE ACTUATOR ASSEMBLY [SKID CONTROL ECU]) 
    1. Turn the engine switch off.
    2. Remove the No. 2 integration relay.
    3. Disconnect the A77 brake actuator assembly (skid control ECU) connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      2A-3 (STOP) - A77-5 (STP2) Always Below 1 Ω
    5. Connect the A77 brake actuator assembly (skid control ECU) connector.
    6. Install the No. 2 integration relay.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  12

    Result: 

    OK 

    See step  11

  11. REPLACE BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) 
    1. Replace the brake actuator assembly (skid control ECU).

      Refer to REMOVAL [10/2015 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  7

  12. REPAIR OR REPLACE HARNESS OR CONNECTOR 
    1. Repair or replace the harness or connector.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  7

  13. CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY - BRAKE ACTUATOR ASSEMBLY [SKID CONTROL ECU]) 
    1. Turn the engine switch off.
    2. Remove the No. 2 integration relay.
    3. Disconnect the A77 brake actuator assembly (skid control ECU) connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      2A-7 (ACC) - A77-26 (STPO) Always Below 1 Ω
      2A-7 (ACC) or A77-26 (STPO) - Body ground Always 10 kΩ or higher
    5. Connect the A77 brake actuator assembly (skid control ECU) connector.
    6. Install the No. 2 integration relay.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  15

    Result: 

    OK 

    See step  14

  14. REPLACE NO. 2 INTEGRATION RELAY 
    1. Replace the No. 2 integration relay.

      Refer to REMOVAL [09/2014 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  7

  15. REPAIR OR REPLACE HARNESS OR CONNECTOR 
    1. Repair or replace the harness or connector.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  7

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