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DTC C1A4B: Stop Light Relay Circuit [09/2015 - 08/2019]: Procedure

  1. INSPECT ENGINE START 
    1. Depress the brake pedal, push the engine switch and check that the engine starts.

      OK

      The engine starts.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO SFI SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2015 - ] 

    Result: 

    OK 

    See step  2

  2. 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 

    Result: 

    OK 

    See step  3

  3. INSPECT SEMICONDUCTOR POWER INTEGRATION ECU 
    1. Turn the engine switch off.
    2. Inspect the semiconductor power integration ECU.

      Refer to ON-VEHICLE INSPECTION [09/2015 - ]

      OK

      The semiconductor power integration ECU is normal.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  9

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (STPO TERMINAL VOLTAGE) 
    1. Turn the engine switch off.
    2. Disconnect the A41 skid control ECU (brake actuator assembly) connector.
      GTY618870Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Skid control ECU (brake actuator assembly))
    3. Measure the voltage according to the value (s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A41-32 (STPO) - Body ground Always 11 to 14 V
    4. Connect the A41 skid control ECU (brake actuator assembly) connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  14

    Result: 

    OK 

    See step  5

  5. 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 [09/2015 - 08/2019]

      Chassis > ABS/VSC/TRAC/EPB > Active Test 

      Tester Display Measurement Item Control Range Diagnostic Note
      Stop Light Relay Stop lights ON / OFF Test possible at vehicle speed of 0 km/h (0 mph)

      Chassis > ABS/VSC/TRAC/EPB > Active Test 

      Active Test Display
      Stop Light Relay
      Data List Display
      Stop Light Relay Output
    2. According to the display on the Techstream, perform the Data List Stop Light Relay.

      Refer to DATA LIST / ACTIVE TEST [09/2015 - 08/2019]

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

      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  11

    Result: 

    A 

    See step  6

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

      Refer to DATA LIST / ACTIVE TEST [09/2015 - 08/2019]

      Chassis > ABS/VSC/TRAC/EPB > Active Test 

      Tester Display Measurement Item Control Range Diagnostic Note
      Stop Light Relay Stop lights ON / OFF Test possible at vehicle speed of 0 km/h (0 mph)

      Chassis > ABS/VSC/TRAC/EPB > Active Test 

      Tester Display
      Stop Light Relay
    2. Measure the voltage according to the value (s) in the table below.

      HINT: 

      Do not disconnect the semiconductor power integration ECU connector.

      Standard Voltage

      Tester Connection Condition Specified Condition
      1D-3 (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  10

    Result: 

    OK 

    See step  7

  7. REPLACE SEMICONDUCTOR POWER INTEGRATION ECU 
    1. Replace the semiconductor power integration ECU.

      Refer to COMPONENTS [09/2015 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

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

      Refer to DTC CHECK / CLEAR [09/2015 - 08/2019]

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

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

      Refer to DATA LIST / ACTIVE TEST [09/2015 - 08/2019]

      Chassis > ABS/VSC/TRAC/EPB > Active Test 

      Tester Display Measurement Item Control Range Diagnostic Note
      Stop Light Relay Stop lights ON / OFF Test possible at vehicle speed of 0 km/h (0 mph)

      Chassis > ABS/VSC/TRAC/EPB > Active Test 

      Tester Display
      Stop Light Relay
    3. Check for DTCs.

      Refer to DTC CHECK / CLEAR [09/2015 - 08/2019]

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

      Result

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

    Result: 

    A 

    END 

    Result: 

    B 

    GO TO DTC CHART (C1380). Refer to  DTC C1380: Stop Light Control Relay Malfunction [09/2015 - 08/2019] 

  9. REPLACE SEMICONDUCTOR POWER INTEGRATION ECU 
    1. Replace the semiconductor power integration ECU.

      Refer to COMPONENTS [09/2015 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

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

      Refer to COMPONENTS [09/2015 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

  11. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU - SKID CONTROL ECU) 
    1. Turn the engine switch off.
    2. Remove the semiconductor power integration ECU.
    3. Disconnect the A41 skid control ECU (brake actuator assembly) connector.
      GTY618872Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Skid control ECU (brake actuator assembly))
    4. Measure the resistance according to the value (s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      1F-9 (OUT) - A41-37 (STP2) Always Below 1 Ω
    5. Connect the A41 skid control ECU (brake actuator assembly) connector.
    6. Install the semiconductor power integration ECU.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  13

    Result: 

    OK 

    See step  12

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

      Refer to COMPONENTS [09/2015 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

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

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

  14. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU - SKID CONTROL ECU) 
    1. Turn the engine switch off.
    2. Remove the semiconductor power integration ECU.
    3. Disconnect the A41 skid control ECU (brake actuator assembly) connector.
    4. Measure the resistance according to the value (s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      1D-3 (ACC) - A41-32 (STPO) Always Below 1 Ω
      1D-3 (ACC) or A41-32 (STPO) - Body ground Always 10 kΩ or higher
    5. Connect the A41 skid control ECU (brake actuator assembly) connector.
    6. Install the semiconductor power integration ECU.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  16

    Result: 

    OK 

    See step  15

  15. REPLACE SEMICONDUCTOR POWER INTEGRATION ECU 
    1. Replace the semiconductor power integration ECU.

      Refer to COMPONENTS [09/2015 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

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

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

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