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Home >> Lexus >> 2020 >> LC 500 >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> Electronically Controlled Brake System - Diagnostic Codes (Coupe) (2 Of 4) >> Electronically Controlled Brake System >> DTC C1311/11: Open in Main Relay 1 Circuit; DTC C1312/12: Short in Main Relay 1 Circuit; DTC C1313/13: Open in Main Relay 2 Circuit; DTC C1314/14: Short in Main Relay 2 Circuit [03/2017 - 09/2018] >> Procedure

DTC C1311/11: Open in Main Relay 1 Circuit; DTC C1312/12: Short in Main Relay 1 Circuit; DTC C1313/13: Open in Main Relay 2 Circuit; DTC C1314/14: Short in Main Relay 2 Circuit [03/2017 - 09/2018]: Procedure

  1. PERFORM ACTIVE TEST USING TECHSTREAM (ABS MAIN RELAY) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Select the Active Test on the Techstream.

      Refer to DATA LIST / ACTIVE TEST [03/2017 - 05/2023]

      Chassis > ABS/VSC/TRAC > Active Test 

      Tester Display Measurement Item Control Range Diagnostic Note
      ECB Main Relay ABS main relay 1 Relay ON/OFF ECB: Electronically Controlled Brake System
      ECB Main Relay2 ABS main relay 2 Relay ON/OFF ECB: Electronically Controlled Brake System

      Chassis > ABS/VSC/TRAC > Active Test 

      Tester Display
      ECB Main Relay

      ECB: Electronically Controlled Brake System

      Chassis > ABS/VSC/TRAC > Active Test 

      Tester Display
      ECB Main Relay2

      ECB: Electronically Controlled Brake System

    4. Select the Data List on the Techstream.

      Refer to DATA LIST / ACTIVE TEST [03/2017 - 05/2023]

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      ECB Main Relay ABS main relay 1 ON or OFF ON: Relay on
      OFF: Relay off      		 ECB: Electronically Controlled Brake System
      ECB Main Relay2 ABS main relay 2 ON or OFF ON: Relay on
      OFF: Relay off      		 ECB: Electronically Controlled Brake System

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display
      ECB Main Relay
      ECB Main Relay2

      ECB: Electronically Controlled Brake System

    5. Check that the condition of the ABS main relay observed on the Techstream changes according to Techstream operation.

      Result

      Result Proceed to
      ABS main relay in the Data List turns ON/OFF using the Active Test. A
      ABS main relay in the Data List does not change using the Active Test. B

    Result: 

    B 

    See step  4

    Result: 

    A 

    See step  2

  2. INSPECT SKID CONTROL ECU ASSEMBLY (SOLENOID POWER SUPPLY OUTPUT TERMINAL) 
    1. Measure the voltage according to the value(s) in the table below.
      GTY788353Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Skid Control ECU Assembly)

      Standard Voltage

      Tester Connection Condition Specified Condition
      A8-3 (BS01) - Body ground Approximately 1.5 seconds after turning engine switch on (IG) 8.8 to 14 V
      A11-7 (BS02) - Body ground Approximately 1.5 seconds after turning engine switch on (IG) 8.8 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (SOLENOID POWER SUPPLY OUTPUT CIRCUIT) 

    Result: 

    OK 

    See step  3

  3. RECONFIRM DTC 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [03/2017 - 09/2018]

      Chassis > ABS/VSC/TRAC > Clear DTCs 

    2. Turn the engine switch off.
    3. Turn the engine switch on (IG).
    4. Check if the same DTC is output.

      Refer to DTC CHECK / CLEAR [03/2017 - 09/2018]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      Result

      Result Proceed to
      DTCs C1311/11, C1312/12, C1313/13 and C1314/14 are not output. A
      DTCs C1311/11, C1312/12, C1313/13 and/or C1314/14 are output. B

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [03/2017 - 04/2020] 

    Result: 

    B 

    REPLACE SKID CONTROL ECU ASSEMBLY. Refer to  REMOVAL [03/2017 - 05/2023] 

  4. CHECK HARNESS AND CONNECTOR (+BI TERMINAL) 
    1. Make sure that there is no looseness at the locking part and the connecting part of the connectors.
      GTY785088Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Skid Control ECU Assembly)
    2. Disconnect the A9 and A11 skid control ECU assembly connectors.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A9-4 (+BI1) - Body ground Always 11 to 14 V
      A11-5 (+BI2) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (+BI CIRCUIT) 

    Result: 

    OK 

    See step  5

  5. INSPECT SKID CONTROL ECU ASSEMBLY (SOLENOID POWER SUPPLY OUTPUT TERMINAL) 
    1. Reconnect the A8 and A11 skid control ECU assembly connectors.
      GTY788353Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Skid Control ECU Assembly)
    2. Turn the engine switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A8-3 (BS01) - Body ground Approximately 1.5 seconds after turning engine switch on (IG) 8.8 to 14 V
      A11-7 (BS02) - Body ground Approximately 1.5 seconds after turning engine switch on (IG) 8.8 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE SKID CONTROL ECU ASSEMBLY. Refer to  REMOVAL [03/2017 - 05/2023] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (SOLENOID POWER SUPPLY OUTPUT CIRCUIT) 

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