LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2013 >> CT 200h Base >> Repair and Diagnosis (Single Page) >> Brakes >> Traction Control >> Electronically Controlled Brake System (Diagnostic Codes & Symptom Tests) >> Electronically Controlled Brake System >> DTC C1311/11: Open in Main Relay 1 Circuit; DTC C1312/12: Short in Main Relay 1 Circuit >> Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC C1311/11: Open in Main Relay 1 Circuit; DTC C1312/12: Short in Main Relay 1 Circuit: Procedure

  1. PERFORM ACTIVE TEST USING TECHSTREAM (ABS MAIN RELAY) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Select the Active Test on the Techstream. Refer to DATA LIST / ACTIVE TEST [08/2012 - ] .
      ABS/VSC/TRAC

      Tester Display Test Part Control Range Diagnostic Note
      ECB* Main Relay ABS main relay Relay ON/OFF -

      *: Electronically Controlled Brake System

    4. Select the Data List on the Techstream. Refer to DATA LIST / ACTIVE TEST [08/2012 - ] .
      ABS/VSC/TRAC

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      ECB* Main Relay ABS main relay / ON or OFF ON: Relay on
      OFF: Relay off
      -

      *: Electronically Controlled Brake System

    5. Check the operating condition of the ABS main relay when operating it with the Techstream.

      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

    B → See step   4 

    A: Go to next step 

  2. INSPECT SKID CONTROL ECU (BS TERMINAL) 
    1. Turn the power switch off.
      Fig 1: Identifying A61 Connector Terminals
      GTY349137Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    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

      Tester Connection Condition Specified Condition
      A61-15 (BS) - Body ground Always 11 to 14 V
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to Skid Control ECU)

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (BS CIRCUIT) 

    OK: Go to next step 

  3. RECONFIRM DTC 
    1. Reconnect the skid control ECU connector.
    2. Clear the DTCs. Refer to DTC CHECK / CLEAR [08/2012 - ] .
    3. Turn the power switch on (IG).
    4. Check if the same DTC is recorded. Refer to DTC CHECK / CLEAR [08/2012 - ] .

      Result

      Result Proceed to
      DTCs (C1311/11and C1312/12) are not output A
      DTCs (C1311/11 and/or C1312/12) are output B

    B → See step   6 

    A → See step   7 

  4. INSPECT SKID CONTROL ECU (BI TERMINAL) 
    1. Turn the power switch off.
      Fig 2: Identifying A61 Connector Terminals
      GTY349138Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Check that the ABS MAIN NO. 1 (20 A) and ABS MAIN NO. 2 (7.5 A) fuses are normal.
    3. Make sure that there is no looseness at the locking part and the connecting part of the connector.
    4. Disconnect the skid control ECU connector.
    5. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A61-14 (BI) - Body ground Always 11 to 14 V
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to Skid Control ECU)

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (BI CIRCUIT) 

    OK: Go to next step 

  5. INSPECT SKID CONTROL ECU (BS TERMINAL) 
    1. Measure the voltage according to the value(s) in the table below.
      Fig 3: Identifying A61 Connector Terminals
      GTY349137Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Voltage

      Tester Connection Condition Specified Condition
      A61-15 (BS) - Body ground Always 11 to 14 V
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to Skid Control ECU)

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (BS CIRCUIT) 

    OK → See step   6 

  6. REPLACE BRAKE BOOSTER WITH MASTER CYLINDER. Refer to  REMOVAL [08/2012 - ] 
  7. CHECK FOR INTERMITTENT PROBLEMS. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2012 - ]