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Home >> Lexus >> 2008 >> GS 350 RWD >> Repair and Diagnosis >> Brakes >> Traction Control >> Brake Control >> Electronically Controlled Brake System >> DTC C1378/44 Capacitor Communication Malfunction >> Inspection Procedure

Inspection Procedure

NOTE: When replacing the skid control ECU, perform initialization of linear solenoid valve and calibration (see INITIALIZATION  ).
  1. INSPECT BRAKE CONTROL POWER SUPPLY 
    1. Disconnect the brake control power supply connector.
    2. Measure the voltage according to the value (s) in the table below.

      Voltage 

      VOLTAGE REFERENCE CHART

      Tester Connection Specified Condition
      U27-5 (IG1) - Body ground 10 to 14 V
    3. Measure the resistance according to the value (s) in the table below.

      Resistance 

      RESISTANCE REFERENCE CHART

      Tester Connection Specified Condition
      U27-14 (GND) - Body ground Below 1 Ω

    NG : REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 OR GND CIRCUIT) 

    Fig 1: Inspecting Brake Control Power Supply
    G05807207Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK : Go to Next Step 

  2. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU TO BRAKE CONTROL POWER SUPPLY) 
    1. Disconnect the skid control ECU and brake control power supply connector.
    2. Measure the resistance according to the value (s) in the table below.

      Resistance 

      RESISTANCE REFERENCE CHART

      Tester Connection Specified Condition
      A13-8 (ENA) - U27-12 (ENA) Below 1 Ω
      A13-23 (FAIL) - U27-13 (FAIL) Below 1 Ω
    3. Measure the resistance according to the value (s) in the table below.

      Resistance 

      RESISTANCE REFERENCE CHART

      Tester Connection Specified Condition
      A13-8 (ENA) - Body ground 10 kΩ or higher
      A13-23 (FAIL) - Body ground 10 kΩ or higher

    NG : REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Fig 2: Checking Harness And Connector (Skid Control ECU To Brake Control Power Supply)
    G05297106Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK : Go to Next Step 

  3. RECONFIRM DTC 
    1. Clear the DTC (see DTC CHECK/CLEAR  ).
    2. Turn the engine switch on (IG).
    3. Check if the same DTC is recorded (see DTC CHECK/CLEAR  ).

      HINT:

      Reinstall the sensor, connectors, etc. and restore the vehicle to its prior condition before rechecking for DTCs.

      Result 

      RESULT REFERENCE

      Display (DTC Output) Proceed To
      DTC (C1378/44) Is not output A
      DTC (C1378/44) is output B

    B : Go to step 4 

    A : END 

  4. CHECK FREEZE FRAME DATA 
    1. Check the information code from the Freeze Frame Data memorized when the DTC (C1378/44) is stored (see FREEZE FRAME DATA  ).

      Result 

      RESULT REFERENCE

      Condition Proceed To
      Information code is not output A
      Information code (112) Is output B

    B : REPLACE BRAKE CONTROL POWER SUPPLY 

    A : REPLACE SKID CONTROL ECU 

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