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Home >> Lexus >> 2021 >> LC 500 2D Coupe >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> Electronically Controlled Brake System - Diagnostic Codes (Coupe) (3 Of 4) >> Electronically Controlled Brake System >> DTC C1341/62: Front Hydraulic System RH Malfunction; DTC C1342/63: Front Hydraulic System LH Malfunction; DTC C1343/64: Rear Hydraulic System RH Malfunction; DTC C1344/65: Rear Hydraulic System LH Malfunction [03/2017 - 09/2018] >> Procedure

DTC C1341/62: Front Hydraulic System RH Malfunction; DTC C1342/63: Front Hydraulic System LH Malfunction; DTC C1343/64: Rear Hydraulic System RH Malfunction; DTC C1344/65: Rear Hydraulic System LH Malfunction [03/2017 - 09/2018]: Procedure

  1. CHECK DTC 
    1. 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 C1341/62, C1342/63, C1343/64 and/or C1344/65, are output. A
      DTC C1364/61 is output. B

    Result: 

    B 

    GO TO DTC (C1364/61). Refer to  DTC C1246/46: Master Cylinder Pressure Sensor Malfunction; DTC C1364/61: Wheel Cylinder Pressure Sensor Malfunction [03/2017 - 09/2018] 

    Result: 

    A 

    See step  2

  2. CHECK FOR FLUID LEAK 
    1. Check that there are no fluid leaks in the brake lines between the brake actuator assembly and the wheel cylinders.
    2. Check that the brakes are not dragging.

      OK

      There are no fluid leaks or dragging.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE APPLICABLE PART 

    Result: 

    OK 

    See step  3

  3. PERFORM AIR BLEEDING 
    1. Bleed the air from the front and rear brake systems.

      Refer to BLEEDING [03/2017 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU ASSEMBLY AND BRAKE ACTUATOR ASSEMBLY - BODY GROUND) 
    1. Make sure that there is no looseness at the locking part and the connecting part of the connectors.
    2. Disconnect the A11 and A8 skid control ECU assembly connectors.
    3. Disconnect the A7 brake actuator assembly connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester connection Condition Specified condition
      A8-8 (E) or A7-14 (E)- Body ground Always 10 kΩ or higher
      A8-9 (VCM) or A7-10 (VCM) - Body ground Always 10 kΩ or higher
      A8-18 (PRL) or A7-11 (PRL) - Body ground Always 10 kΩ or higher
      A8-21 (PAC1) or A7-15 (PAC1) - Body ground Always 10 kΩ or higher
      A8-30 (PMC1) or A7-13 (PMC1)- Body ground Always 10 kΩ or higher
      A8-31 (PCK1) or A7-12 (PCK1)- Body ground Always 10 kΩ or higher
      A8-32 (PFR) or A7-9 (PFR) - Body ground Always 10 kΩ or higher
      A11-15 (E2) or A7-16 (E2) - Body ground Always 10 kΩ or higher
      A11-16 (VCM2) or A7-5 (VCM2) - Body ground Always 10 kΩ or higher
      A11-23 (PFL) or A7-4 (PFL) - Body ground Always 10 kΩ or higher
      A11-24 (PRR) or A7-6 (PRR)- Body ground Always 10 kΩ or higher
      A11-28 (PMC2) or A7-8 (PMC2) - Body ground Always 10 kΩ or higher
      A11-29 (PCK2) or A7-7 (PCK2)- Body ground Always 10 kΩ or higher

      Result

      Result
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  5

  5. READ VALUE USING TECHSTREAM (WHEEL CYLINDER PRESSURE SENSOR) 
    1. Reconnect the A11 and A8 skid control ECU assembly connectors.
    2. Reconnect the A7 brake actuator assembly connector.
    3. Connect an LSPV gauge set.
    4. Connect the Techstream to the DLC3.
    5. Turn the engine switch on (IG).
    6. 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
      FR W/C Sensor Front wheel cylinder pressure sensor RH Min.: 0.00 V, Max.: 5.00 V Brake pedal released: 0.30 to 0.70 V Reading increases when brake pedal is depressed
      FL W/C Sensor Front wheel cylinder pressure sensor LH Min.: 0.00 V, Max.: 5.00 V Brake pedal released: 0.30 to 0.70 V Reading increases when brake pedal is depressed
      RR W/C Sensor Rear wheel cylinder pressure sensor RH Min.: 0.00 V, Max.: 5.00 V Brake pedal released: 0.30 to 0.70 V Reading increases when brake pedal is depressed
      RL W/C Sensor Rear wheel cylinder pressure sensor LH Min.: 0.00 V, Max.: 5.00 V Brake pedal released: 0.30 to 0.70 V Reading increases when brake pedal is depressed

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display
      FR W/C Sensor
      FL W/C Sensor
      RR W/C Sensor
      RL W/C Sensor
    7. Check the output values of the wheel cylinder pressure sensor at each hydraulic pressure level during the electronically controlled brake system control.

      Standard Voltage

      FOR FRONT WHEEL CYLINDER

      Hydraulic Pressure
      MPa (kgf/cm2 , psi)      		 FR W/C Sensor
      (Tester Display)      		 FL W/C Sensor
      (Tester Display)
      1.76 (17.9, 255) 0.66 to 1.06 V 0.66 to 1.06 V
      5.22 (53.2, 757) 1.37 to 1.77 V 1.37 to 1.77 V
      FOR REAR WHEEL CYLINDER

      Hydraulic Pressure
      MPa (kgf/cm2 , psi)      		 RR W/C Sensor
      (Tester Display)      		 RL W/C Sensor
      (Tester Display)
      1.76 (17.9, 255) 0.66 to 1.06 V 0.66 to 1.06 V
      5.22 (53.2, 757) 1.37 to 1.77 V 1.37 to 1.77 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [03/2017 - 05/2023] 

    Result: 

    OK 

    See step  6

  6. CHECK BRAKE DISC 
    1. Turn the engine switch off.
    2. Disconnect the A3 brake pedal stroke sensor assembly connector.
    3. Perform a road test according to Freeze Frame Data or customer problem analysis. While driving, check for abnormal brake pedal vibration caused by brake discs that are worn or have excess runout.

      OK

      Brake pedal does not vibrate during braking.

      HINT: 

      • An unevenly worn disc may vibrate the caliper piston and cause fluctuations in brake line pressure, triggering a malfunction detection condition.
      • The brake pedal does not kick back due to caliper piston vibration during electronically controlled brake system control.
      • If the brake pedal stroke sensor assembly connector is disconnected, the fail-safe function will prohibit electronically controlled brake system control.
      • The Active Test does not prohibit electronically controlled brake system control when the vehicle is being driven, so disconnect the brake pedal stroke sensor assembly connector before continuing with inspection.
      • Uneven disc wear can be checked by measuring the disc thickness variation.

        for Front Brake: Refer to INSPECTION [03/2017 - 06/2019]

        for Rear Brake: Refer to INSPECTION [03/2017 - 05/2023]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE BRAKE DISC 

    Result: 

    OK 

    See step  7

  7. RECONFIRM DTC 
    1. Reconnect the A3 brake pedal stroke sensor assembly connector.
    2. Clear the DTCs.

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

      Chassis > ABS/VSC/TRAC > Clear DTCs 

    3. Turn the engine switch off.
    4. Start the engine.
    5. Perform a road test under the same malfunction conditions recreated based on the Freeze Frame Data or customer problem analysis.
    6. 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 C1341/62, C1342/63, C1343/64 and C1344/65 are not output. A
      DTCs C1341/62, C1342/63, C1343/64 and/or C1344/65 are output. B

    Result: 

    A 

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

    Result: 

    B 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [03/2017 - 05/2023] 

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