LEMON Manuals: Even more car manuals for everyone
Home >> Lexus >> 2018 >> LS 500 Base, AWD >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> Electronically Controlled Brake System (W/ Vacuum Brake Booster) - Diagnostic Codes (3 Of 4) >> ELECTRONICALLY CONTROLLED BRAKE SYSTEM (w/ Vacuum Brake Booster) >> DTC C1422: Master Cylinder Pressure Sensor Zero Point High Malfunction [12/2017 - 09/2018] >> Procedure

DTC C1422: Master Cylinder Pressure Sensor Zero Point High Malfunction [12/2017 - 09/2018]: Procedure

  1. CHECK DTC 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [12/2017 - 09/2018]

      Chassis > ABS/VSC/TRAC > Clear DTCs 

    2. Turn the engine switch off.
    3. Start the engine.
    4. Perform a road test.
    5. Check for DTCs.

      Refer to DTC CHECK / CLEAR [12/2017 - 09/2018]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      Result

      Proceed to
      DTC C1422 is output
      DTCs C1422 and C1380 are output
      DTCs C1422 and C1425 are output

    Result: 

    DTCs C1422 and C1380 are output 

    GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [12/2017 - 09/2018] 

    Result: 

    DTCs C1422 and C1425 are output 

    GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [12/2017 - 09/2018] 

    Result: 

    DTC C1422 is output 

    See step  2

  2. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH ASSEMBLY) 
    1. Connect the Techstream to the DLC3.
    2. Start the engine.
    3. Select the Data List using the Techstream.

      Refer to DATA LIST / ACTIVE TEST [12/2017 - 09/2018]

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Stop Light SW Stop light switch assembly ON or OFF ON: Brake pedal depressed
      OFF: Brake pedal released      		 -

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display
      Stop Light SW
    4. Check that the stop light switch assembly condition observed on the Techstream changes according to brake pedal operation.

      OK

      The Techstream displays ON or OFF according to brake pedal operation.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  5

    Result: 

    OK 

    See step  3

  3. READ VALUE USING TECHSTREAM (MASTER CYLINDER SENSOR) 
    1. Select the Data List using the Techstream.

      Refer to DATA LIST / ACTIVE TEST [12/2017 - 09/2018]

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Master Cylinder Pressure Master cylinder pressure sensor pressure Min.: 0.00 MPa
      Max.: 24.48 MPa      		 Brake pedal operated: Proportional to pedal force
      Brake pedal released: 0.00 to 1.76 MPa      		 -

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display
      Master Cylinder Pressure

      OK

      Data List pressure is within standard range.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [12/2017 - 09/2018] 

    Result: 

    OK 

    See step  4

  4. RECONFIRM DTC 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [12/2017 - 09/2018]

      Chassis > ABS/VSC/TRAC > Clear DTCs 

    2. Turn the engine switch off.
    3. Start the engine.
    4. Drive the vehicle and perform a braking test (decelerate the vehicle by depressing the brake pedal).
    5. Check if the same DTC is output.

      Refer to DTC CHECK / CLEAR [12/2017 - 09/2018]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      Result

      Result Proceed to
      DTC C1422 is not output. A
      DTC C1422 is output. B

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2017 - 09/2018] 

    Result: 

    B 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [12/2017 - 09/2018] 

  5. CHECK STOP LIGHT SWITCH ASSEMBLY INSTALLATION 
    1. Turn the engine switch off.
    2. Check the stop light switch assembly installation.

      Refer to INSTALLATION [12/2017 - 10/2023]

      OK

      The stop light switch assembly installation are normal.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    ADJUST STOP LIGHT SWITCH ASSEMBLY INSTALLATION. Refer to  ADJUSTMENT [12/2017 - 10/2020] 

    Result: 

    OK 

    See step  6

  6. INSPECT STOP LIGHT SWITCH ASSEMBLY 
    1. Remove the stop light switch assembly.

      Refer to REMOVAL [12/2017 - 09/2018]

    2. Inspect the stop light switch assembly.

      Refer to ON-VEHICLE INSPECTION [12/2017 - ]

      OK

      The stop light switch assembly is normal.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE STOP LIGHT SWITCH ASSEMBLY. Refer to  REMOVAL [12/2017 - 09/2018] 

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (STP TERMINAL) 
    1. Turn the engine switch off.
    2. Make sure that there is no looseness at the locking part and the connecting part of the connector.
    3. Disconnect the A9 skid control ECU (brake actuator assembly) connector.
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A9-35 (STP) - Body ground Stop light switch assembly on (Brake pedal depressed) 8 to 14 V
      A9-35 (STP) - Body ground Stop light switch assembly off (Brake pedal released) Below 1.5 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [12/2017 - 09/2018] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT) 

scientia non olet · About LEMON Manuals