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DTC P1578: Brake System Malfunction [08/2013 - ]: Procedure

WARNING: This page is about a different car, the 2014 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK FOR DTCs (ABS/VSC/TRC) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Chassis / ABS/VSC/TRC / Trouble Codes.
    5. Check for DTCs.

      Result

      Result Proceed to
      DTC is not output A
      DTC is output B
    6. Turn the power switch off.

    B → See step   5 

    A: Go to next step 

  2. CHECK FOR DTCs (DTC P1578) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Perform the following to make sure that the DTC detection conditions are met.

      HINT: 

      If the detection conditions are not met, the malfunction cannot be detected.

      1. Drive the vehicle at a speed for which cruise control operation is possible.
      2. Turn the cruise control system on using the cruise control switch (ON-OFF button).
      3. Push the cruise control switch to -/SET to begin control of vehicle speed using the cruise control system.
    5. Enter the following menus: Powertrain / Cruise Control / Trouble Codes.
    6. Check for DTCs.

      Result

      Result Proceed to
      DTC is not output A
      DTC P1578 is output B
    7. Turn the power switch off.

    B → See step   3 

    A → See step   6 

  3. REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY 

    Refer to REMOVAL [08/2013 - ]

    NEXT: Go to next step 

  4. CHECK FOR DTCs (DTC P1578) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs. Refer to DTC CHECK / CLEAR [08/2013 - ] .
    5. Perform the following to make sure that the DTC detection conditions are met.

      HINT: 

      If the detection conditions are not met, the malfunction cannot be detected.

      1. Drive the vehicle at a speed for which cruise control operation is possible.
      2. Turn the cruise control system on using the cruise control switch (ON-OFF button).
      3. Push the cruise control switch to -/SET to begin control of vehicle speed using the cruise control system.
    6. Enter the following menus: Powertrain / Cruise Control / Trouble Codes.
    7. Check for DTCs.

      Result

      Result Proceed to
      DTC is not output A
      DTC P1578 is output B
    8. Turn the power switch off.

    B → See step   7 

    A → END 

  5. GO TO ELECTRONICALLY CONTROLLED BRAKE SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2013 - ] 
  6. USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2013 - ] 
  7. REPLACE POWER MANAGEMENT CONTROL ECU. Refer to  REMOVAL [08/2013 - ] 
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