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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Electrical >> Starter >> Stop And Start System - Diagnostic Codes (1 Of 3) >> Stop And Start System >> DTC P0555-00: Brake Booster Pressure Sensor (running); DTC P0555-2A: Brake Booster Pressure Sensor Signal Stuck In Range [12/2019 - 10/2022] >> Procedure

DTC P0555-00: Brake Booster Pressure Sensor (running); DTC P0555-2A: Brake Booster Pressure Sensor Signal Stuck In Range [12/2019 - 10/2022]: Procedure

  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0555-00 OR P0555-2A) 
    1. Read the DTCs.

      Powertrain > Stop and Start > Trouble Codes 

      Result

      Result Proceed to
      DTC P0555-00 or P0555-2A is output A
      DTC P0555-00 or P0555-2A and other DTCs output B

      HINT: 

      If any DTCs other than P0555-00 or P0555-2A are output, troubleshoot those DTCs first.

    Result: 

    B 

    GO TO DIAGNOSTIC TROUBLE CODE CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [12/2019 - 10/2022] 

    Result: 

    A 

    See step  2

  2. READ VALUE USING GTS (BRAKE BOOST PRESSURE) 
    1. Start the engine and warm it up.
    2. Turn the ignition switch off. (*1)
    3. Turn the ignition switch to ON. (*2)

      HINT: 

      Do not start the engine.

    4. Depress the brake pedal 5 times and read the changes in the following pressure value.

      Powertrain > Stop and Start > Data List 

      Tester Display
      Brake Boost Pressure

      OK

      GTS Display Condition Normal Condition
      Brake Boost Pressure
      • Ignition switch ON
      • Brake pedal depressed 5 times
      		 Changes by 20 kPa (150 mmHg, 5.91 in. Hg) or higher
      NOTE:

      Because it is hard to cause variation in the internal pressure before and after depressing the brake pedal if the brake booster internal pressure is high before depressing the brake pedal, do not operate the brake pedal as much as possible between operations (*1) and (*2).

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ] 

    Result: 

    NG 

    See step  3

  3. INSPECT VACUUM HOSE (BRAKE BOOSTER HOSE) 
    1. Visually check the vacuum hose (brake booster hose) for cracks or clogging.

      HINT: 

      If the braking force is abnormal, inspect the brake booster assembly.

      OK

      No cracks or clogging in the vacuum hose (brake booster hose).

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE VACUUM HOSE 

    Result: 

    OK 

    See step  4

  4. REPLACE VACUUM SENSOR ASSEMBLY 

    Refer to REMOVAL [12/2019 - 10/2022]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  5

  5. CLEAR DTC 
    1. Clear the DTC.

      Powertrain > Stop and Start > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  6

  6. CHECK DTC OUTPUT 
    1. Start the engine and warm it up.
    2. Drive the vehicle at 30 km/h (19 mph) or more and stop the vehicle. Repeat this driving pattern 30 times to allow the brake booster vacuum to change.

      Powertrain > Stop and Start > Data List 

      Tester Display
      Brake Boost Pressure
      WARNING:

      When performing Confirmation Driving Pattern, obey all speed limits and traffic laws.

    3. Stop the vehicle.
    4. Check that no DTCs are output.

      Powertrain > Stop and Start > Trouble Codes 

      Result

      Result Proceed to
      DTCs are not output A
      DTC P0555-00 or P0555-2A is output B

    Result: 

    A 

    END 

    Result: 

    B 

    REPLACE ENGINE STOP AND START ECU. Refer to  REMOVAL [12/2019 - 10/2022] 

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