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Home >> Toyota >> 2020 >> Mirai >> Repair and Diagnosis (Single Page) >> Brakes >> Mechanical - Hydraulic >> Electronically Controlled Brake System - Diagnostic Codes (1 Of 2) >> Electronically Controlled Brake System >> DTC C1252-52: Brake Booster Pump Motor on Time Abnormally Long; DTC C1253-53: Pump Motor Relay Malfunction [06/2015 - ] >> Procedure

DTC C1252-52: Brake Booster Pump Motor on Time Abnormally Long; DTC C1253-53: Pump Motor Relay Malfunction [06/2015 - ]: Procedure

  1. PERFORM ACTIVE TEST USING TECHSTREAM (ABS MOTOR RELAY) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Select the Active Test on the Techstream.

      Refer to DATA LIST / ACTIVE TEST [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Active Test 

      Tester Display Measurement Item Control Range Diagnostic Note
      ECB Motor Relay ABS motor relay Relay ON/OFF ECB: Electronically Controlled Brake System

      Chassis > ABS/VSC/TRAC > Active Test 

      Tester Display
      ECB Motor Relay
    4. Select the Data List on the Techstream.

      Refer to DATA LIST / ACTIVE TEST [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      ECB Motor Relay ABS motor relay ON or OFF ON: Relay on
      OFF: Relay off      		 ECB: Electronically Controlled Brake System

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display
      ECB Motor Relay
    5. Check the operating condition of the ABS motor relay when operating it with the Techstream.

      Result

      Result Proceed to
      ABS motor relay in the Data List turns ON/OFF using the Active Test. A
      ABS motor relay in the Data List does not change using the Active Test. B

    Result: 

    B 

    See step  7

    Result: 

    A 

    See step  2

  2. INSPECT BRAKE BOOSTER PUMP ASSEMBLY 
    1. Turn the power switch off.
      GTY609161Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component without harness connected
      (Brake Booster Pump Assembly)
    2. Make sure that there is no looseness at the locking part and the connecting part of the connectors.
    3. Disconnect the A35 and A36 brake booster pump assembly connectors.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A35-1 (BM1) - A35-2 (GND1) Always Below 10 Ω
      A36-2 (BM2) - A36-1 (GND2) Always Below 10 Ω
      A35-1 (BM1) - A36-2 (BM2) Always Below 1 Ω
      A35-2 (GND1) - A36-1 (GND2) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE BRAKE BOOSTER PUMP ASSEMBLY. Refer to  REMOVAL [06/2015 - 11/2018]  , or refer to  REMOVAL [11/2018 - ] 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (GND TERMINAL) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A35-2 (GND1) - Body ground Always Below 1 Ω
      A36-1 (GND2) - Body ground Always Below 1 Ω
      GTY583576Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Brake Booster Pump Assembly)

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT) 

    Result: 

    OK 

    See step  4

  4. READ VALUE USING TECHSTREAM (ACCUMULATOR PRESSURE SENSOR) 
    1. Reconnect the A35 and A36 brake booster pump assembly connectors.
    2. Connect the Techstream to the DLC3.
    3. Turn the power switch on (IG).
    4. Select the Data List on the Techstream.

      Refer to DATA LIST / ACTIVE TEST [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Accumulator Sensor Accumulator pressure sensor Min.: 0.00 V, Max.: 5.00 V Specified value: 2.90 to 4.20 V When brake fluid is stored in the accumulator: Accumulator pressure changes in accordance with volume of fluid stored in the accumulator

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display
      Accumulator Sensor
    5. Depress the brake pedal 4 or 5 times to operate the pump motor.
    6. Wait for 30 seconds without depressing the brake pedal.
    7. Check that the accumulator pressure sensor output value change is within the specified range.

      OK

      Accumulator pressure sensor output value change is less than 0.55 V.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  6

    Result: 

    OK 

    See step  5

  5. RECONFIRM DTC 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Clear DTCs 

    2. Turn the power switch off.
    3. Turn the power switch on (IG).
    4. Check if the same DTC is output.

      Refer to DTC CHECK / CLEAR [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      Result

      Result Proceed to
      DTCs C1252/52 and C1253/53 are not output. A
      DTCs C1252/52 and/or C1253/53 are output. B

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [06/2015 - 11/2018]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2018 - ] 

    Result: 

    B 

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to  REMOVAL [06/2015 - 11/2018]  , or refer to  REMOVAL [11/2018 - ] 

  6. PERFORM ACTIVE TEST USING TECHSTREAM (SOLENOID VALVE) 
    1. Select the Active Test on the Techstream.

      Refer to DATA LIST / ACTIVE TEST [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Active Test 

      Tester Display Measurement Item Control Range Diagnostic Note
      ECB Solenoid (SMC/SRC/SCC) Switching solenoid valve (SMC/SRC/SCC) Solenoid ON/OFF
      • Operation sound of solenoid (clicking sound) can be heard
      • ECB: Electronically Controlled Brake System

      Chassis > ABS/VSC/TRAC > Active Test 

      Tester Display
      ECB Solenoid (SMC/SRC/SCC)

      HINT: 

      The Active Test can be performed when the following conditions are met.

      • ABS main relay is on.
      • Shift lever is in P.
      • Parking brake is applied.
      • Vehicle speed is 0 km/h (0 mph).
    2. Perform the Active Test of the solenoid using the Techstream.
    3. Select the Data List on the Techstream.

      Refer to DATA LIST / ACTIVE TEST [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Wheel Cylinder Pressure Sensor Wheel cylinder pressure sensor Min.: 0.00 V, Max.: 5.00 V Brake pedal released: 0.10 to 0.90 V Reading increases when brake pedal is depressed

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display
      Wheel Cylinder Pressure Sensor
    4. Check that the output value of the wheel cylinder pressure sensor does not increase.

      OK

      The output value of the wheel cylinder pressure sensor does not increase.

      HINT: 

      If the output value increases, there may be brake fluid leaks in the brake actuator.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BRAKE BOOSTER PUMP ASSEMBLY. Refer to  REMOVAL [06/2015 - 11/2018]  , or refer to  REMOVAL [11/2018 - ] 

    Result: 

    NG 

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to  REMOVAL [06/2015 - 11/2018]  , or refer to  REMOVAL [11/2018 - ] 

  7. CHECK HARNESS AND CONNECTOR (MRI TERMINAL) 
    1. Turn the power switch off.
      GTY550681Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))
    2. Make sure that there is no looseness at the locking part and the connecting part of the connector.
    3. Disconnect the A63 skid control ECU (brake booster with master cylinder assembly) connector.
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A63-1 (MRI1) - Body ground Always 11 to 14 V
      A63-2 (MRI2) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (MRI CIRCUIT) 

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - BRAKE BOOSTER PUMP ASSEMBLY) 
    1. Make sure that there is no looseness at the locking part and the connecting part of the connectors.
    2. Disconnect the A35 and A36 brake booster pump assembly connectors.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A63-29 (MRO1) - A35-1 (BM1) Always Below 1 Ω
      A63-29 (MRO1) or A35-1 (BM1) - Body ground Always 10 kΩ or higher
      A63-30 (MRO2) - A36-2 (BM2) Always Below 1 Ω
      A63-30 (MRO2) or A36-2 (BM2) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to  REMOVAL [06/2015 - 11/2018]  , or refer to  REMOVAL [11/2018 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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