ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1252, C1253

DTC Code DTC Name
C1252 Brake Booster Pump Motor on Time Abnormally Long
C1253 Pump Motor Relay

DESCRIPTION

The skid control ECU (brake booster with master cylinder assembly) detects decreases in the accumulator pressure according to the data from the accumulator pressure sensor, and then starts and stops the pump motor by operating the motor relay.

DTC No. Detection Item INF Code DTC Detection Condition Trouble Area Note
C1252 Brake Booster Pump Motor on Time Abnormally Long 311 The pump motor is operating continuously for 178 seconds or more. (When the relay is malfunctioning for 98 seconds or more.)

  • Short in pump motor circuit or pump motor monitor circuit

  • Motor relay stuck

  • Accumulator pressure sensor malfunction

  • Skid control ECU (brake booster with master cylinder assembly)

 Electronically controlled brake system DTC
C1253 Pump Motor Relay

321

322

327

328

  • INF Code: 321, 327, 328


    • An open is detected in the motor relay drive circuit for 0.2 seconds or more.

  • INF Code: 322


    • A short is detected in the motor relay drive circuit for 2 seconds or more.

  • INF Code: 321, 327, 328


    • Open in pump motor circuit or pump motor monitor circuit

    • Skid control ECU (brake booster with master cylinder assembly)

  • INF Code: 322


    • Short in pump motor circuit or pump motor monitor circuit

    • Skid control ECU (brake booster with master cylinder assembly)

 Electronically controlled brake system DTC

WIRING DIAGRAM

A003NTXE06

CAUTION / NOTICE / HINT

Note


  • After replacing the skid control ECU (brake booster with master cylinder assembly), perform linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization after performing "Reset Memory".

    Click here

  • Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE


  1. READ VALUE USING GTS (MOTOR RELAY 1 AND MOTOR RELAY 2)


    1. Select the Data List on the GTS.

      Click here


      Chassis > ABS/VSC/TRC > Data List
      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      ECB Motor Relay Motor relay 1 operation request ON or OFF

      ON: Relay on

      OFF: Relay off

      		 ECB: Electronically Controlled Brake System
      ECB Motor Relay2 Motor relay 2 operation request ON or OFF

      ON: Relay on

      OFF: Relay off

      		 ECB: Electronically Controlled Brake System

      Chassis > ABS/VSC/TRC > Data List
      Tester Display
      ECB Motor Relay
      ECB Motor Relay2

    2. Depress the brake pedal several times and check the operation status of the motor relay 1 and motor relay 2.

      Tech Tips

      Depressing the brake pedal several times drops the accumulator pressure and operates the pump motor.

      Result
      Result Proceed to
      The motor relay 1 and motor relay 2 in the Data List turns on or off by depressing the brake pedal several times. A
      The status of motor relay 1 and motor relay 2 in the Data List does not change even after depressing the brake pedal several times. B

    B

    CHECK HARNESS AND CONNECTOR (MRI TERMINAL) Click here

    A

  2. INSPECT BRAKE BOOSTER PUMP ASSEMBLY


    1. A003KIFC03
      *a

      Component without harness connected

      (Brake Booster Pump Assembly)

      Turn the power switch off.

    2. Make sure that there is no looseness at the locking part and the connecting part of the connector.

      OK
      The connector is securely connected.

    3. Disconnect the A11 brake booster pump assembly connector.

    4. Check both the connector case and the terminals for deformation and corrosion.

      OK
      No deformation or corrosion.

    5. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      2 (BM1) - 4 (GND1) Always Below 10 Ω
      1 (BM2) - 3 (GND2) Always Below 10 Ω
      2 (BM1) - 1 (BM2) Always Below 1 Ω
      4 (GND1) - 3 (GND2) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE BRAKE BOOSTER PUMP ASSEMBLY for LHD: Click here
    REPLACE BRAKE BOOSTER PUMP ASSEMBLY for RHD: Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (GND TERMINAL)


    1. A003OW0C06
      *a

      Front view of wire harness connector

      (to Brake Booster Pump Assembly)

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A11-4 (GND1) - Body ground Always Below 1 Ω
      A11-3 (GND2) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

    OK

  4. READ VALUE USING GTS (ACCUMULATOR PRESSURE)


    1. Reconnect the A11 brake booster pump assembly connector.

    2. Disconnect the A36 brake pedal stroke sensor assembly connector.

    3. Select the Data List on the GTS.

      Click here


      Chassis > ABS/VSC/TRC > Data List
      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      MT Voltage Value MT voltage value Min.: 0.00 V, Max.: 20.00 V

      Pump motor off: 0.00 V

      Pump motor on: 12.00 V

      		 -
      Accumulator Pressure Accumulator pressure output value Min.: 0.00 MPa, Max.: 24.48 MPa

      15.00 to 21.00 MPa

      (Pressure stable and pump motor stopped)

      		 When brake fluid is stored in the accumulator: Accumulator pressure changes in accordance with volume of fluid stored in the accumulator

      Chassis > ABS/VSC/TRC > Data List
      Tester Display
      MT Voltage Value
      Accumulator Pressure

    4. Depress the brake pedal several times to operate the pump motor, then wait until it stops.

    5. After the pump motor stops, wait for 30 seconds, then check the drop in the accumulator pressure sensor output value and the state of the pump motor.

      Tech Tips


      • This inspection checks whether an accumulator pressure sensor malfunction, internal brake actuator (brake booster with master cylinder assembly) leak or prolonged operation due to detection of low pressure caused by accumulator deterioration, caused the DTC to be stored.

      • If the brake fluid level in the brake master cylinder reservoir assembly (brake booster with master cylinder assembly) drops, an external brake fluid leak is suspected.

      Result
      Result Proceed to
      The drop in the accumulator pressure sensor output value is less than 2.50 MPa 30 seconds after the pump motor stops, and the pump motor does not operate within 30 seconds after the pump motor stops. A
      The drop in the accumulator pressure sensor output value is 2.50 MPa or more 30 seconds after the pump motor stops, or the pump motor operates within 30 seconds after the pump motor stops. B

    B

    READ VALUE USING GTS (SERVO PRESSURE) Click here

    A

  5. RECONFIRM DTC


    1. Turn the power switch off.

    2. Reconnect the A36 brake pedal stroke sensor assembly connector.

    3. Clear the DTCs.

      Click here


      Chassis > ABS/VSC/TRC > Clear DTCs

    4. Turn the power switch off.

    5. Turn the power switch on (IG).

    6. Check if the same DTC is output.

      Click here


      Chassis > ABS/VSC/TRC > Trouble Codes
      Result
      Result Proceed to
      DTCs C1252 and C1253 are not output. A
      DTCs C1252 and/or C1253 are output. B

    A

    USE SIMULATION METHOD TO CHECK Click here

    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for LHD: Click here
    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for RHD: Click here

  6. READ VALUE USING GTS (SERVO PRESSURE)


    1. Turn the power switch off.

    2. Reconnect the A36 brake pedal stroke sensor assembly connector.

    3. Select the Active Test on the GTS.

      Click here


      Chassis > ABS/VSC/TRC > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      ECB Solenoid (SLR) Linear solenoid reduction valve (SLR) Solenoid ON/OFF ECB: Electronically Controlled Brake System

      Chassis > ABS/VSC/TRC > Active Test
      Tester Display
      ECB Solenoid (SLR)

    4. Select the Data List on the GTS.

      Click here


      Chassis > ABS/VSC/TRC > Data List
      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Servo Pressure Pressure value of servo Min.: 0.00 MPa, Max.: 24.48 MPa Brake pedal released: 0.00 to 2.10 MPa Brake pedal is being depressed: Changes in proportion to the depression force of the brake pedal

      Chassis > ABS/VSC/TRC > Data List
      Tester Display
      Servo Pressure

    5. Perform the Active Test and operate the linear solenoid (SLR) in the brake actuator (brake booster with master cylinder assembly).

    6. Check that the servo pressure output value does not increase when performing the Active Test.

      OK
      The servo pressure output value does not increase when performing the Active Test.

      Tech Tips

      If the servo pressure output value increases, an internal brake fluid leak in the brake actuator (brake booster with master cylinder assembly) is suspected.

      Result
      Result Proceed to
      The servo pressure output value increases. A
      The servo pressure output value does not increase. B

    A

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for LHD: Click here
    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for RHD: Click here

    B

    REPLACE BRAKE BOOSTER PUMP ASSEMBLY for LHD: Click here
    REPLACE BRAKE BOOSTER PUMP ASSEMBLY for RHD: Click here

  7. CHECK HARNESS AND CONNECTOR (MRI TERMINAL)


    1. B006HQOC66
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

      Turn the power switch off.

    2. Make sure that there is no looseness at the locking part and the connecting part of the connector.

      OK
      The connector is securely connected.

    3. Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.

    4. Check both the connector case and the terminals for deformation and corrosion.

      OK
      No deformation or corrosion.

    5. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      A32-2 (MRI1) - Body ground Always 11 to 14 V
      A32-28 (MRI2) - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (MRI CIRCUIT)

    OK

  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 connector.

      OK
      The connector is securely connected.

    2. Disconnect the A11 brake booster pump assembly connector.

    3. Check both the connector case and the terminals for deformation and corrosion.

      OK
      No deformation or corrosion.

    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A32-1 (MRO1) - A11-2 (BM1) Always Below 1 Ω
      A32-1 (MRO1) or A11-2 (BM1) - Body ground Always 10 kΩ or higher
      A32-27 (MRO2) - A11-1 (BM2) Always Below 1 Ω
      A32-27 (MRO2) or A11-1 (BM2) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for LHD: Click here
    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for RHD: Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR