ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1252/52, C1253/53

DTC Code DTC Name
C1252/52 Brake Booster Pump Motor on Time Abnormally Long
C1253/53 Pump Motor Relay Malfunction

DESCRIPTION

The skid control ECU 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 Code INF Code DTC Detection Condition Trouble Area
C1252/52 311 The pump motor is operating continuously for 178 seconds or more. (When relay malfunction is 98 seconds or more.)

  • Short in motor circuit or motor monitor circuit

  • Motor relay stuck

  • Accumulator pressure sensor malfunction in brake actuator

  • Brake booster with master cylinder (Skid control ECU)
C1253/53 321 With the IG1 terminal voltage 9.5 V or more, the motor drive monitor remains off for 0.2 seconds or more after a motor drive on request.

  • Open in motor circuit or motor monitor circuit

  • Brake booster with master cylinder (Skid control ECU)
↑ 322 The motor drive monitor remains on for 2 seconds or more after a motor drive off request.

  • Short in motor circuit or motor monitor circuit

  • Brake booster with master cylinder (Skid control ECU)
↑ 323 The skid control ECU internal motor drive logical inconsistency continues for 2 seconds or more. Brake booster with master cylinder (Skid control ECU)
↑ 324 An open circuit in both skid control ECU internal motor relays 1 and 2.

  • Open in motor circuit or motor monitor circuit

  • Brake booster with master cylinder (Skid control ECU)
↑ 325 An open circuit in both skid control ECU internal motor relays 1 and 3. ↑
↑ 326 An open circuit in both skid control ECU internal motor relays 2 and 3. ↑
↑ 327 An open circuit in skid control ECU internal motor relay 1. ↑
↑ 328 An open circuit in skid control ECU internal motor relay 2. ↑
↑ 329 An open circuit in skid control ECU internal motor relay 3. ↑

WIRING DIAGRAM

A005BQ2E01
*a MAIN
*b Auxiliary Battery
*c Brake Booster Pump
*d Brake Booster with Master Cylinder

CAUTION / NOTICE / HINT

Note

When replacing the brake booster with master cylinder (skid control ECU or brake actuator), perform initialization and calibration of the linear solenoid valve Click here.

PROCEDURE


  1. PERFORM ACTIVE TEST USING GTS (ABS MOTOR RELAY)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Select the Active Test on the GTS Click here.

      ABS/VSC/TRC
      Tester Display Test Part Control Range Diagnostic Note
      ECB* Motor Relay ABS motor relay Relay ON/OFF -

      *: Electronically Controlled Brake System

    4. Select the Data List on the GTS Click here.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      ECB* Motor Relay ABS motor relay / ON or OFF

      ON: Relay on

      OFF: Relay off

      		 -

      *: Electronically Controlled Brake System

    5. Check the operating condition of the ABS motor relay when operating it using the GTS.

      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

    B

    INSPECT SKID CONTROL ECU (MRI TERMINAL) Click here

    A

  2. INSPECT BRAKE BOOSTER PUMP


    1. A005EW4E03
      Text in Illustration
      *a

      Component without harness connected

      (Brake Booster Pump)

      Turn the power switch off (lock).

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

    3. Disconnect the brake booster pump connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A17-1 (BM1) - A17-2 (GND1) Always Below 10 Ω
      A18-2 (BM2) - A18-1 (GND2) Always Below 10 Ω
      A17-1 (BM1) - A18-2 (BM2) Always Below 1 Ω
      A17-2 (GND1) - A18-1 (GND2) Always Below 1 Ω

    NG

    REPLACE BRAKE BOOSTER PUMP Click here

    OK

  3. INSPECT BRAKE BOOSTER PUMP (GND TERMINAL)


    1. A005E00E01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Brake Booster Pump)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A17-2 (GND1) - Body ground Always Below 1 Ω
      A18-1 (GND2) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

    OK

  4. READ VALUE USING GTS (ACCUMULATOR PRESSURE SENSOR)


    1. Reconnect the brake booster pump connectors.

    2. Connect the GTS to the DLC3.

    3. Turn the power switch on (IG).

    4. Select the Data List on the GTS Click here.

      ABS/VSC/TRC
      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

    5. Wait for 30 seconds without depressing the brake pedal.

    6. Check that the accumulator pressure sensor output values change is within the specified range.

      OK
      Accumulator pressure sensor output values change is within 0.55 V.

    NG

    PERFORM ACTIVE TEST USING GTS (SOLENOID VALVE) Click here

    OK

  5. RECONFIRM DTC


    1. Turn the power switch off (lock).

    2. Clear the DTCs Click here.

    3. Turn the power switch on (IG).

    4. Check if the same DTC is recorded Click here.

      Result
      Result Proceed to
      DTCs (C1252/52 and C1253/53) are not output A
      DTCs (C1252/52 and/or C1253/53) are output (for LHD) B
      DTCs (C1252/52 and/or C1253/53) are output (for RHD) C

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

    C

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

  6. INSPECT SKID CONTROL ECU (MRI TERMINAL)


    1. A005BNRE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU)

      Turn the power switch off (lock).

    2. Check that the ABS MTR1 (30 A) and ABS MTR2 (30 A) fuses are normal.

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

    4. Disconnect the skid control ECU connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A58-1 (MRI1) - Body ground Always 11 to 14 V
      A58-2 (MRI2) - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (MRI CIRCUIT)

    OK

  7. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BRAKE BOOSTER PUMP)


    1. Make sure that there is no looseness at the locking part and the connecting part of the connectors.

    2. Disconnect the brake booster pump connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A58-29 (MRO1) - A17-1 (BM1) Always Below 1 Ω
      A58-29 (MRO1) - Body ground Always 10 kΩ or higher
      A58-30 (MRO2) - A18-2 (BM2) Always Below 1 Ω
      A58-30 (MRO2) - Body ground Always 10 kΩ or higher
      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

    A

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  8. PERFORM ACTIVE TEST USING GTS (SOLENOID VALVE)


    1. Select the Active Test on the GTS Click here.

      Tech Tips

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


      • ABS main relay is on.

      • Park (P) is selected.

      • Parking brake is applied.

      • Vehicle speed is 0 km/h (0 mph).

      ABS/VSC/TRC
      Tester Display Test Part 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

      *: Electronically Controlled Brake System

    2. Perform the Active Test of the solenoid using the GTS.

    3. Select the Data List on the GTS Click here.

      ABS/VSC/TRC
      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 When brake pedal released: 0.10 to 0.90 V Reading increases when brake pedal is depressed

    4. Check that the output value of the wheel cylinder does not increase.

      OK
      The output value of the wheel cylinder does not increase.

      Tech Tips

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

      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    A

    REPLACE BRAKE BOOSTER PUMP Click here

    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

    C

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here