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 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.

The skid control ECU assembly usually drives the motor relay 1 for electronically controlled brake system control, and the motor relay 2 for ABS control. If either of them is malfunctioning, the other will substitute.

DTC Code INF Code DTC Detection Condition Trouble Area
C1252/52 130 Motor relay is on for at least 3 minutes.

  • Motor circuit or motor monitor circuit

  • ABS MOTOR NO. 1 relay

  • ABS MOTOR NO. 2 relay

  • Accumulator pressure sensor

  • Fluid leak
C1253/53 134 MTT input is less than 3.5 V for at least 1 second or more when linear solenoid power source voltage 1 (BS1) is 9.5 V or more, either of +BI1 or +BI2 voltage is 7 V or more, and motor relay 1 is on.

  • ABS MOTOR NO. 1 relay

  • ABS MOTOR NO. 1 relay circuit

  • Motor circuit or motor monitor circuit
↑ 138 MTT input is less than 3.5 V for at least 1 second or more when linear solenoid power source voltage 2 (BS2) is 9.5 V or more, either of +BI1 or +BI2 voltage is 7 V or more, and motor relay 1 is on.

  • ABS MOTOR NO. 2 relay

  • ABS MOTOR NO. 2 relay circuit

  • Motor circuit or motor monitor circuit
↑ 140 MTT input is 3.5 V or more for at least 2 seconds when motor relay 1 and 2 are off.

  • ABS MOTOR NO. 1 relay circuit

  • ABS MOTOR NO. 2 relay circuit

  • Motor circuit or motor monitor circuit

WIRING DIAGRAM

A01FSLNE02

INSPECTION PROCEDURE

Note


  • When replacing the skid control ECU assembly or brake actuator assembly, perform initialization and calibration of the linear solenoid valve Click here.

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

PROCEDURE


  1. PERFORM ACTIVE TEST USING GTS (ECB* 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 Operation sound of relay (clicking sound) and motor can be heard
      ECB* Motor Relay2 ABS motor relay 2 Relay ON/OFF Operation sound of relay (clicking sound) and motor can be heard

      *: Electronically Controlled Brake System

    4. Check the operation sound of the ABS motor relay and motor when operating it using the GTS.

      OK
      The operation sound of the ABS motor relay and motor should be heard.

    NG

    INSPECT ABS MOTOR RELAY Click here

    OK

  2. INSPECT BRAKE ACTUATOR ASSEMBLY


    1. A01FTLYE17
      Text in Illustration
      *A for LHD
      *B for RHD
      *a

      Component without harness connected

      (Brake Actuator Assembly)

      Turn the power switch off.

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

    3. Disconnect the A12 brake actuator assembly connector.

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

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      2 (BM1) - 31 (GND1) Always Below 1 Ω
      2 (BM1) - 32 (GND2) Always Below 1 Ω
      1 (BM2) - 31 (GND1) Always Below 1 Ω
      1 (BM2) - 32 (GND2) Always Below 1 Ω
      2 (BM1) - 33 (MTT) Always 450 to 550 Ω
      1 (BM2) - 33 (MTT) Always 450 to 550 Ω
      for RHD
      Tester Connection Condition Specified Condition
      31 (BM1) - 1 (GND1) Always Below 1 Ω
      31 (BM1) - 2 (GND2) Always Below 1 Ω
      32 (BM2) - 1 (GND1) Always Below 1 Ω
      32 (BM2) - 2 (GND2) Always Below 1 Ω
      31 (BM1) - 3 (MTT) Always 450 to 550 Ω
      32 (BM2) - 3 (MTT) Always 450 to 550 Ω

    NG

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU ASSEMBLY - BRAKE ACTUATOR ASSEMBLY)


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

    2. Disconnect the A14 skid control ECU assembly connector.

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

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      A14-37 (MTT) - A12-33 (MTT) Always Below 1 Ω
      A14-37 (MTT) - Body ground Always 10 kΩ or higher
      A12-31 (GND1) - Body ground Always Below 1 Ω
      A12-32 (GND2) - Body ground Always Below 1 Ω
      for RHD
      Tester Connection Condition Specified Condition
      A14-37 (MTT) - A12-3 (MTT) Always Below 1 Ω
      A14-37 (MTT) - Body ground Always 10 kΩ or higher
      A12-1 (GND1) - Body ground Always Below 1 Ω
      A12-2 (GND2) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. READ VALUE USING GTS (ACCUMULATOR PRESSURE SENSOR)


    1. Reconnect the skid control ECU assembly connector and the brake actuator assembly connector.

    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: 2.6 to 3.8 V When brake fluid is stored in the accumulator: Accumulator pressure changes in accordance with volume of fluid stored in the accumulator

    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 0.2 V.

    NG

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    OK

  5. RECONFIRM DTC


    1. Turn the power switch off.

    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 B

    B

    REPLACE SKID CONTROL ECU ASSEMBLY Click here

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

  6. INSPECT ABS MOTOR RELAY


    1. A01FUCQE03
      Text in Illustration
      *1 ABS Motor Relay (ABS MOTOR NO. 1 or ABS MOTOR NO. 2)

      Remove the ABS motor relay (ABS MOTOR NO. 1 and ABS MOTOR NO. 2 relays).

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 - 5 Voltage is not applied between terminals 1 and 2 10 kΩ or higher
      3 - 5 Voltage is applied between terminals 1 and 2 Below 1 Ω

    NG

    REPLACE ABS MOTOR RELAY

    OK

  7. INSPECT NO. 3 ENGINE ROOM RELAY BLOCK (POWER SOURCE TERMINAL)


    1. A01FV0JE01
      Text in Illustration
      *1 No. 3 Engine Room Relay Block
      *2 ABS MOTOR NO. 1 Relay
      *3 ABS MOTOR NO. 2 Relay

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      5 (ABS MOTOR NO. 1 relay terminal) - Body ground Always 11 to 14 V
      5 (ABS MOTOR NO. 2 relay terminal) - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

  8. CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - NO. 3 ENGINE ROOM RELAY BLOCK)


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

    2. Disconnect the A12 brake actuator assembly connector.

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

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      A12-2 (BM1) - 3 (ABS MOTOR NO. 1 relay terminal) Always Below 1 Ω
      A12-2 (BM1) - Body ground Always 10 kΩ or higher
      A12-1 (BM2) - 3 (ABS MOTOR NO. 2 relay terminal) Always Below 1 Ω
      A12-1 (BM2) - Body ground Always 10 kΩ or higher
      for RHD
      Tester Connection Condition Specified Condition
      A12-31 (BM1) - 3 (ABS MOTOR NO. 1 relay terminal) Always Below 1 Ω
      A12-31 (BM1) - Body ground Always 10 kΩ or higher
      A12-32 (BM2) - 3 (ABS MOTOR NO. 2 relay terminal) Always Below 1 Ω
      A12-32 (BM2) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU ASSEMBLY - NO. 3 ENGINE ROOM RELAY BLOCK)


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

    2. Disconnect the A14 and A16 skid control ECU assembly connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A14-36 (R1-) - 2 (ABS MOTOR NO. 1 relay terminal) Always Below 1 Ω
      A14-36 (R1-) - Body ground Always 10 kΩ or higher
      A14-35 (MR1) - 1 (ABS MOTOR NO. 1 relay terminal) Always Below 1 Ω
      A14-35 (MR1) - Body ground Always 10 kΩ or higher
      A16-37 (R2-) - 2 (ABS MOTOR NO. 2 relay terminal) Always Below 1 Ω
      A16-37 (R2-) - Body ground Always 10 kΩ or higher
      A16-36 (MR2) - 1 (ABS MOTOR NO. 2 relay terminal) Always Below 1 Ω
      A16-36 (MR2) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here