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Home >> Lexus >> 2012 >> LS 460 AWD >> Repair and Diagnosis (Single Page) >> Brakes >> Anti-Lock Brakes >> Electronically Controlled Brake System (Diagnostic Codes & Symptom Tests) >> Electronically Controlled Brake System >> DTC C1252/52: Brake Booster Pump Motor on Time Abnormally Long; DTC C1253/53: Pump Motor Relay Malfunction >> Procedure

DTC C1252/52: Brake Booster Pump Motor on Time Abnormally Long; DTC C1253/53: Pump Motor Relay Malfunction: Procedure

  1. INSPECT FUSE (ABS MTR1, ABS MTR2, ABS MAIN1 AND ABS MAIN2) 
    1. Remove the ABS MTR1, ABS MTR2, ABS MAIN1 and ABS MAIN2 fuses from the engine room No. 2 relay block.
      Fig 1: Inspecting Fuse (ABS MTR1, ABS MTR2, ABS MAIN1 AND ABS MAIN2)
      GTY289317Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance of the fuses.

      Standard resistance

      Tester Connection Condition Specified Condition
      ABS MTR1 H-fuse Always Below 1 Ω
      ABS MTR2 H-fuse Always Below 1 Ω
      ABS MAIN1 Always Below 1 Ω
      ABS MAIN2 Always Below 1 Ω

    NG → REPLACE FUSE 

    OK: Go to next step 

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

      HINT: 

      • The ABS relay is a semiconductor relay. It does not emit operation sounds.
      • The ABS relay cannot be removed and inspected, as it is part of the engine room No. 2 relay block.
    4. Remove the terminal cover.
      Fig 2: Identifying Terminal Cover From Engine Room No. 2 Relay Block
      GTY110739Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      ABS/VSC/TRAC

      Tester Display Test Part Control Range Diagnostic Note
      Electronically Controlled Brake System Motor Relay Turns electronically controlled brake system motor relay ON / OFF Operation sound of relay (clicking sound) and motor can be heard
    5. Measure the voltage according to the value(s) in the table below.
      Fig 3: ABS Relay Inner Circuit Diagram
      GTY350151Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard voltage

      Tester Connection Condition Specified Condition
      Terminal 23 or 24 - Body ground Motor relay: ON 11 to 14 V
      Motor relay: OFF Below 1 V
      Terminal 25 or 26 - Body ground Always 11 to 14 V

    NG → See step   8 

    OK: Go to next step 

  3. CHECK TERMINAL VOLTAGE (BM1) 
    1. Disconnect the A23 pump connector.
    2. Read value of the Techstream (ABS MTR relay).
      1. Connect the Techstream to the DLC3.
      2. Turn the engine switch on (IG).
      3. Select the Active Test mode on the Techstream.
        ABS/VSC/TRAC

        Tester Display Test Part Control Range Diagnostic Note
        Electronically Controlled Brake System Motor Relay Turns electronically controlled brake system motor relay ON / OFF Operation sound of relay (clicking sound) and motor can be heard
    3. Measure the voltage according to the value(s) in the table below.
      Fig 4: Identifying A23 Brake Accumulator Pump Connector Terminals
      GTY127662Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard voltage

      Tester Connection Condition Specified Condition
      A23-2 (BM1) - Body ground ABS MTR relay: ON 11 to 14 V
      ABS MTR relay: OFF Below 1 V

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  4. PERFORM ACTIVE TEST USING TECHSTREAM (ABS MTR2 RELAY) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Select the Active Test mode on the Techstream.
      ABS/VSC/TRAC

      Tester Display Test Part Control Range Diagnostic Note
      Electronically Controlled Brake System Motor Relay2 Turns electronically controlled brake system motor relay 2 ON / OFF Operation sound of relay (clicking sound) and motor can be heard
    4. Check the operation sound of the ABS MTR2 relay and motor when operating it with the Techstream.

      OK

      The operation sound of the ABS MTR 2 relay and motor are heard.

    NG → See step   11 

    OK: Go to next step 

  5. INSPECT BRAKE ACCUMULATOR PUMP 
    1. Turn the engine switch off.
      Fig 5: Identifying Brake Accumulator Pump Connector Terminals
      GTY135218Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the A23 and A24 pump connectors.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Condition Specified Condition
      A-2 (BM1) - A-4 (GND1) Always 10 Ω or less
      B-2 (BM2) - A-4 (GND1)
      A-2 (BM1) - B-2 (BM2) Always Below 1 Ω
      A-4 (GND1) - B-1 (GND2)
      A-2 (BM1) - A-1 (MTT) Always 950 to 1050 Ω
      B-2 (BM2) - A-1 (MTT)

    NG → See step   19 

    OK: Go to next step 

  6. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BRAKE ACCUMULATOR PUMP) 
    1. Turn the engine switch off.
    2. Disconnect the A19 ECU connector.
    3. Disconnect the A23 and A24 pump connectors.
    4. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Condition Specified Condition
      A19-37 (MTT) - A23-1 (MTT) Always Below 1 Ω
      A19-37 (MTT) - Body ground Always 10 kΩ or higher
      A23-4 (GND1) - Body ground Always Below 1 Ω
      A24-1 (GND2) - Body ground Always Below 1 Ω

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  7. READ VALUE USING TECHSTREAM (ACCUMULATOR SENSOR) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Select the Data List mode on the Techstream.
      ABS/VSC/TRAC

      Tester Display Measurement Item /
      Range      		 Normal Condition Diagnostic Note
      Accumulator Sensor Accumulator pressure sensor / min.: 0.00 V, max.: 5.00 V Specified value: 2.60 to 3.80 V -
    4. Depress the brake pedal 4 or 5 times to operate the pump motor, and check the output value on the Techstream with the motor stopped (not braking) for 30 seconds.

      OK

      The accumulator pressure sensor voltage change is within 0.2 V.

      HINT: 

      • This inspection is performed to determine if there is a long term power malfunction when low pressure is detected in the accumulator due to a sensor malfunction, fluid leak in the actuator, or accumulator deterioration.
      • If the reservoir fluid level drops, there may be a fluid leak.

    NG → See step   16 

    OK: Go to next step 

  8. CHECK TERMINAL VOLTAGE (ENGINE ROOM NO. 2 JUNCTION BLOCK) 
    Fig 6: Identifying 2F Junction Block Connector From Engine Room No. 2 Junction Block
    GTY255270Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the 2F junction block connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage

      Tester Connection Condition Specified Condition
      2F-1 - Body ground Always 11 to 14 V

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  9. INSPECT ENGINE ROOM NO. 2 RELAY BLOCK AND NO. 2 JUNCTION BLOCK (INNER CIRCUIT) 
    Fig 7: Identifying 2B And 2F Junction Block Connectors
    GTY289351Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Turn the engine switch off.
    2. Disconnect the 2B and 2F junction block connectors.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Condition Specified Condition
      2F-1 - Terminal 25 or 26 Always Below 1 Ω
      2B-1 - Terminal 23 or 24 Always Below 1 Ω

    NG → REPLACE ENGINE ROOM NO. 2 RELAY BLOCK AND NO. 2 JUNCTION BLOCK 

    OK: Go to next step 

  10. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - ENGINE ROOM NO. 2 JUNCTION BLOCK) 
    1. Turn the engine switch off.
    2. Disconnect the A19 ECU connector.
    3. Disconnect the 2G junction block connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Condition Specified Condition
      A19-35 (MR1) - 2G-14 Always Below 1 Ω
      A19-36 (R1-) - 2G-13 Always Below 1 Ω
      A19-35 (MR1) - Body ground Always 10 kΩ or higher
      A19-36 (R1-) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → REPLACE ENGINE ROOM NO. 2 JUNCTION BLOCK 

  11. INSPECT ABS MOTOR RELAY 2 (ABS MTR2) 
    1. Remove the ABS motor relay 2 (ABS MTR2).
      Fig 8: Inspecting ABS Motor Relay (ABS MTR2)
      GTY123250Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Condition Specified Condition
      3 - 5 When battery voltage is not applied to terminals 1 and 2 10 kΩ or higher
      3 - 5 When battery voltage is applied to terminals 1 and 2 Below 1 Ω

    NG → See step   17 

    OK: Go to next step 

  12. CHECK TERMINAL VOLTAGE (NO. 3 RELAY BLOCK) 
    1. Remove the ABS motor relay 2 (ABS MTR2).
      Fig 9: Checking Terminal Voltage (No. 3 Relay Block)
      GTY347956Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage

      Tester Connection Condition Specified Condition
      ABS motor relay 2 terminal 5 (ABS MTR2) - Body ground Always 11 to 14 V

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  13. CHECK HARNESS AND CONNECTOR (BRAKE ACCUMULATOR PUMP - NO. 3 RELAY BLOCK) 
    1. Disconnect the A24 pump connector.
    2. Remove the ABS motor relay 2 (ABS MTR2).
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Condition Specified Condition
      A24-2 (BM2) - ABS motor relay 2 terminal 3 (ABS MTR2) Always Below 1 Ω
      A24-2 (BM2) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  14. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - NO. 3 RELAY BLOCK) 
    1. Disconnect the A21 ECU connector.
    2. Remove the ABS motor relay 2 (ABS MTR2).
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Condition Specified Condition
      A21-36 (MR2) - ABS motor relay 2 terminal 1 (ABS MTR2) Always Below 1 Ω
      A21-37 (R2-) - ABS motor relay 2 terminal 2 (ABS MTR2) Always Below 1 Ω
      A21-37 (R2-) - Body ground Always 10 kΩ or higher
      A21-36 (MR2) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  15. RECONFIRM DTC 
    1. Clear the DTC. Refer to DTC CHECK / CLEAR .
    2. Turn the engine switch on (IG).
    3. Check if the same DTCs are recorded. Refer to DTC CHECK / CLEAR .

      HINT: 

      Reinstall the sensors, connectors, etc. and restore the vehicle to its prior condition before rechecking for DTCs.

      RESULT

      Result Proceed to
      DTCs (C1252/52 and C1253/53) are not output A
      DTCs (C1252/52 and C1253/53) are output B

    B → See step   18 

    A → END 

  16. PERFORM ACTIVE TEST USING TECHSTREAM (SMC1, SMC2, SLRRR, AND SLRRL) 
    Fig 10: Brake Actuator Inner Diagram
    GTY124167Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream main switch on.
    4. Select the Active Test mode on the Techstream.

      HINT: 

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

      • Main relay 1 and 2 are on.
      • Shift lever is P position.
      • Parking brake is on.
      • Vehicle speed is 0 km/h (0 mph).
      ABS/VSC/TRAC

      Tester Display Test Part Control Range Diagnostic Note
      Electronically Controlled Brake System Solenoid (SMC1) Turns electronically controlled brake system solenoid (SMC1) ON / OFF Operation sound of solenoid (clicking sound) can be heard
      Electronically Controlled Brake System Solenoid (SMC2) Turns electronically controlled brake system solenoid (SMC2) ON / OFF Operation sound of solenoid (clicking sound) can be heard
      Electronically Controlled Brake System Solenoid (SLRRL) Valve Close Turns SLRRR solenoid ON / OFF Operation sound of solenoid (clicking sound) can be heard
      Electronically Controlled Brake System Solenoid (SLRRR) Valve Close Turns SLRRR solenoid ON / OFF Operation sound of solenoid (clicking sound) can be heard
    5. Using the Techstream, turn SMC1, SMC2, SLRRR, or SLRRL ON.
    6. Check that each wheel cylinder's output value does not increase.

      OK

      Each wheel cylinder's output value does not increase.

      HINT: 

      If any of wheel cylinder's output value increases, there may be a brake fluid leak in the brake actuator.

    NG → See step   20 

    OK → See step   21 

  17. REPLACE ABS MOTOR RELAY 2 (ABS MTR2). Refer to  ON-VEHICLE INSPECTION - Step 2 
  18. REPLACE SKID CONTROL ECU. Refer to  REMOVAL 
  19. REPLACE BRAKE ACCUMULATOR PUMP. Refer to  REMOVAL 
  20. REPLACE BRAKE ACTUATOR. Refer to  REMOVAL 
  21. REPLACE BRAKE ACCUMULATOR PUMP. Refer to  REMOVAL 
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