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Home >> Toyota >> 2008 >> FJ Cruiser RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 146 (Brakes - Abs With VSC) >> Vehicle Stability Control System >> DTC C1252/52 Brake Booster Pump Motor on Time Abnormally Long >> Inspection Procedure

Inspection Procedure

WARNING: This page is about a different car, the 2007 Toyota Land Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK OPERATION OF BRAKE ACTUATOR PUMP MOTOR 
    1. Disconnect the A37 and A38 actuator connectors.
    2. Connect the battery positive (+) lead to terminal 2 (BM1) or 3 (BM2) and battery negative (-) lead to terminal 1 (GND1) or 6 (GND2) of the brake actuator (pump motor).

    OK: Operation sound of pump motor should be heard. 

    OK: GO TO step   10

    Fig 1: Identifying A37 And A38 Actuator Connectors
    G05197639Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: GO TO Next Step 

  2. CHECK WIRE HARNESS (BRAKE ACTUATOR - ABS MTR 1 RELAY AND ABS MTR 2 RELAY) 

    NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

    OK: GO TO Next Step 

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

    NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

    OK: GO TO Next Step 

  4. READ DATA LIST (PRESS SWITCH (PH) AND (PL)) 
    1. Check the DATA LIST for proper functioning of the hydraulic brake boost pressure switch (PH) and (PL).
    2. Depress the brake pedal more than 40 times with the ignition switch OFF. Then turn the ignition switch ON and check the pressure switch (PH) and (PL) condition.

    Skid control ECU assembly: 

    DATA LIST REFERENCE

    Item Measurement Item/Range (Display) Normal Condition Diagnostic Note
    PRESS HIGH HIGH Hydraulic brake boost pressure/ ON or OFF - -
    PRESS LOW LOW Hydraulic brake boost pressure/ ON or OFF - -

    HINT:

    When pressure in power supply system is released, reaction force becomes light.

    OK: "OFF" turns to "ON" 

    OK: REPLACE SKID CONTROL ECU ASSEMBLY 

    NG: GO TO Next Step 

  5. CHECK BRAKE BOOSTER PRESSURE SWITCH (PH) 
    1. Disconnect the A37 actuator connector.
    2. With the ignition switch OFF, depress the brake pedal more than 40 times to decrease the accumulator pressure.

      HINT:

      When pressure in power supply system is released, reaction force becomes light.

    3. Measure the resistance between terminal 3 (PH) and 5 (PHG) of the brake actuator connector.

      Standard resistance: 

      0.9 to 1.1 kΩ 

    4. Connect the A37 actuator connector.
    5. Disconnect the A37 actuator connector after the ignition switch has been ON and the pump motor has stopped.
    6. Measure the resistance between terminal 3 (PH) and 5 (PHG) of the brake actuator.

    Standard resistance: 

    Below 1 Ω 

    Fig 2: Identifying A37 Actuator Connector Terminals
    G05197643Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    HINT:

    After inspection, connect the connector and clear the DTC.

    NG: REPLACE BRAKE ACTUATOR 

    OK: GO TO Next Step 

  6. CHECK BRAKE BOOSTER PRESSURE SWITCH (PL) 
    1. Disconnect the A38 actuator connector.
    2. With the ignition switch OFF, depress the brake pedal more than 40 times to decrease the accumulator pressure.

      HINT:

      When pressure in power supply system is released, reaction force becomes light.

    3. Measure the resistance between terminal 4 (PL) and 2 (PLG) of the brake actuator connector.

      Standard resistance: 

      5.1 to 6.3 kΩ 

    4. Connect the A38 actuator connector.
    5. Disconnect the A38 actuator connector after the ignition switch has been ON and the pump motor has stopped.
    6. Measure the resistance between terminal 4 (PL) and 2 (PLG) of the brake actuator.

    Standard resistance: 

    1.0 kΩ 

    HINT:

    After inspection, connect the connector and clear the DTC.

    Fig 3: Identifying A38 Actuator Connector Terminals
    G05197644Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE BRAKE ACTUATOR 

    OK: GO TO Next Step 

  7. CHECK WIRE HARNESS (SKID CONTROL ECU ASSEMBLY - BRAKE ACTUATOR (PRESSURE SWITCH)) 

    NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

    OK: GO TO Next Step 

  8. INSPECT RELAY (Marking: ABS MTR 1, ABS MTR 2) 
    1. Remove the ABS MTR 1 and ABS MTR 2 from the engine room relay block.
    2. Measure the resistance of the relay.

    Standard resistance 

    STANDARD RESISTANCE REFERENCE CHART

    Tester Connection Specified Condition
    1 - 2 10 kΩ or higher
    1 - 2 Below 1 Ω (When battery voltage is applied to terminals 3 and 4)

    NG: REPLACE RELAY 

    Fig 4: Identifying Relay Connector Terminals
    G05197645Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: GO TO Next Step 

  9. CHECK WIRE HARNESS (SKID CONTROL ECU ASSEMBLY - ABS MTR 1 RELAY AND ABS MTR 2 RELAY) 

    NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

    OK: REPLACE SKID CONTROL ECU ASSEMBLY 

  10. CHECK WIRE HARNESS (SKID CONTROL ECU ASSEMBLY - BRAKE ACTUATOR) 

    NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

    OK: GO TO Next Step 

  11. CHECK BRAKE ACTUATOR PUMP MOTOR 
    1. Check the brake actuator pump motor (see REMOVAL ).

    NG: REPLACE BRAKE ACTUATOR PUMP MOTOR 

    OK: REPLACE BRAKE ACTUATOR 

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