VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C1252

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

DESCRIPTION

The motor relay (semiconductor relay) is built into the master cylinder solenoid and drives the pump motor based on a signal from the skid control ECU.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1252

Brake Booster Pump Motor on Time Abnormally Long

The motor operates for 3 minutes or more.

  • Brake booster with accumulator pump assembly

  • Pump motor wire harness condition

  • Master cylinder solenoid (Skid control ECU)

  • Hydraulic brake booster assembly
Tip:

The pump motor continues operation for the first 3 minutes, and then starts and stops repeatedly.

CAUTION / NOTICE / HINT

Note:

When replacing the master cylinder solenoid, perform calibration (Click here).

Tip:

When DTC C1253, C1254, C1256 or C1452 is output together with DTC C1252, inspect and repair the trouble area indicated by DTC C1253, C1254, C1256 or C1452 first.

PROCEDURE

  1. CHECK PUMP MOTOR OPERATION

    1. Turn the engine switch off.

    2. Depress the brake pedal more than 40 times.

    3. Turn the engine switch on (IG).

    4. Check how the pump motor operates.

      Result

      Result

      Proceed to

      Pump motor does not operate

      A

      Pump motor operates continuously and does not stop

      B

      Pump motor operates intermittently

      C

      Pump motor operates, and then stops

      D
    B

    REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY

    Click here

    C

    READ VALUE USING INTELLIGENT TESTER (ACCUMULATOR SENSOR)Click here

    D

    RECONFIRM DTCClick here

    A

  2. CHECK CONNECTION OF PUMP MOTOR WIRE HARNESS

    1. Remove the hydraulic brake booster assembly.

      Click here

    2. Check the tightening torque of the 2 screws which secure the wire harness connecting the master cylinder solenoid and brake booster with accumulator pump assembly.

      Click here

      OK

      The harness is tightened to the specified torque.

      Torque

      2.9 N*m{ 30 kgf*cm , 26 in.*lbf }

      Result

      Result

      OK

      NG
    NG

    RETIGHTEN SCREWS

    OK

  3. CHECK RESISTANCE OF PUMP MOTOR WIRE HARNESS

    1. Using a screwdriver, remove the 2 screws and pull out the wire harness from the master cylinder solenoid.

    2. C173363C02

      *1

      Pump motor wire harness

      *a

      Red wire

      *b

      Black wire

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      Red wire terminal - Black wire terminal

      Always

      Below 2 Ω

      Result

      Result

      OK

      NG
    NG

    REPLACE BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY

    Click here

    OK

  4. READ VALUE USING INTELLIGENT TESTER (ACCUMULATOR SENSOR)

    1. Turn the engine switch off.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the engine switch on (IG).

    4. Turn the intelligent tester on.

    5. Enter the following menus: Chassis / ABS/VSC/TRC / Data List.

      Chassis > ABS/VSC/TRC > Data List

      Tester Display

      Measurement Item

      Range

      Normal Condition

      Diagnostic Note

      Accumulator Sensor

      Accumulator pressure sensor reading

      Min.: 0.00 V, Max.: 5.00 V

      3.58 to 5 V

      If the value is constant regardless of the pump operation, an accumulator pressure sensor malfunction is suspected.

    6. Check the accumulator output value.

      Result

      Result

      Proceed to

      Output value is within "Normal Condition" range

      A

      Output value is out of "Normal Condition" range

      B

      Output value is constant regardless of pump operation

      C
    B

    REPLACE MASTER CYLINDER SOLENOID

    Click here

    C

    REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY

    Click here

    A

  5. RECONFIRM DTC

    1. Clear the DTCs.

      Click here

      Chassis > ABS/VSC/TRC > Clear DTCs

    2. Turn the engine switch off.

    3. Turn the engine switch on (IG).

    4. Wait for more than 5 minutes.

    5. Check if the same DTC is output.

      Click here

      Result

      Result

      Proceed to

      DTC is output

      A

      DTC is not output

      B
      Tip:

      Reinstall the sensors, reconnect the connectors, etc. and restore the previous vehicle conditions before rechecking for DTCs.

      Chassis > ABS/VSC/TRC > Trouble Codes

    A

    REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY

    Click here

    B

    REPLACE BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY

    Click here