Dtc C1252 Brake Booster Pump Motor On Time Abnormally Long


DESCRIPTION

INSPECTION PROCEDURE

CHECK PUMP MOTOR OPERATION

CHECK CONNECTION OF PUMP MOTOR WIRE HARNESS

CHECK RESISTANCE OF PUMP MOTOR WIRE HARNESS

READ VALUE USING INTELLIGENT TESTER (ACCUMULATOR SENSOR)

RECONFIRM DTC

DTC 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 Code
DTC Detection Condition
Trouble Area
C1252
The motor operates for 3 minutes or more.
  1. Brake booster with accumulator pump assembly
  2. Pump motor wire harness condition
  3. Master cylinder solenoid (Skid control ECU)
  4. Hydraulic brake booster assembly
HINT:
The pump motor continues operation for the first 3 minutes, and then starts and stops repeatedly.

INSPECTION PROCEDURE

NOTICE:
When replacing the master cylinder solenoid, perform calibration (LandCruiser RM00000452J00ZX.html).
HINT:
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.
1.CHECK PUMP MOTOR OPERATION

  1. Turn the ignition switch off.

  1. Depress the brake pedal more than 40 times.

  1. Turn the ignition switch to ON.

  1. 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
HINT:
Refer to the hydraulic brake booster assembly installation procedures:
  1. for LHD (LandCruiser RM00000171T033X.html)
  2. for RHD (LandCruiser RM00000171T034X.html)


B
REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY

C
Go to step 4

D
Go to step 5
A


2.CHECK CONNECTION OF PUMP MOTOR WIRE HARNESS

  1. Remove the hydraulic brake booster assembly (for LHD: LandCruiser RM00000171T033X.html, for RHD: LandCruiser RM00000171T034X.html).

  1. 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 (for LHD: LandCruiser RM00000171V02GX.html, for RHD: LandCruiser RM00000171V02HX.html).

OK:
The harness is tightened to the specified torque.
Torque:
2.9 N*m{30 kgf*cm, 26 in.*lbf}


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.



    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Brake Control Dynamic Control Systems.Anti-Lock Brake System. Dtc C1252 Brake Booster Pump Motor On Time Abnormally Long

  1. 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
    Text in Illustration
    *1
    		Pump motor wire harness
    *a
    		Red wire
    *b
    		Black wire
HINT:
Refer to the brake booster with accumulator pump assembly installation procedures:
for LHD (LandCruiser RM00000171U02DX.html)
for RHD (LandCruiser RM00000171U02EX.html)


NG
REPLACE BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY
OK


4.READ VALUE USING INTELLIGENT TESTER (ACCUMULATOR SENSOR)

  1. Turn the ignition switch off.

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the intelligent tester on.

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

    ABS/VSC/TRC
    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.

  1. 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
HINT:
  1. Refer to the hydraulic brake booster assembly installation procedures:
    for LHD (LandCruiser RM00000171T033X.html)
    for RHD (LandCruiser RM00000171T034X.html)
  2. Refer to the master cylinder solenoid installation procedures:
    for LHD (LandCruiser RM00000171U02DX.html)
    for RHD (LandCruiser RM00000171U02EX.html)


B
REPLACE MASTER CYLINDER SOLENOID

C
REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY
A


5.RECONFIRM DTC

  1. Clear the DTCs (LandCruiser RM0000046KV016X.html).

  1. Turn the ignition switch off.

  1. Turn the ignition switch to ON.

  1. Wait for more than 5 minutes.

  1. Check if the same DTC is output (LandCruiser RM0000046KV016X.html).

    Result
    Result
    		Proceed to
    DTC is output
    		A
    DTC is not output
    		B
    HINT:
    1. Reinstall the sensors, reconnect the connectors, etc. and restore the previous vehicle conditions before rechecking for DTCs.
    2. Refer to the hydraulic brake booster assembly installation procedures:
      for LHD (LandCruiser RM00000171T033X.html)
      for RHD (LandCruiser RM00000171T034X.html)
    3. Refer to the brake booster with accumulator pump assembly installation procedures:
      for LHD (LandCruiser RM00000171U02DX.html)
      for RHD (LandCruiser RM00000171U02EX.html)


B
REPLACE BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY
A

REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY