Diagnostic trouble code C1252 Land Cruiser

DESCRIPTION

WIRING DIAGRAM

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 C1252/52 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
C1252/52 The motor operates for 3 minutes or more.
  1. Hydraulic brake booster pump motor
  2. Hydraulic brake booster pump motor circuit
  3. Accumulator pressure sensor

HINT:

The pump motor continues operation for the first 3 minutes, then repeats start and stop.

Wiring diagram

Diagnostic trouble code C1252 Land Cruiser. Wiring diagram

Inspection procedure

NOTICE:

When replacing the hydraulic brake booster assembly (master cylinder solenoid), perform zero point calibration .

HINT:

When C1253/53, C1254/54, or C1256/56 is output together with C1252/52, inspect and repair the trouble area indicated by C1253/53, C1254/54, or C1256/56 first.

1.CHECK PUMP MOTOR OPERATION

  1. Turn the ignition switch off.

  1. Depress the brake pedal more than 20 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 LHD B
    RHD C
    Pump motor operates intermittently D
    Pump motor operates, then stops E
  B  
REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY
 
  C  
REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY
 
  D  
Go to step 4
 
  E  
Go to step 5
 
A  
   

2.CHECK CONNECTION OF PUMP MOTOR WIRE HARNESS

  1. Remove the hydraulic brake booster assembly (LHD: /RHD: ).

  1. Using a screwdriver, remove the 2 plugs from the hydraulic brake booster assembly (LHD: /RHD: ).

  1. Check the tightening torque of the 2 screws which tighten the wire harness connecting the hydraulic brake booster assembly and brake booster pump (LHD: /RHD:).

OK:

The harness is tightened to the specific torque.

Torque:

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

  NG  
RETIGHTEN SCREWS
 
OK  
   

3.CHECK RESISTANCE OF PUMP MOTOR WIRE HARNESS

Diagnostic trouble code C1252 Land Cruiser. Using a screwdriver, remove the 2 screws and pull the wire harness from the hydraulic brake booster assembly.

  1. Using a screwdriver, remove the 2 screws and pull the wire harness from the hydraulic brake booster assembly.

  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 2 ?
    Result
    Result Proceed to
    OK A
    NG LHD B
    RHD C
  B  
REPLACE BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY
 
  C  
REPLACE BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY
 
A  
   

4.READ VALUE USING INTELLIGENT TESTER (ACCUMULATOR SENSOR)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and 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 the "Normal Condition" range A
    Output value is out of the "Normal Condition" range LHD B
    RHD C
    Output value is constant regardless of pump operation LHD D
    RHD E
  B  
REPLACE MASTER CYLINDER SOLENOID
 
  C  
REPLACE MASTER CYLINDER SOLENOID
 
  D  
REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY
 
  E  
REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY
 
A  
   

5.RECONFIRM DTC

  1. Clear the DTC .

  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 .

    HINT:

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

    Result
    Result Proceed to
    DTC is output LHD A
    RHD B
    DTC is not output LHD C
    RHD D
  B  
REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY
 
  C  
REPLACE BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY
 
  D  
REPLACE BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY
 
A  
   
REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY