ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1246/46, C1281/81, C1364/61

DTC Code DTC Name
C1246/46 Master Cylinder Pressure Sensor Malfunction
C1281/81 Master Cylinder Pressure Sensor Output Malfunction (Test Mode DTC)
C1364/61 Wheel Cylinder Pressure Sensor Malfunction

DESCRIPTION

The regulator pressure sensor and the wheel cylinder pressure sensor are built into the brake actuator, and measure the regulator pressure and the wheel cylinder pressure sent to the skid control ECU.

DTC C1281/81 will be cleared when the regulator pressure sensor sends a regulator pressure signal or when Test Mode ends. DTC C1281/81 is output only in Test Mode.

DTC Code INF Code DTC Detection Condition Trouble Area
C1246/46 201 Sensor supply voltage (VCM1) is 4.75 V or less, or 5.25 V or more for 0.05 seconds. Brake booster with master cylinder (Skid control ECU or brake actuator)
↑ 202 Regulator pressure sensor output voltage (Preg) is less than 8%, or 90.3% or more (less than 0.4 V, or 4.52 V or more) of sensor supply voltage (VCM1) for 0.05 seconds or more. ↑
↑ 203 When not under braking, the regulator pressure sensor output voltage is 0.2 V or less or 0.88 V or more for 3 seconds or more. ↑
↑ 204

Either of the following is detected:


  1. The regulator pressure sensor output voltage does not correspond with stroke sensor and the readings remain out of specification for 0.5 to 5 seconds or more continuously.

    (The stroke sensor may be malfunctioning.)

  2. The regulator pressure sensor output voltage does not correspond with wheel cylinder pressure sensor and the outputs remain out of specification for 0.5 to 5 seconds or more continuously.

    (May be output with INF code 424.)

  • Brake pedal stroke sensor

  • Brake booster with master cylinder (Skid control ECU or brake actuator)
↑ 207 Fluctuation of regulator pressure sensor output is out of specification (the difference between the present value and last value is 15 MPa or more) for 0.1 seconds or more. Brake booster with master cylinder (Skid control ECU or brake actuator)
C1364/61 421 Sensor supply voltage 1 (VCM1) is 4.75 V or less, or 5.25 V or more for 0.05 seconds or more. Brake booster with master cylinder (Skid control ECU or brake actuator)
↑ 422 Wheel cylinder pressure sensor output voltage (Pfront) is less than 8%, or 90.3% or more (less than 0.4 V, or 4.52 V or more) of sensor supply voltage (VCM1) for 0.05 seconds or more. ↑
↑ 423 When not under braking, the wheel cylinder pressure sensor output voltage is 0.2 V or less or 0.88 V or more for 0.1 to 3 seconds or more. ↑
↑ 424

The wheel cylinder pressure sensor output voltage does not correspond with regulator pressure sensor and the outputs remain out of specification for 0.5 to 5 seconds or more continuously.

(May be output with INF code 204.)

 ↑
↑ 426 Fluctuation of wheel cylinder pressure sensor output is out of specification (the difference between the present value and last value is 15 MPa or more) for 0.1 seconds or more. ↑
C1281/81 - Detected only during Test Mode.

  • Stop light switch

  • Regulator pressure sensor

INSPECTION PROCEDURE

Note

When replacing the brake booster with master cylinder (skid control ECU or brake actuator), perform initialization, calibration of the linear solenoid valve and emergency brake signal learning Click here.

PROCEDURE


  1. CHECK STOP LIGHT SWITCH INSTALLATION


    1. Check the protrusion of the rod Click here.

      OK
      Stop light switch is installed properly.

      Tech Tips

      If the stop light switch is not installed properly, adjust the protrusion of the rod before proceeding to the next step.


    NG

    ADJUST PROTRUSION OF ROD Click here

    OK

  2. READ VALUE USING GTS (REGULATOR PRESSURE SENSOR)


    1. Set a pedal effort gauge and LSPV gauge to rear wheel Click here.

    2. Connect the in GTS to the DLC3.

    3. Turn the power switch on (IG).

    4. Select the Data List on the GTS Click here.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Regulator Pressure Sensor Output Regulator pressure sensor output / Min.: 0 V, Max.: 5 V

      When brake pedal released:

      0.1 to 0.9 V

      		 Reading increases when brake pedal is depressed

    5. Check the output value of the regulator pressure sensor as the brake pedal is depressed.

      Standard Voltage

      Brake Effort

      (N (kgf, lbf))

      Regulator Pressure Sensor Output

      (V)

      Rear Right Wheel Hydraulic Pressure

      (MPa (kgf/cm2, psi))

      Rear Left Wheel Hydraulic Pressure

      (MPa (kgf/cm2, psi))
      100 (10, 22.5) 1.48 to 2.28 4.8 to 8.8 (49.0 to 89.7, 697 to 1276) 4.8 to 8.8 (49.0 to 89.7, 697 to 1276)
      200 (20, 45.0) 3.30 to 4.10 13.8 to 17.8 (140.8 to 181.5, 2002 to 2581) 13.8 to 17.8 (140.8 to 181.5, 2002 to 2581)
      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

    C

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

    A

  3. READ VALUE USING GTS (WHEEL CYLINDER PRESSURE SENSOR)


    1. Set a LSPV gauge to front wheel Click here.

    2. Select the Data List on the GTS Click here.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Wheel Cylinder Pressure Sensor Wheel cylinder pressure sensor / Min.: 0 V, Max.: 5 V

      When brake pedal released:

      0.1 to 0.9 V

      		 Reading increases when brake pedal is depressed

    3. Check the output value of the wheel cylinder pressure sensor at each hydraulic pressure during electronically controlled brake system control.

      Standard Voltage
      for Front Wheel Cylinder Pressure Sensor LH

      Hydraulic Pressure

      (MPa (kgf/cm2, psi))

      Wheel Cylinder Pressure Sensor

      (V)
      2.0 (20.4, 290) 0.53 to 1.33
      5.0 (51.0, 725) 1.12 to 1.92
      7.0 (71.4, 1015) 1.52 to 2.32
      10.0 (102.0, 1451) 2.14 to 2.94
      for Front Wheel Cylinder Pressure Sensor RH

      Hydraulic Pressure

      (MPa (kgf/cm2, psi))

      Wheel Cylinder Pressure Sensor

      (V)
      2.0 (20.4, 290) 0.53 to 1.33
      5.0 (51.0, 725) 1.12 to 1.92
      7.0 (71.4, 1015) 1.52 to 2.32
      10.0 (102.0, 1451) 2.14 to 2.94
      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

    C

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

    A

  4. READ VALUE USING GTS (BRAKE PEDAL STROKE SENSOR AND PRESSURE SENSOR COMPARISON)


    1. Set a pedal effort gauge and LSPV gauge to front and rear wheel Click here.

    2. Select the Data List on the GTS Click here.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Stroke Sensor Brake pedal stroke sensor / Min.: 0 V, Max.: 5 V When brake pedal released: 0.65 to 1.35 V Reading increases when brake pedal is depressed
      Stroke Sensor2 Brake pedal stroke sensor 2 / Min.: 0 V, Max.: 5 V When brake pedal released: 3.65 to 4.35 V Reading decreases when brake pedal is depressed
      Regulator Pressure Sensor Output Regulator pressure sensor output / Min.: 0 V, Max.: 5 V

      When brake pedal released:

      0.1 to 0.9 V

      		 Reading increases when brake pedal is depressed
      Wheel Cylinder Pressure Sensor Wheel cylinder pressure sensor / Min.: 0 V, Max.: 5 V

      When brake pedal released:

      0.1 to 0.9 V

      		 Reading increases when brake pedal is depressed

    3. Check the output value of the brake pedal stroke sensor as the brake pedal is depressed.

      Standard Voltage

      Brake Effort

      (N (kgf, lbf))

      Stroke Sensor

      (V)

      Stroke Sensor2

      (V)

      Regulator Pressure Sensor Output

      (V)

      Wheel Cylinder Pressure Sensor

      (V)
      100 (10, 22.5) 1.07 to 1.77 3.23 to 3.93 1.48 to 2.28 1.28 to 2.08
      200 (20, 45.0) 1.45 to 2.15 2.85 to 3.55 3.30 to 4.10 2.85 to 3.65
      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    B

    REPLACE BRAKE PEDAL STROKE SENSOR Click here

    C

    REPLACE BRAKE PEDAL STROKE SENSOR Click here

    A

  5. RECONFIRM DTC


    1. Turn the power switch off.

    2. Clear the DTCs Click here.

    3. Perform a road test.

    4. Check if the same DTC is recorded Click here.

      Result
      Result Proceed to
      DTCs (C1246/46 and C1364/61) are not output A
      DTCs (C1246/46 and/or C1364/61) are output (for LHD) B
      DTCs (C1246/46 and/or C1364/61) are output (for RHD) C

    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

    C

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here