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

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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
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DESCRIPTION

The regulator pressure sensor and wheel cylinder pressure sensor are built into the brake actuator. They measure their respective pressures and send signals to the skid control ECU (brake booster with master cylinder assembly).

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 No. 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 assembly
↑ 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 brake pedal stroke sensor assembly and the readings remain out of specification for 0.5 to 5 seconds or more continuously.

    (The brake pedal stroke sensor assembly 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 assembly

  • Brake booster with master cylinder assembly
↑ 207

Fluctuation of regulator pressure sensor output is out of specification (the difference between the present value and last value is 15 MPa (153.0 kgf/cm2, 2176 psi) or more) for 0.1 seconds or more.

 Brake booster with master cylinder assembly
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 assembly
↑ 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 (153.0 kgf/cm2, 2176 psi) or more) for 0.1 seconds or more.

 ↑
C1281/81 - Detected only during Test Mode.

  • Stop light switch assembly

  • Regulator pressure sensor (Brake booster with master cylinder assembly)
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CAUTION / NOTICE / HINT

Note:

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

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PROCEDURE


  1. Click here

    CHECK STOP LIGHT SWITCH ASSEMBLY INSTALLATION


    1. Check the protrusion of the rod (Click here).

      OK
      Stop light switch assembly is installed properly.
      Tip:

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


  2. Click here

    READ VALUE USING GTS (REGULATOR PRESSURE SENSOR)


    1. Mount a pedal effort gauge and install LSPV gauges to the rear wheels (Click here).

    2. Connect the GTS to the DLC3.

    3. Turn the power switch on (IG).

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

      Table 1. ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Regulator Pressure Sensor Output Regulator pressure sensor output / Min.: 0.00 V, Max.: 5.00 V

      When brake pedal released:

      0.10 to 0.90 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) 1.32 to 2.12 3.98 to 7.98 (40.6 to 81.3, 578 to 1157) 3.98 to 7.98 (40.6 to 81.3, 578 to 1157)
      200 (20, 45.0) 2.90 to 3.70 11.72 to 15.72 (119.6 to 160.2, 1700 to 2280) 11.72 to 15.72 (119.6 to 160.2, 1700 to 2280)

  3. Click here

    READ VALUE USING GTS (WHEEL CYLINDER PRESSURE SENSOR)


    1. Install LSPV gauges to the front wheels (Click here).

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

      Table 2. ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Wheel Cylinder Pressure Sensor Wheel cylinder pressure sensor / Min.: 0.00 V, Max.: 5.00 V

      When brake pedal released:

      0.10 to 0.90 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 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 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

  4. Click here

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


    1. Mount a pedal effort gauge and install LSPV gauges to the front and rear wheels (Click here).

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

      Table 3. ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Stroke Sensor Brake pedal stroke sensor assembly / Min.: 0.00 V, Max.: 5.00 V When brake pedal released: 0.65 to 1.35 V Reading increases when brake pedal is depressed
      Stroke Sensor2 Brake pedal stroke sensor assembly 2 / Min.: 0.00 V, Max.: 5.00 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.: 0.00 V, Max.: 5.00 V

      When brake pedal released:

      0.10 to 0.90 V

      		 Reading increases when brake pedal is depressed
      Wheel Cylinder Pressure Sensor Wheel cylinder pressure sensor / Min.: 0.00 V, Max.: 5.00 V

      When brake pedal released:

      0.10 to 0.90 V

      		 Reading increases when brake pedal is depressed

    3. Check the output value of the brake pedal stroke sensor assembly 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) 1.65 to 2.35 2.65 to 3.35 1.32 to 2.12 1.14 to 1.94
      200 (20, 45.0) 2.38 to 3.08 1.92 to 2.62 2.90 to 3.70 2.49 to 3.29

  5. Click here

    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 output (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. B

    • A

      USE SIMULATION METHOD TO CHECK (Click here)

    • B

      REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (Click here)