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

DTC C1281/81 will be cleared when the master cylinder pressure sensor sends a master cylinder 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
C1246/46 191 Sensor power source 1 (VCM) voltage is 4.7 V or less or 5.3 V or more for at least 0.05 seconds.

  • Brake actuator assembly (Master cylinder pressure sensor)

  • Master cylinder pressure sensor circuit

  • Master cylinder pressure sensor power supply

  • Brake actuator assembly

  • Skid control ECU
↑ 192 Master cylinder pressure sensor output voltage 1 (PMC1) is less than 0.25 V or 4.53 V or more for at least 0.05 seconds.

  • Brake actuator assembly (Master cylinder pressure sensor)

  • Master cylinder pressure sensor circuit

  • Brake actuator assembly

  • Skid control ECU
↑ 194 Sensor power source 2 (VCM2) voltage is 4.7 V or less or 5.3 V or more for at least 0.05 seconds.

  • Brake actuator assembly (Master cylinder pressure sensor)

  • Master cylinder pressure sensor circuit

  • Master cylinder pressure sensor power supply

  • Brake actuator assembly

  • Skid control ECU
↑ 195 Master cylinder pressure sensor output voltage 2 (PMC2) is less than 0.25 V or 4.53 V or more for at least 0.05 seconds.

  • Brake actuator assembly (Master cylinder pressure sensor)

  • Master cylinder pressure sensor circuit

  • Brake actuator assembly

  • Skid control ECU
↑ 197 Master cylinder pressure sensor output voltage 1 (PMC1) is abnormal.

  • Brake actuator assembly

  • Skid control ECU
↑ 198 Master cylinder pressure sensor output voltage 2 (PMC2) is abnormal. ↑
↑ 199 Master cylinder pressure sensor output voltage 1 (PMC1) is less than 0.33 V or 0.85 V or more when not braking.

  • Brake actuator assembly (Master cylinder pressure sensor)

  • Master cylinder pressure sensor circuit

  • Brake actuator assembly

  • Skid control ECU
↑ 200 Master cylinder pressure sensor output voltage 2 (PMC2) is less than 0.33 V or 0.85 V or more when not braking. ↑
↑ 201

Either of the following is detected:


  1. PMC1 and PMC2 voltages are different when braking.

  2. Master cylinder pressure sensor has a fluctuation of 15 MPa or more continuously for 0.054 seconds within a 0.6 second interval.

 ↑
↑ 202 Condition that output voltage of front wheel cylinder pressure sensor RH (PFR) and rear wheel cylinder pressure sensor LH (PRL) is less than 0.25 V or 4.53 V or more continues for 0.05 seconds or more.

  • Master cylinder pressure sensor power supply

  • Brake actuator assembly

  • Skid control ECU
↑ 205 Condition that output voltage of front wheel cylinder pressure sensor LH (PFL) is less than 0.25 V or 4.53 V or more and rear wheel cylinder pressure sensor RH (PRR) is 0.25 V or more or 4.53 V or more continues for 0.05 seconds or more. ↑
C1364/61 221 Sensor power source 1 (VCM) voltage is 4.7 V or less or 5.3 V or more for at least 0.05 seconds.

  • Wheel cylinder pressure sensor power supply

  • Brake actuator assembly

  • Skid control ECU
↑ 222 Front wheel cylinder pressure sensor RH output voltage (PFR) is 0.25 V or less or 4.53 V or more for at least 0.05 seconds.

  • Brake actuator assembly (Wheel cylinder pressure sensor)

  • Wheel cylinder pressure sensor circuit

  • Brake actuator assembly

  • Skid control ECU
↑ 224

Either of the following is detected:


  1. Front wheel cylinder pressure sensor RH output (PFR) is 0.33 V or less or 0.85 V or more for least 3 seconds when not braking.

  2. Front wheel cylinder pressure sensor RH output (PFR) is 0.33 V or less for at least 0.1 seconds when braking.

 ↑
↑ 225 The front wheel cylinder pressure sensor RH output (PFR) output voltage is stuck at 4.53 V or less. ↑
↑ 227 Sensor power source 2 (VCM2) voltage is 4.7 V or less or 5.3 V or more for at least 0.05 seconds.

  • Wheel cylinder pressure sensor power supply

  • Brake actuator assembly

  • Skid control ECU
↑ 228 Front wheel cylinder pressure sensor LH output voltage (PFL) is 0.25 V or less or 4.53 V or more for at least 0.05 seconds.

  • Brake actuator assembly (Wheel cylinder pressure sensor)

  • Wheel cylinder pressure sensor circuit

  • Brake actuator assembly

  • Skid control ECU
↑ 230

Either of the following is detected:


  1. Front wheel cylinder pressure sensor LH output (PFL) is 0.33 V or less or 0.85 V or more for least 3 seconds when not braking.

  2. Front wheel cylinder pressure sensor LH output (PFL) is 0.33 V or less for at least 0.1 seconds when braking.

 ↑
↑ 231 The front wheel cylinder pressure sensor LH output (PFL) output voltage is stuck at 4.53 V or less. ↑
↑ 233 Sensor power source 2 (VCM2) voltage is 4.7 V or less or 5.3 V or more for at least 0.05 seconds.

  • Wheel cylinder pressure sensor power supply

  • Brake actuator assembly

  • Skid control ECU
↑ 234 Rear wheel cylinder pressure sensor RH output voltage (PRR) is 0.25 V or less or 4.53 V or more for at least 0.05 seconds.

  • Brake actuator assembly (Wheel cylinder pressure sensor)

  • Wheel cylinder pressure sensor circuit

  • Brake actuator assembly

  • Skid control ECU
↑ 236

Either of the following is detected:


  1. Rear wheel cylinder pressure sensor RH output (PRR) is 0.33 V or less or 0.85 V or more for at least 3 seconds when not braking.

  2. Rear wheel cylinder pressure sensor RH output (PRR) is 0.33 V or less for at least 0.1 seconds when braking.

 ↑
↑ 237 The rear wheel cylinder pressure sensor RH output (PRR) output voltage is stuck at 4.53 V or less. ↑
↑ 239 Sensor power source 1 (VCM) voltage is 4.7 V or less or 5.3 V or more for at least 0.05 seconds.

  • Wheel cylinder pressure sensor power supply

  • Brake actuator assembly

  • Skid control ECU
↑ 240 Rear wheel cylinder pressure sensor LH output voltage (PRL) is 0.25 V or less or 4.53 V or more for at least 0.05 seconds.

  • Brake actuator assembly (Wheel cylinder pressure sensor)

  • Wheel cylinder pressure sensor circuit

  • Brake actuator assembly

  • Skid control ECU
↑ 242

Either of the following is detected:


  1. Rear wheel cylinder pressure sensor LH output (PRL) is 0.33 V or less or 0.85 V or more for at least 3 seconds when not braking.

  2. Rear wheel cylinder pressure sensor LH output (PRL) is 0.33 V or less for at least 0.1 seconds when braking.

 ↑
↑ 243 The rear wheel cylinder pressure sensor LH output (PRL) output voltage is stuck at 4.53 V or less. ↑
C1281/81 - Detected only during Test Mode.

  • Stop light switch

  • Master cylinder pressure sensor

WIRING DIAGRAM

A01NF4HE04

INSPECTION PROCEDURE

Note

When replacing the skid control ECU or brake actuator assembly, perform initialization and calibration of the linear solenoid valve Click here.

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BRAKE ACTUATOR)


    1. Make sure that there is no looseness at the locking part and the connecting part of the connectors.

      A01NEREE07
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Skid Control ECU)

      		 *2

      Front view of wire harness connector

      (to Brake Actuator)

    2. Disconnect the skid control ECU connectors and the brake actuator connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A89-9 (VCM) - A82-35 (VCM) Always Below 1 Ω
      A89-9 (VCM) - Body ground Always 10 kΩ or higher
      A89-21 (PAC1) - A82-46 (PAC1) Always Below 1 Ω
      A89-21 (PAC1) - Body ground Always 10 kΩ or higher
      A89-30 (PMC1) - A82-38 (PMC1) Always Below 1 Ω
      A89-30 (PMC1) - Body ground Always 10 kΩ or higher
      A89-32 (PFR) - A82-34 (PFR) Always Below 1 Ω
      A89-32 (PFR) - Body ground Always 10 kΩ or higher
      A89-18 (PRL) - A82-36 (PRL) Always Below 1 Ω
      A89-18 (PRL) - Body ground Always 10 kΩ or higher
      A89-8 (E) - A82-45 (E) Always Below 1 Ω
      A89-8 (E) - Body ground Always 10 kΩ or higher
      A89-31 (PCK1) - A82-37 (PCK1) Always Below 1 Ω
      A89-31 (PCK1) - Body ground Always 10 kΩ or higher
      A92-16 (VCM2) - A82-40 (VCM2) Always Below 1 Ω
      A92-16 (VCM2) - Body ground Always 10 kΩ or higher
      A92-28 (PMC2) - A82-43 (PMC2) Always Below 1 Ω
      A92-28 (PMC2) - Body ground Always 10 kΩ or higher
      A92-23 (PFL) - A82-39 (PFL) Always Below 1 Ω
      A92-23 (PFL) - Body ground Always 10 kΩ or higher
      A92-24 (PRR) - A82-41 (PRR) Always Below 1 Ω
      A92-24 (PRR) - Body ground Always 10 kΩ or higher
      A92-15 (E2) - A82-44 (E2) Always Below 1 Ω
      A92-15 (E2) - Body ground Always 10 kΩ or higher
      A92-29 (PCK2) - A82-42 (PCK2) Always Below 1 Ω
      A92-29 (PCK2) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. INSPECT SKID CONTROL ECU (SENSOR OUTPUT)


    1. A01NDO9E24
      Text in Illustration
      *1

      Component without harness connected

      (Skid Control ECU)

      Reconnect the skid control ECU connectors and the brake actuator connector.

    2. Turn the power switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A89-9 (VCM) - Body ground Power switch on (IG) 4.75 to 5.25 V
      A92-16 (VCM2) - Body ground Power switch on (IG) 4.75 to 5.25 V

    4. Turn the power switch off.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A89-8 (E) - Body ground Always Below 1 Ω
      A92-15 (E2) - Body ground Always Below 1 Ω

    NG

    REPLACE SKID CONTROL ECU Click here

    OK

  3. READ VALUE USING INTELLIGENT TESTER (MASTER CYLINDER PRESSURE SENSOR)


    1. Connect a pedal effort gauge Click here.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the power switch on (IG).

    4. Select the Data List on the intelligent tester Click here.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Master Cylinder Sensor Master cylinder pressure sensor 1 / Min.: 0 V, Max.: 5 V

      When brake pedal is released:

      0.3 to 0.7 V

      		 Reading increases when brake pedal is depressed
      Master Cylinder Sensor2 Master cylinder pressure sensor 2 / Min.: 0 V, Max.: 5 V

      When brake pedal is released:

      0.3 to 0.7 V

      		 Reading increases when brake pedal is depressed

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

      Tech Tips


      • Check the value while electronically controlled brake system control is disabled and without servo assistance.

      • The brake warning light / yellow (minor malfunction) is on while electronically controlled brake system control is being disabled.

      Standard Voltage
      Brake Effort N (kgf, lbf)

      Master Cylinder Sensor

      (Data List Display)

      Master Cylinder Sensor2

      (Data List Display)
      200 (20, 45.0) 0.90 to 1.30 V 0.90 to 1.30 V
      500 (51, 112.4) 2.10 to 2.50 V 2.10 to 2.50 V

    NG

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    OK

  4. READ VALUE USING INTELLIGENT TESTER (WHEEL CYLINDER PRESSURE SENSOR)


    1. Turn the power switch off.

    2. Install a hydro LSPV gauge and bleed air Click here.

      SST
      09709-29018

    3. Turn the power switch on (IG).

    4. Select the Data List on the intelligent tester Click here.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      FR W/C Sensor FR wheel cylinder pressure sensor / Min.: 0 V, Max.: 5 V

      When brake pedal is released:

      0.3 to 0.7 V

      		 Reading increases when brake pedal is depressed
      FL W/C Sensor FL wheel cylinder pressure sensor / Min.: 0 V, Max.: 5 V

      When brake pedal is released:

      0.3 to 0.7 V

      		 Reading increases when brake pedal is depressed
      RR W/C Sensor RR wheel cylinder pressure sensor / Min.: 0 V, Max.: 5 V

      When brake pedal is released:

      0.3 to 0.7 V

      		 Reading increases when brake pedal is depressed
      RL W/C Sensor RL wheel cylinder pressure sensor / Min.: 0 V, Max.: 5 V

      When brake pedal is released:

      0.3 to 0.7 V

      		 Reading increases when brake pedal is depressed

    5. 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

      Hydraulic Pressure

      MPa (kgf/cm2, psi)

      FR W/C Sensor

      (Data List Display)

      FL W/C Sensor

      (Data List Display)
      2.4 (24.5, 348) 0.80 to 1.20 V 0.80 to 1.20 V
      5.4 (54.1, 783) 1.40 to 1.80 V 1.40 to 1.80 V
      6.5 (66.3, 943) 1.60 to 2.00 V 1.60 to 2.00 V
      7.1 (72.4, 1030) 1.75 to 2.15 V 1.75 to 2.15 V
      for Rear Wheel Cylinder Pressure Sensor

      Hydraulic Pressure

      MPa (kgf/cm2, psi)

      RR W/C Sensor

      (Data List Display)

      RL W/C Sensor

      (Data List Display)
      2.4 (24.5, 348) 0.80 to 1.20 V 0.80 to 1.20 V
      5.0 (51.0, 725) 1.30 to 1.70 V 1.30 to 1.70 V

    NG

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    OK

  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 B

    B

    REPLACE SKID CONTROL ECU Click here

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here