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ANTI-LOCK BRAKE SYSTEM, Diagnostic DTC:C1405, C1406

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DTC Code DTC Name
C1405 Open or Short in Front Speed Sensor RH Circuit
C1406 Open or Short in Front Speed Sensor LH Circuit
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DESCRIPTION

Refer to DTCs C1271, C1272, C1401 and C1402.

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DTC No. Detection Item DTC Detection Condition Trouble Area Note
C1405 Open or Short in Front Speed Sensor RH Circuit

Either of the following is detected:


  1. An open in the speed sensor signal circuit continues for 0.5 seconds or more.

  2. With the +BS terminal voltage at 9.5 V or higher, the sensor power supply voltage decreases for 0.5 seconds or more.

  • Front speed sensor RH

  • Skid control ECU (Brake actuator assembly)

  • Wire harness or connector

 -
C1406 Open or Short in Front Speed Sensor LH Circuit

Either of the following is detected:


  1. An open in the speed sensor signal circuit continues for 0.5 seconds or more.

  2. With the +BS terminal voltage at 9.5 V or higher, the sensor power supply voltage decreases for 0.5 seconds or more.

  • Front speed sensor LH

  • Skid control ECU (Brake actuator assembly)

  • Wire harness or connector

 -
Table 1. *a Front Speed Sensor RH *b Front Speed Sensor LH *c Skid Control ECU (Brake Actuator Assembly)
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WIRING DIAGRAM

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CAUTION / NOTICE / HINT

Note:

When replacing the skid control ECU (brake actuator assembly), perform Test Mode (Signal Check) to acquire the rear differential lock identification information.

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PROCEDURE


  1. Click here

    CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION)


    1. Using the GTS, check for any momentary interruption in the wire harness and connector corresponding to the DTC.

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      1. Chassis > ABS/VSC/TRC > Data List
        Tester Display Measurement Item Range Normal Condition Diagnostic Note
        FR Speed Open Front speed sensor RH open detection Normal or Error Normal Error: Momentary interruption
        FL Speed Open Front speed sensor LH open detection Normal or Error Normal Error: Momentary interruption




      1. Chassis > ABS/VSC/TRC > Data List
        Tester Display
        FR Speed Open
        FL Speed Open





      OK
      Normal (There are no momentary interruptions.)
      Tip:

      Perform the above inspection before removing the sensor and connector.

      Result
      Proceed to
      OK
      NG

  2. Click here

    READ VALUE USING GTS (FRONT SPEED SENSOR)


    1. Connect the GTS to the DLC3.

    2. Start the engine.

    3. Turn the GTS on.

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

    5. According to the display on the GTS, read the Data List.


      1. Chassis > ABS/VSC/TRC > Data List
        Tester Display Measurement Item Range Normal Condition Diagnostic Note
        FR Wheel Speed Front wheel speed sensor RH reading

        Min.: 0 km/h (0 mph)

        Max.: 326.4 km/h (202 mph)

        		 Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations
        FL Wheel Speed Front wheel speed sensor LH reading

        Min.: 0 km/h (0 mph)

        Max.: 326.4 km/h (202 mph)

        		 Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations




      1. Chassis > ABS/VSC/TRC > Data List
        Tester Display
        FR Wheel Speed
        FL Wheel Speed





    6. Check that there is no difference between the speed value output from the speed sensor displayed on the GTS and the speed value displayed on the speedometer when driving the vehicle.

      Tip:

      Factors that affect the indicated vehicle speed include tire size, tire inflation and tire wear. The speed indicated on the speedometer has an allowable margin of error. This can be tested using a speedometer tester (calibrated chassis dynamometer). For details about testing and the margin of error, see the reference chart.

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      OK
      The speed value output from the speed sensor displayed on the GTS is the same as the actual vehicle speed measured using a speedometer tester (calibrated chassis dynamometer).
      Tip:

      If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step.

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      Result
      Proceed to
      OK
      NG

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    RECONFIRM DTC


    1. Turn the ignition switch off.

    2. Clear the DTCs.

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      1. Chassis > ABS/VSC/TRC > Clear DTCs


    3. Turn the ignition switch off.

    4. Start the engine.

    5. Perform a road test

    6. Check if the same DTC is recorded.

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      1. Chassis > ABS/VSC/TRC > Trouble Codes


      Result
      Proceed to
      DTCs C1405 and C1406 are not output
      DTCs C1405 and/or C1406 are output

    • DTCs C1405 and C1406 are not output

      USE SIMULATION METHOD TO CHECKClick here

    • DTCs C1405 and/or C1406 are output

      REPLACE BRAKE ACTUATOR ASSEMBLYClick here

  4. Click here

    CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - FRONT SPEED SENSOR)


    1. Turn the ignition switch off.

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

    3. Disconnect the A3 skid control ECU (brake actuator assembly) connector and the A8 and/or A9 front speed sensor connector.

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

      Standard Resistance
      Table 2. for RH
      Tester Connection Condition Specified Condition
      A3-7 (FR+) - A8-2 (FR+) Always Below 1 Ω
      A3-6 (FR-) - A8-1 (FR-) Always Below 1 Ω
      A3-7 (FR+) or A8-2 (FR+) - Body ground Always 10 kΩ or higher
      A3-6 (FR-) or A8-1 (FR-) - Body ground Always 10 kΩ or higher
      Table 3. for LH
      Tester Connection Condition Specified Condition
      A3-19 (FL+) - A9-2 (FL+) Always Below 1 Ω
      A3-18 (FL-) - A9-1 (FL-) Always Below 1 Ω
      A3-19 (FL+) or A9-2 (FL+) - Body ground Always 10 kΩ or higher
      A3-18 (FL-) or A9-1 (FL-) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

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    INSPECT BRAKE ACTUATOR ASSEMBLY (SENSOR OUTPUT)


    1. B0027AAC12
      *A for RH
      *B for LH
      *a

      Front view of wire harness connector

      (to Front Speed Sensor)

      Reconnect the A3 skid control ECU (brake actuator assembly) connector.

    2. Turn the ignition switch to ON.

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

      Standard Voltage
      Table 4. for RH
      Tester Connection Switch Condition Specified Condition
      A8-2 (FR+) - Body ground Ignition switch ON 8 to 14 V
      Table 5. for LH
      Tester Connection Switch Condition Specified Condition
      A9-2 (FL+) - Body ground Ignition switch ON 8 to 14 V
      Result
      Proceed to
      OK
      NG

    • OK

      REPLACE FRONT SPEED SENSOR for 2WD other than Pre-Runner:Click here

      REPLACE FRONT SPEED SENSOR for 4WD and Pre-Runner:Click here

    • NG

      REPLACE BRAKE ACTUATOR ASSEMBLYClick here