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Home >> Toyota >> 2017 >> Mirai >> Repair and Diagnosis (Single Page) >> Brakes >> Mechanical - Hydraulic >> Electronically Controlled Brake System - Diagnostic Codes (2 Of 2) & Circuit Tests >> Electronically Controlled Brake System >> DTC C1271-71: Low Output Signal of Front Speed Sensor RH (Test Mode DTC); DTC C1272-72: Low Output Signal of Front Speed Sensor LH (Test Mode DTC); DTC C1464-31: Front Speed Sensor RH Circuit; DTC C1465-32: Front Speed Sensor LH Circuit [06/2015 - ] >> Procedure
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DTC C1271-71: Low Output Signal of Front Speed Sensor RH (Test Mode DTC); DTC C1272-72: Low Output Signal of Front Speed Sensor LH (Test Mode DTC); DTC C1464-31: Front Speed Sensor RH Circuit; DTC C1465-32: Front Speed Sensor LH Circuit [06/2015 - ]: Procedure

  1. CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION) 
    1. Using the Techstream, check for any momentary interruptions in the wire harness and connector corresponding to a DTC.

      Refer to CHECK FOR INTERMITTENT PROBLEMS [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      FR Speed Open Front speed sensor RH open detection Error or Normal Normal: Normal Error: Momentary interruption
      FL Speed Open Front speed sensor LH open detection Error or Normal Normal: Normal Error: Momentary interruption

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display
      FR Speed Open
      FL Speed Open

      OK

      Normal (There are no momentary interruptions.)

      HINT: 

      Perform the above inspection before removing the sensor and connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  5

    Result: 

    OK 

    See step  2

  2. READ VALUE USING TECHSTREAM (FRONT SPEED SENSOR) 
    1. Select the Data List on the Techstream.

      Refer to DATA LIST / ACTIVE TEST [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      FR Wheel Speed Front speed sensor RH Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph) Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations
      FL Wheel Speed Front speed sensor LH Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph) Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display
      FR Wheel Speed
      FL Wheel Speed
    2. Check the speed value output from the speed sensor displayed on the Techstream.

      HINT: 

      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.

      Refer to OPERATION CHECK [06/2015 - 11/2018] , or refer to OPERATION CHECK [11/2018 - ]

      OK

      The speed value output from the speed sensor displayed on the Techstream is similar to the speed indicated on the speedometer.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  5

    Result: 

    OK 

    See step  3

  3. PERFORM TEST MODE INSPECTION (SIGNAL CHECK) 
    1. Turn the power switch off.
    2. Perform the sensor check in Test Mode Procedure.

      Refer to TEST MODE PROCEDURE [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Utility 

      Tester Display
      Signal Check

      OK

      All Test Mode DTCs are cleared.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  5

    Result: 

    OK 

    See step  4

  4. RECONFIRM DTC 
    1. Turn the power switch off.
    2. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Clear DTCs 

    3. Turn the power switch on (READY).
    4. Perform a road test.
    5. Check if the same DTC is output.

      Refer to DTC CHECK / CLEAR [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      Result

      Result Proceed to
      DTCs C1464/31 and C1465/32 are not output. A
      DTCs C1464/31 and/or C1465/32 are output. B

      HINT: 

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

      Refer to PROBLEM SYMPTOMS TABLE [06/2015 - ]

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [06/2015 - 11/2018]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2018 - ] 

    Result: 

    B 

    See step  10

  5. CHECK FRONT SPEED SENSOR INSTALLATION 
    1. Turn the power switch off.
      GTY495780Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a No clearance
      *b OK
      *c NG
    2. Check the speed sensor installation.

      Refer to INSTALLATION [06/2015 - ]

      OK

      There is no clearance between the sensor and the front steering knuckle.

      The installation bolt is tightened properly.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    INSTALL FRONT SPEED SENSOR CORRECTLY. Refer to  INSTALLATION [06/2015 - ] 

    Result: 

    OK 

    See step  6

  6. CHECK FRONT SPEED SENSOR TIP 
    1. Remove the front speed sensor.

      Refer to REMOVAL [06/2015 - ]

    2. Check the front speed sensor tip.

      OK

      The sensor tip is free of scratches, oil, and foreign matter.

      NOTE:
      • If no damage to the speed sensor tip is found during this inspection, do not replace the speed sensor.
      • Check the speed sensor signal after cleaning or replacement.

        Refer to TEST MODE PROCEDURE [06/2015 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CLEAN OR REPLACE FRONT SPEED SENSOR 

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - FRONT SPEED SENSOR) 
    1. Install the front speed sensor.

      Refer to INSTALLATION [06/2015 - ]

    2. Make sure that there is no looseness at the locking part and the connecting part of the connectors.
    3. Disconnect the A63 skid control ECU (brake booster with master cylinder assembly) connector.
    4. Disconnect the A33 or A12 front speed sensor connector.
    5. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      FOR RH

      Tester Connection Condition Specified Condition
      A63-18 (FR+) - A33-2 (FR+) Always Below 1 Ω
      A63-18 (FR+) or A33-2 (FR+) - Body ground Always 10 kΩ or higher
      A63-5 (FR-) - A33-1 (FR-) Always Below 1 Ω
      A63-5 (FR-) or A33-1 (FR-) - Body ground Always 10 kΩ or higher
      FOR LH

      Tester Connection Condition Specified Condition
      A63-31 (FL+) - A12-2 (FL+) Always Below 1 Ω
      A63-31 (FL+) or A12-2 (FL+) - Body ground Always 10 kΩ or higher
      A63-32 (FL-) - A12-1 (FL-) Always Below 1 Ω
      A63-32 (FL-) or A12-1 (FL-) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. INSPECT BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (SENSOR OUTPUT) 
    1. Reconnect the A63 skid control ECU (brake booster with master cylinder assembly) connector.
      GTY564713Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Front Speed Sensor)
      *b For RH
      *c For LH
    2. Turn the power switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      FOR RH

      Tester Connection Switch Condition Specified Condition
      A33-2 (FR+) - Body ground Power switch on (IG) 5.7 to 14 V
      FOR LH

      Tester Connection Switch Condition Specified Condition
      A12-2 (FL+) - Body ground Power switch on (IG) 5.7 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to  REMOVAL [06/2015 - 11/2018]  , or refer to  REMOVAL [11/2018 - ] 

    Result: 

    OK 

    See step  9

  9. RECONFIRM DTC 
    1. Turn the power switch off.
    2. Reconnect the A33 or A12 front speed sensor connector.
    3. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Clear DTCs 

    4. Turn the power switch on (READY).
    5. Perform a road test.
    6. Check if the same DTC is output.

      Refer to DTC CHECK / CLEAR [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      Result

      Result Proceed to
      DTCs C1464/31 and/or C1465/32 are output. A
      DTCs C1464/31 and C1465/32 are not output. B

      HINT: 

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

      Refer to PROBLEM SYMPTOMS TABLE [06/2015 - ]

    Result: 

    B 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [06/2015 - 11/2018]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2018 - ] 

    Result: 

    A 

    See step  10

  10. REPLACE FRONT SPEED SENSOR 
    1. Turn the power switch off.
    2. Replace the front speed sensor.

      Refer to REMOVAL [06/2015 - ]

      NOTE:

      Check the speed sensor signal after replacement.

      Refer to TEST MODE PROCEDURE [06/2015 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  11

  11. RECONFIRM DTC 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Clear DTCs 

    2. Turn the power switch on (READY).
    3. Perform a road test.
    4. Check if the same DTC is output.

      Refer to DTC CHECK / CLEAR [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      Result

      Result Proceed to
      DTCs C1464/31 and/or C1465/32 are output. A
      DTCs C1464/31 and C1465/32 are not output. B

      HINT: 

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

      Refer to PROBLEM SYMPTOMS TABLE [06/2015 - ]

    Result: 

    B 

    END 

    Result: 

    A 

    See step  12

  12. REPLACE FRONT AXLE HUB SUB-ASSEMBLY 
    1. Turn the power switch off.
    2. Replace the front speed sensor rotor (front axle hub sub-assembly).

      Refer to REMOVAL [06/2015 - 11/2018] , or refer to REMOVAL [11/2018 - ]

      HINT: 

      The front speed sensor rotor is incorporated into the front axle hub sub-assembly.

      If the front speed sensor rotor needs to be replaced, replace the front axle hub sub-assembly.

      NOTE:

      Check the speed sensor signal after replacement.

      Refer to TEST MODE PROCEDURE [06/2015 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  13

  13. RECONFIRM DTC 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Clear DTCs 

    2. Turn the power switch on (READY).
    3. Perform a road test.
    4. Check if the same DTC is output.

      Refer to DTC CHECK / CLEAR [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      Result

      Result Proceed to
      DTCs C1464/31 and/or C1465/32 are output. A
      DTCs C1464/31 and C1465/32 are not output. B

      HINT: 

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

      Refer to PROBLEM SYMPTOMS TABLE [06/2015 - ]

    Result: 

    A 

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to  REMOVAL [06/2015 - 11/2018]  , or refer to  REMOVAL [11/2018 - ] 

    Result: 

    B 

    END 

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