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LANE DEPARTURE ALERT SYSTEM(w/ Steering Control), Diagnostic DTC:C1A74

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DTC Code DTC Name
C1A74 Steering Vibrator System Malfunction
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DESCRIPTION

If the forward recognition camera receives a steering vibration ECU malfunction signal, DTC C1A74 is stored.

DTC No. Detection Item DTC Detection Condition Trouble Area
C1A74 Steering Vibrator System Malfunction

When all of the following conditions are met:


  • The vehicle speed is 5 km/h (4 mph) or more.

  • The lane departure alert system is on.

  • A malfunction signal from the steering vibration ECU (steering wheel assembly) is detected by the forward recognition camera for 5 seconds or more.

  • Forward recognition camera

  • Steering vibration ECU (Steering wheel assembly)

  • Spiral cable sub-assembly

  • Wire harness or connector
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WIRING DIAGRAM

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CAUTION / NOTICE / HINT

Note:

  • Inspect the fuses for circuits related to this system before performing the following procedure.

  • When replacing the forward recognition camera, always replace it with a new one. If a forward recognition camera which was installed to another vehicle is used, the information stored in the forward recognition camera will not match the information from the vehicle. As a result, a DTC may be stored.

  • If the forward recognition camera has been replaced with a new one, be sure to perform forward recognition camera adjustment.

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PROCEDURE


  1. Click here

    INSPECT STEERING VIBRATION ECU (IG VOLTAGE)


    1. Disconnect the z16 spiral cable sub-assembly 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 Condition Specified Condition
      z16-4 (BHT) (spiral cable sub-assembly side) - Body ground Power switch on (IG) 11 to 14 V

    4. Turn the power switch off.

    5. Connect the z16 spiral cable sub-assembly connector.

      Result
      Proceed to
      OK
      NG

  2. Click here

    CHECK HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSEMBLY - BODY GROUND)


    1. Disconnect the z16 spiral cable sub-assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      z16-1 (EHT) (spiral cable sub-assembly side) - Body ground Always Below 1 Ω

    3. Connect the z16 spiral cable sub-assembly connector.

      Result
      Proceed to
      OK
      NG

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    REPLACE STEERING VIBRATION ECU (STEERING WHEEL ASSEMBLY)


    1. Replace the steering vibration ECU (steering wheel assembly).

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      Result
      Proceed to
      NEXT

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    CHECK FOR DTCs (LANE DEPARTURE ALERT SYSTEM)


    1. Clear the DTCs.

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      1. Chassis > LKA/LDA > Clear DTCs


    2. Perform the following procedure.

      Tip:

      If the following procedure is not performed, the previously output DTC cannot be detected.


      1. Turn the power switch on (IG).

      2. Turn the lane departure alert system ON.

      3. Drive the vehicle at a speed of 5 km/h (4 mph) or more for 5 seconds or more.

    3. Check for DTCs.

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      1. Chassis > LKA/LDA > Trouble Codes


      Result
      Result Proceed to
      DTC C1A74 is not output A
      DTC C1A74 is output B

    • A

      END (STEERING VIBRATION ECU WAS DEFECTIVE)

    • B

      REPLACE FORWARD RECOGNITION CAMERAClick here

  5. Click here

    CHECK HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSEMBLY - BODY GROUND)


    1. Disconnect the K144 spiral cable sub-assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K144-2 (EHT) (connector side) - Body ground Always Below 1 Ω

    3. Connect the K144 spiral cable sub-assembly connector.

      Result
      Proceed to
      OK
      NG

    • OK

      REPLACE SPIRAL CABLE SUB-ASSEMBLYClick here

    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR (SPIRAL CABLE SUB-ASSEMBLY - BODY GROUND)

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    CHECK HARNESS AND CONNECTOR (STEERING VIBRATION ECU POWER SOURCE CIRCUIT)


    1. Disconnect the K144 spiral cable sub-assembly 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 Condition Specified Condition
      K144-4 (BHT) (connector side) - Body ground Power switch on (IG) 11 to 14 V

    4. Turn the power switch off.

    5. Connect the K144 spiral cable sub-assembly connector.

      Result
      Proceed to
      OK
      NG

    • OK

      REPLACE SPIRAL CABLE SUB-ASSEMBLYClick here

    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR (STEERING VIBRATION ECU POWER SOURCE CIRCUIT)