LKA/LDA SYSTEM, Diagnostic DTC:C1A74

DTC Code DTC Name
C1A74 Steering Vibrator System Malfunction

DESCRIPTION

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

DTC No. DTC Detection Condition Trouble Area
C1A74

When all of the following conditions are met:


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

  • The LKA/LDA 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 with sensor cable sub-assembly

  • Harness or connector

WIRING DIAGRAM

A000NPYE10

CAUTION / NOTICE / HINT

Note


  • Inspect the fuses for circuits related to this system before performing the following inspection 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 Recognition Camera/Target Position Memory and Recognition Camera Axis Adjust Click here.

PROCEDURE


  1. INSPECT STEERING VIBRATION ECU (IG VOLTAGE)


    1. Disconnect the z24 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
      z24-4 (BHT) - Body ground Power switch on (IG) 11 to 14 V

    NG

    CHECK HARNESS AND CONNECTOR (STEERING VIBRATOR ECU POWER SOURCE CIRCUIT) Click here

    OK

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


    1. Disconnect the z24 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
      z24-1 (EHT) - Body ground Always Below 1 Ω

    NG

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

    OK

  3. REPLACE STEERING WHEEL ASSEMBLY (STEERING VIBRATOR ECU)


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


    NEXT

  4. CHECK DTC OUTPUT (LKA/LDA SYSTEM)


    1. Clear the DTCs Click here.

    2. Make sure that the DTC detection conditions are met.

      Tech Tips

      If the detection conditions are not met, the system cannot detect the malfunction.


      1. Turn the power switch on (IG).

      2. Turn the LKA/LDA system ON.

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

    3. Check for DTCs Click here.

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

    A

    REPLACE FORWARD RECOGNITION CAMERA Click here

    B

    END (STEERING VIBRATOR ECU WAS DEFECTIVE)

  5. CHECK HARNESS AND CONNECTOR (STEERING VIBRATOR ECU POWER SOURCE CIRCUIT)


    1. Disconnect the N174 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
      N174-4 (BHT) - Body ground Power switch on (IG) 11 to 14 V

    OK

    REPLACE SPIRAL CABLE SUB-ASSEMBLY Click here

    NG

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

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


    1. Disconnect the N174 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
      N174-2 (EHT) - Body ground Always Below 1 Ω

    OK

    REPLACE SPIRAL CABLE SUB-ASSEMBLY Click here

    NG

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