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PRE-COLLISION SYSTEM, Diagnostic DTC:U023A, U1002

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DTC Code DTC Name
U023A Lost Communication with Front Camera Module
U1002 Lost Communication with Gateway Module
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DESCRIPTION

DTC No. Detection Item DTC Detection Condition Trouble Area
U023A Lost Communication with Front Camera Module After the ignition switch is turned to ON, a communication malfunction occurs between the millimeter wave radar sensor assembly and forward recognition camera.

  • CAN bus sab line or connector

  • Forward recognition camera system

  • Forward recognition camera

  • Millimeter wave radar sensor assembly
U1002 Lost Communication with Gateway Module When the ignition switch to ON, a communication error between the forward recognition camera and millimeter wave radar sensor assembly is detected for approximately 1 second.

  • CAN bus sab line or connector

  • Forward recognition camera system

  • Forward recognition camera

  • Millimeter wave radar sensor assembly
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WIRING DIAGRAM

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CAUTION / NOTICE / HINT

Note:

  • w/o Stop and Start System:

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

  • Before measuring the resistance of the CAN bus, turn the ignition switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

  • After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.

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  • If the forward recognition camera has been replaced with a new one, be sure to perform Forward Recognition Axis Adjustment.

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  • When the millimeter wave radar sensor assembly is replaced with a new one, adjustment of the radar sensor beam axis must be performed.

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Tip:

  • Operating the ignition switch, any other switches or a door triggers related ECUs and sensors to communicate using the CAN communication system. This communication will cause the resistance value to change.

  • Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the connectors of ECUs or wire harnesses while performing the inspection below may help determine the cause of the malfunction.

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PROCEDURE


  1. Click here

    CHECK FOR DTCs (PRE-COLLISION SYSTEM)


    1. Check for DTCs.

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      1. Body Electrical > Pre-Collision 2 > Trouble Codes


      Result
      Result Proceed to
      DTC U023A and/or U1002 and other DTCs are output A
      Only DTC U023A and/or U1002 is output B

  2. Click here

    CHECK FOR OPEN IN CAN BUS SAB LINES (FORWARD RECOGNITION CAMERA)


    1. Disconnect the cable from the negative (-) battery terminal.

    2. B00264TC04
      *a

      Front view of wire harness connector

      (to Forward Recognition Camera)

      Disconnect the Q4 forward recognition camera connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Q4-6 (CANH) - Q4-12 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

    4. Connect the Q4 forward recognition camera connector.

      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE CAN BUS SAB LINE OR CONNECTOR (FORWARD RECOGNITION CAMERA - MILLIMETER WAVE RADAR SENSOR ASSEMBLY)

  3. Click here

    CHECK HARNESS AND CONNECTOR (POWER SOURCE VOLTAGE (FORWARD RECOGNITION CAMERA))


    1. B00264TC06
      *a

      Front view of wire harness connector

      (to Forward Recognition Camera)

      Disconnect the Q4 forward recognition camera connector.

    2. Connect the cable to the negative (-) battery terminal.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      Q4-7 (IGB) - Body ground Ignition switch ON

      11 to 14 V*1

      10.5 to 16 V*2
      *1: w/o Stop and Start System *2: w/ Stop and Start System

    4. Connect the Q4 forward recognition camera connector.

      Result
      Proceed to
      OK
      NG (w/o Stop and Start System)
      NG (w/ Stop and Start System)

    • OKClick here
    • NG (w/o Stop and Start System)

      REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    • NG (w/ Stop and Start System)

      INSPECT STOP AND START SYSTEM (BACKUP BOOST CONVERTER CIRCUIT)Click here

  4. Click here

    CHECK HARNESS AND CONNECTOR (FORWARD RECOGNITION CAMERA - BODY GROUND)


    1. B00264TC07
      *a

      Front view of wire harness connector

      (to Forward Recognition Camera)

      Disconnect the Q4 forward recognition camera connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Q4-10 (GND) - Body ground Always Below 1 Ω

    3. Connect the Q4 forward recognition camera connector.

      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  5. Click here

    CHECK HARNESS AND CONNECTOR (POWER SOURCE VOLTAGE (MILLIMETER WAVE RADAR SENSOR ASSEMBLY))


    1. B0024I2C69
      *a

      Front view of wire harness connector

      (to Millimeter Wave Radar Sensor Assembly)

      Disconnect the A64 millimeter wave radar sensor assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A64-8 (IGB) - Body ground Ignition switch ON

      11 to 14 V*1

      10.5 to 16 V*2
      *1: w/o Stop and Start System *2: w/ Stop and Start System

    3. Connect the A64 millimeter wave radar sensor assembly connector.

      Result
      Proceed to
      OK
      NG (w/o Stop and Start System)
      NG (w/ Stop and Start System)

    • OKClick here
    • NG (w/o Stop and Start System)

      REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    • NG (w/ Stop and Start System)

      INSPECT STOP AND START SYSTEM (BACKUP BOOST CONVERTER CIRCUIT)Click here

  6. Click here

    CHECK HARNESS AND CONNECTOR (MILLIMETER WAVE RADAR SENSOR ASSEMBLY - BODY GROUND)


    1. B0024I2C70
      *a

      Front view of wire harness connector

      (to Millimeter Wave Radar Sensor Assembly)

      Disconnect the A64 millimeter wave radar sensor assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A64-1 (SGND) - Body ground Always Below 1 Ω

    3. Connect the A64 millimeter wave radar sensor assembly connector.

      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  7. Click here

    REPLACE FORWARD RECOGNITION CAMERA


    1. Replace the forward recognition camera.

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    2. Perform Forward Recognition Axis Adjustment.

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      Result
      Proceed to
      NEXT

  8. Click here

    CHECK FOR DTCs (PRE-COLLISION SYSTEM)


    1. Clear the DTCs.

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      1. Body Electrical > Pre-Collision 2 > Clear DTCs


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

      Tip:

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

    3. Check for DTCs.

      Click here


      1. Body Electrical > Pre-Collision 2 > Trouble Codes


      Result
      Result Proceed to
      DTC U023A is not output A
      DTC U023A is output B

    • A

      END (FORWARD RECOGNITION CAMERA WAS DEFECTIVE)

    • BClick here
  9. Click here

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY


    1. Replace the millimeter wave radar sensor assembly.

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    2. Adjust the millimeter wave radar sensor assembly.

      Click here

      Result
      Proceed to
      NEXT

  10. Click here

    CLEAR DTC (PRE-COLLISION SYSTEM)


    1. Clear the DTCs.

      Click here


      1. Body Electrical > Pre-Collision 2 > Clear DTCs


      Result
      Proceed to
      NEXT

    • NEXT

      END (MILLIMETER WAVE RADAR SENSOR ASSEMBLY WAS DEFECTIVE)