CAN COMMUNICATION SYSTEM(for LHD), Diagnostic DTC:U023A

DTC Code DTC Name
U023A Lost Communication with Front Camera Module

DESCRIPTION

DTC No. Detection Item DTC Detection Condition Trouble Area Note
U023A Lost Communication with Front Camera Module No communication from the inner rear view mirror assembly continues.

  • Inner rear view mirror assembly branch line or connector

  • Power source circuit of inner rear view mirror assembly

  • Inner rear view mirror assembly ground circuit

  • Inner rear view mirror assembly

Tech Tips

The network gateway ECU stores DTCs when it detects a communication stop or network communication error for ECUs connected to sub bus 2.

Tech Tips

The diagnostic procedure is for when DTC U023A is output by the network gateway ECU (GTS display: Gateway).

WIRING DIAGRAM

B006QYJE06

CAUTION / NOTICE / HINT

Note


  • Before measuring the resistance of the CAN bus, turn the engine 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 engine 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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  • Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.

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  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

  • DTC check procedure: Turn the engine switch on (IG) and wait at least 10 seconds.

  • After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed.

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

Tech Tips


  • Operating the engine switch, any other switches or a door triggers related ECU and sensor communication on the CAN. 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 ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.

PROCEDURE


  1. RECONFIRM DTC OUTPUT


    1. Reconfirm DTCs.


      Body Electrical > Gateway > Trouble Codes

      Tech Tips

      If DTC U1002 is output from Gateway of the network gateway ECU, this indicates a sub bus 2 malfunction. Troubleshoot for DTC U1002 and check for malfunctions in sub bus 2.

      Result
      Result Proceed to
      DTC U1002 is not output from the network gateway ECU (GTS display: Gateway) A
      DTC U1002 is output from the network gateway ECU (GTS display: Gateway) B

    B

    GO TO DIAGNOSTIC PROCEDURE INDICATED BY OUTPUT DTC Click here

    A

  2. CHECK FOR OPEN IN SUB BUS 2 LINES (INNER REAR VIEW MIRROR ASSEMBLY BRANCH LINE)


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

    2. B006KTYC06
      *a

      Front view of wire harness connector

      (to Inner Rear View Mirror Assembly)

      Disconnect the S22 inner rear view mirror assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      S22-9 (CANH) - S22-10 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      Result
      Result
      OK
      NG

    NG

    REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (INNER REAR VIEW MIRROR ASSEMBLY)

    OK

  3. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. B006KTYC09
      *a

      Front view of wire harness connector

      (to Inner Rear View Mirror Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      S22-2 (E) - Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω

    2. Reconnect 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
      S22-1 (IG) - Body ground Engine switch on (IG) 11 to 14 V
      Result
      Result
      OK
      NG

    OK

    REPLACE INNER REAR VIEW MIRROR ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)