CAN COMMUNICATION SYSTEM Headlight ECU LH Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
Headlight ECU LH Communication Stop Mode

Any of the following conditions are met:


  • Communication stop for "HL AutoLeveling/AFS/AHS" is indicated on the "Communication Bus Check" screen of the GTS.

    Click here

  • Communication stop history for "HL AutoLeveling/AFS/AHS" is indicated on the "Communication Bus Check (Detail)" screen of the GTS. (The Lost Communication Time value for "HL AutoLeveling/AFS/AHS" is 6 or more.)

    Click here

  • Communication system DTCs (DTCs that start with U) that correspond to "Headlight ECU LH Communication Stop Mode" in "DTC Combination Table" are output.

    Click here


  • No. 1 headlight ECU sub-assembly LH branch wire or connector

  • Power source circuit of No. 1 headlight ECU sub-assembly LH

  • No. 1 headlight ECU sub-assembly LH ground circuit

  • No. 1 headlight ECU sub-assembly LH

WIRING DIAGRAM

B004CBQE13

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

Note


  • 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.

    Click here

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

  • Before measuring the resistance of the CAN bus, turn the power 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 (-) auxiliary battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

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

    Click here

  • Some parts must be initialized and set when replacing or removing and installing parts.

    Click here

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

    DTC check procedure: Turn the power switch on (IG) and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.

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

    Click here

Tech Tips


  • Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.

  • When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

PROCEDURE


  1. CHECK FOR OPEN IN CAN BUS WIRE (NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH BRANCH WIRE)


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

    2. B004BG5C27
      *a

      Front view of wire harness connector

      (to No. 1 Headlight ECU Sub-assembly LH)

      Disconnect the No. 1 headlight ECU sub-assembly LH connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A36-24 (CANH) - A36-23 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω
      Result
      Result
      OK
      NG

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. B004BG5C28
      *a

      Front view of wire harness connector

      (to No. 1 Headlight ECU Sub-assembly LH)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A36-12 (GND) - Body ground Cable disconnected from negative (-) auxiliary battery terminal Below 1 Ω

    2. Reconnect the cable to the negative (-) auxiliary battery terminal.

      Note

      When disconnecting the cable, some systems need to be initialized after the cable is reconnected.

      Click here

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A36-4 (IG)- Body ground Power switch on (IG) 11 to 14 V
      Power switch off Below 1 V
      Result
      Result
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. B004BG5C29
      *a

      Front view of wire harness connector

      (to No. 1 Headlight ECU Sub-assembly LH)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A36-13 (ECUB) - Body ground For approximately 15 seconds after the power switch is turned on (IG) or off 11 to 14 V
      Approximately 15 seconds elapsed after turning the power switch off Below 1 V
      Result
      Result
      OK
      NG

    OK

    REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH Click here

    NG

    GO TO LIGHTING SYSTEM Click here