LEMON Manuals: Even more car manuals for everyone
Home >> Lexus >> 2021 >> GX 460 Luxury >> Repair and Diagnosis >> Accessories & Equipment >> Exterior Lights >> Lighting System (Exterior) (Diagnostic Codes & Circuit Tests) >> Lighting System >> DTC U0242: Lost Communication With Headlamp Control Module "B" [08/2019 - 08/2021] >> Procedure

DTC U0242: Lost Communication With Headlamp Control Module "B" [08/2019 - 08/2021]: Procedure

  1. CLEAR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / AFS / Clear DTCs.
    5. Clear the DTCs.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  2

  2. CHECK FOR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Wait 10 seconds or more.
    4. Turn the Techstream on.
    5. Enter the following menus: Body Electrical / AFS / Trouble Codes.
    6. Check for DTCs.

      OK

      DTC U0242 is not output.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2019 - 08/2020]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2020 - 08/2021] 

    Result: 

    NG 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH - BATTERY AND BODY GROUND) 
    1. Disconnect the No. 1 headlight ECU sub-assembly RH connector.
      GTY961621Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to No. 1 Headlight ECU Sub-assembly RH)
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A64-4 (IG) - Body ground Engine switch on (IG) 11 to 14 V
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A64-12 (GND) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. CHECK FOR CAN BUS WIRE (NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH CAN MAIN WIRE) 
    1. Disconnect the cable from the negative (-) battery terminal.
      GTY961622Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to No. 1 Headlight ECU Sub-assembly LH)
    2. 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
      A63-22 (LCH) - A63-21 (LCL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      A63-22 (LCH) - +B Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      A63-21 (LCL) - +B Cable disconnected from negative (-) battery terminal 200 Ω or higher
      A63-22 (LCH) - GND Cable disconnected from negative (-) battery terminal 200 Ω or higher
      A63-21 (LCL) - GND Cable disconnected from negative (-) battery terminal 200 Ω or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH. Refer to  REMOVAL [08/2019 - ] 

    Result: 

    NG 

    See step  5

  5. CHECK FOR CAN BUS WIRE (NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH CAN MAIN WIRE) 
    1. Disconnect the cable from the negative (-) battery terminal.
      GTY961567Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to No. 1 Headlight ECU Sub-assembly RH)
    2. Disconnect the No. 1 headlight ECU sub-assembly RH connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A64-22 (LCH) - A64-21 (LCL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      A64-22 (LCH) - +B Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      A64-21 (LCL) - +B Cable disconnected from negative (-) battery terminal 200 Ω or higher
      A64-22 (LCH) - GND Cable disconnected from negative (-) battery terminal 200 Ω or higher
      A64-21 (LCL) - GND Cable disconnected from negative (-) battery terminal 200 Ω or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH. Refer to  REMOVAL [08/2019 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR 

scientia non olet · About LEMON Manuals