DSD Information System
Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Accessories & Equipment >> Exterior Lights >> Lighting System (W/ AFS) - Diagnostic Codes (1 Of 2) >> LIGHTING SYSTEM (w/ AFS) >> DTC B242F-14: ECUB Circuit Short to Ground or Open [11/2023 - ] >> Procedure

DTC B242F-14: ECUB Circuit Short to Ground or Open [11/2023 - ]: Procedure

  1. CLEAR DTC 
    1. Clear the DTCs.

      Body Electrical > Headlight Control > Clear DTCs 

      Body Electrical > Headlight Control (Sub) > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  2

  2. CHECK FOR DTC 
    1. Turn the ignition switch to ON.
    2. Wait 10 seconds or more.
    3. Check for DTCs.

      Body Electrical > Headlight Control > Trouble Codes 

      Body Electrical > Headlight Control (Sub) > Trouble Codes 

      OK

      DTC B242F-14 is not output.

      Result

      Result Proceed to
      OK A
      NG (DTC output from headlight ECU sub-assembly LH) B
      NG (DTC output from headlight ECU sub-assembly RH) C

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ] 

    Result: 

    C 

    See step  10

    Result: 

    B 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY LH - AUXILIARY BATTERY) 
    GTY1178843Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Headlight ECU Sub-assembly LH)
    1. Disconnect the headlight ECU sub-assembly LH connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A87-13 (ECUB) - Body ground Ignition switch ON 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  5

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY LH - BODY GROUND) 
    1. Disconnect the headlight ECU sub-assembly LH connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A87-12 (GND) - Body ground Always Below 1 Ω
      GTY1178844Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Headlight ECU Sub-assembly LH)

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE HEADLIGHT ECU SUB-ASSEMBLY LH. Refer to  REMOVAL [11/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  5. INSPECT H-LP LH RELAY 

    Refer to ON-VEHICLE INSPECTION [12/2019 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE H-LP LH RELAY 

    Result: 

    OK 

    See step  6

  6. CHECK HARNESS AND CONNECTOR (H-LP LH RELAY - HEADLIGHT ECU SUB-ASSEMBLY LH) 
    1. Remove the H-LP LH relay.
    2. Disconnect the A87 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
      3 (H-LP LH relay) - A87-13 (ECUB) Always Below 1 Ω
      3 (H-LP LH relay) or A87-13 (ECUB) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (H-LP LH RELAY - AUXILIARY BATTERY) 
    1. Remove the H-LP LH relay.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      2 (H-LP LH relay) - Body ground Ignition switch off 11 to 14 V
      5 (H-LP LH relay) - Body ground Ignition switch off 11 to 14 V
      GTY510431Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to H-LP LH Relay)

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (H-LP LH RELAY - POWER DISTRIBUTION BOX ASSEMBLY) 
    1. Remove the H-LP LH relay.
    2. Disconnect the 8E power distribution box assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      1 (H-LP LH relay) - 8E-6 Always Below 1 Ω
      1 (H-LP LH relay) or 8E-6 - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  9

  9. INSPECT POWER DISTRIBUTION BOX ASSEMBLY 
    GTY1180252Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Component without harness connected
    (Power Distribution Box Assembly)    		 - -
    1. Remove the power distribution box assembly.

      Refer to REMOVAL [11/2023 - ]

    2. Remove the main body ECU (multiplex network body ECU) from the power distribution box assembly.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      8E-6 - MB-8 (HRLY) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [11/2023 - ] 

    Result: 

    NG 

    REPLACE POWER DISTRIBUTION BOX ASSEMBLY. Refer to  REMOVAL [11/2023 - ] 

  10. CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY RH - AUXILIARY BATTERY) 
    GTY1179342Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Headlight ECU Sub-assembly RH)
    1. Disconnect the headlight ECU sub-assembly RH connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A16-13 (ECUB) - Body ground Ignition switch ON 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  12

    Result: 

    OK 

    See step  11

  11. CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY RH - BODY GROUND) 
    1. Disconnect the headlight ECU sub-assembly RH connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A16-12 (GND) - Body ground Always Below 1 Ω
      GTY1178847Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Headlight ECU Sub-assembly RH)

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE HEADLIGHT ECU SUB-ASSEMBLY RH. Refer to  REMOVAL [11/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  12. INSPECT H-LP RH RELAY 

    Refer to ON-VEHICLE INSPECTION [12/2019 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE H-LP RH RELAY 

    Result: 

    OK 

    See step  13

  13. CHECK HARNESS AND CONNECTOR (H-LP RH RELAY - HEADLIGHT ECU SUB-ASSEMBLY RH) 
    1. Remove the H-LP RH relay.
    2. Disconnect the A16 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
      3 (H-LP RH relay) - A16-13 (ECUB) Always Below 1 Ω
      3 (H-LP RH relay) or A16-13 (ECUB) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  14

  14. CHECK HARNESS AND CONNECTOR (H-LP RH RELAY - AUXILIARY BATTERY) 
    1. Remove the H-LP RH relay.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      2 (H-LP RH relay) - Body ground Ignition switch off 11 to 14 V
      5 (H-LP RH relay) - Body ground Ignition switch off 11 to 14 V
      GTY510431Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to H-LP RH Relay)

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  15

  15. CHECK HARNESS AND CONNECTOR (H-LP RH RELAY - POWER DISTRIBUTION BOX ASSEMBLY) 
    1. Remove the H-LP RH relay.
    2. Disconnect the 8E power distribution box assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      1 (H-LP RH relay) - 8E-10 Always Below 1 Ω
      1 (H-LP RH relay) or 8E-10 - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  16

  16. INSPECT POWER DISTRIBUTION BOX ASSEMBLY 
    GTY1179170Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Component without harness connected
    (Power Distribution Box Assembly)    		 - -
    1. Remove the power distribution box assembly.

      Refer to REMOVAL [11/2023 - ]

    2. Remove the main body ECU (multiplex network body ECU) from the power distribution box assembly.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      8E-10 - MB-9 (HRY2) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [11/2023 - ] 

    Result: 

    NG 

    REPLACE POWER DISTRIBUTION BOX ASSEMBLY. Refer to  REMOVAL [11/2023 - ] 

Diesel-Data.com