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Home >> Toyota >> 2021 >> Mirai XLE >> Repair and Diagnosis >> Accessories & Equipment >> Exterior Lights >> Lighting System (W/O Headlight Ecu) - Diagnostic Codes & Circuit Tests >> LIGHTING SYSTEM (w/o Headlight ECU) >> Taillight Circuit [11/2020 - 12/2022] >> Procedure

Taillight Circuit [11/2020 - 12/2022]: Procedure

  1. INSPECT LIGHTS 
    1. Check the problem symptoms.

      Result

      Proceed to Proceed to
      All taillights, license plate light, front side marker light parking light and the rear side marker lights do not illuminate A
      The rear combination light assembly (taillight), front side marker light parking light and rear side marker light assembly do not illuminate B
      The rear light assembly (taillight) and license plate light do not illuminate C

    Result: 

    B 

    See step  3

    Result: 

    C 

    See step  14

    Result: 

    A 

    See step  2

  2. READ VALUE USING GTS 
    1. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Tail Input Signal Light control switch tail position input signal OFF or ON OFF: Light control switch in neither tail nor head position
      ON: Light control switch in tail or head position      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Tail Input Signal

      OK

      Display changes according to the light control switch operation.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 2 SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [11/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 12/2022] 

    Result: 

    NG 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [11/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 12/2022] 

  3. READ VALUE USING GTS 
    1. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Tail Light No. 1 Output Signal Taillight output OFF or ON OFF: Taillight not illuminated
      ON: Taillight illuminated      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Tail Light No. 1 Output Signal

      OK

      Display changes according to the light control switch operation.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE NO. 2 SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [11/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 12/2022] 

    Result: 

    OK 

    See step  4

  4. READ VALUE USING GTS 
    1. Turn the light control switch tail position.
    2. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Tail Light No. 1 Fuse Taillight fuse Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Status of Tail Light No. 1 Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [11/2020 - 12/2023] 

    Result: 

    NG 

    See step  5

  5. CHECK REAR COMBINATION LIGHT CORD RH 
    1. Disconnect the G72 rear combination light cord RH connector.
    2. Turn the light control switch tail position.
    3. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Tail Light No. 1 Fuse Taillight fuse Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Status of Tail Light No. 1 Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  6

  6. CHECK REAR TURN SIGNAL LIGHT LED 
    1. Disconnect the rear turn signal light LED connector.
    2. Turn the light control switch tail position.
    3. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Tail Light No. 1 Fuse Taillight fuse Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Status of Tail Light No. 1 Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE REAR TURN SIGNAL LIGHT LED. Refer to  DISASSEMBLY [11/2020 - ] 

    Result: 

    NG 

    REPLACE REAR COMBINATION LIGHT CORD RH. Refer to  DISASSEMBLY [11/2020 - ] 

  7. CHECK REAR COMBINATION LIGHT CORD LH 
    1. Disconnect the G73 rear combination light cord LH connector.
    2. Turn the light control switch tail position.
    3. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Tail Light No. 1 Fuse Taillight fuse Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Status of Tail Light No. 1 Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  9

    Result: 

    OK 

    See step  8

  8. CHECK REAR TURN SIGNAL LIGHT LED 
    1. Disconnect the rear turn signal light LED connector.
    2. Turn the light control switch tail position.
    3. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Tail Light No. 1 Fuse Taillight fuse Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Status of Tail Light No. 1 Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE REAR TURN SIGNAL LIGHT LED. Refer to  DISASSEMBLY [11/2020 - ] 

    Result: 

    NG 

    REPLACE REAR COMBINATION LIGHT CORD LH. Refer to  DISASSEMBLY [11/2020 - ] 

  9. CHECK REAR SIDE MARKER LIGHT ASSEMBLY RH 
    1. Disconnect the J26 rear side marker light assembly RH connector.
    2. Turn the light control switch tail position.
    3. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Tail Light No. 1 Fuse Taillight fuse Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Status of Tail Light No. 1 Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE REAR SIDE MARKER LIGHT ASSEMBLY RH. Refer to  REMOVAL [11/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    See step  10

  10. CHECK REAR SIDE MARKER LIGHT ASSEMBLY LH 
    1. Disconnect the J27 rear side marker light assembly LH connector.
    2. Turn the light control switch tail position.
    3. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Tail Light No. 1 Fuse Taillight fuse Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Status of Tail Light No. 1 Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE REAR SIDE MARKER LIGHT ASSEMBLY LH. Refer to  REMOVAL [11/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    See step  11

  11. CHECK HEADLIGHT ASSEMBLY LH 
    1. Disconnect the A29 headlight assembly LH connector.
    2. Turn the light control switch tail position.
    3. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Tail Light No. 1 Fuse Taillight fuse Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Status of Tail Light No. 1 Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE HEADLIGHT ASSEMBLY LH. Refer to  REMOVAL [11/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 12/2022] 

    Result: 

    NG 

    See step  12

  12. CHECK HEADLIGHT ASSEMBLY RH 
    1. Disconnect the A28 headlight assembly RH connector.
    2. Turn the light control switch tail position.
    3. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Tail Light No. 1 Fuse Taillight fuse Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Status of Tail Light No. 1 Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE HEADLIGHT ASSEMBLY RH. Refer to  REMOVAL [11/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 12/2022] 

    Result: 

    NG 

    See step  13

  13. CHECK HARNESS AND CONNECTOR (REAR COMBINATION LIGHT CORD RH - NO. 2 SEMICONDUCTOR POWER INTEGRATION ECU) 
    1. Disconnect the cable from the negative (-) auxiliary battery terminal.
    2. Disconnect the G72 rear combination light cord RH connector.
    3. Disconnect the G73 rear combination light cord LH connector.
    4. Disconnect the J26 rear side marker light assembly RH connector.
    5. Disconnect the J27 rear side marker light assembly LH connector.
    6. Disconnect the A29 headlight assembly LH connector.
    7. Disconnect the A28 headlight assembly RH connector.
    8. Disconnect the G102 No. 2 semiconductor power integration ECU connector.
    9. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G72-1 (B) or G102-16 (L) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 2 SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [11/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 12/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  14. READ VALUE USING GTS 
    1. Turn the light control switch tail position.
    2. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Tail Light No. 2 Output Signal Taillight output OFF or ON OFF: Taillight not illuminated
      ON: Taillight illuminated      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Tail Light No. 2 Output Signal

      OK

      Display changes according to the light control switch operation.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE NO. 2 SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [11/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 12/2022] 

    Result: 

    OK 

    See step  15

  15. READ VALUE USING GTS 
    1. Turn the light control switch tail position.
    2. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Tail Light No. 2 Fuse Taillight fuse Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Status of Tail Light No. 2 Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [11/2020 - 12/2023] 

    Result: 

    NG 

    See step  16

  16. CHECK REAR LIGHT ASSEMBLY RH 
    1. Disconnect the K10 rear light assembly RH connector.
    2. Turn the light control switch tail position.
    3. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Tail Light No. 2 Fuse Taillight fuse Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Status of Tail Light No. 2 Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  18

    Result: 

    OK 

    See step  17

  17. CHECK REAR LIGHT SOCKET AND WIRE RH 
    1. Disconnect the rear light socket and wire RH connector.
    2. Turn the light control switch tail position.
    3. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Tail Light No. 2 Fuse Taillight fuse Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Status of Tail Light No. 2 Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE REAR LIGHT SOCKET AND WIRE RH. Refer to  DISASSEMBLY [11/2020 - ] 

    Result: 

    NG 

    REPLACE REAR LIGHT ASSEMBLY RH. Refer to  REMOVAL [11/2020 - ] 

  18. CHECK REAR LIGHT ASSEMBLY LH 
    1. Disconnect the K6 rear light assembly LH connector.
    2. Turn the light control switch tail position.
    3. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Tail Light No. 2 Fuse Taillight fuse Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Status of Tail Light No. 2 Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  20

    Result: 

    OK 

    See step  19

  19. CHECK REAR LIGHT SOCKET AND WIRE LH 
    1. Disconnect the rear light socket and wire LH connector.
    2. Turn the light control switch tail position.
    3. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Tail Light No. 2 Fuse Taillight fuse Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Status of Tail Light No. 2 Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE REAR LIGHT SOCKET AND WIRE LH. Refer to  DISASSEMBLY [11/2020 - ] 

    Result: 

    NG 

    REPLACE REAR LIGHT ASSEMBLY LH. Refer to  REMOVAL [11/2020 - ] 

  20. CHECK LICENSE PLATE LIGHT ASSEMBLY RH 
    1. Disconnect the K8 license plate light assembly RH connector.
    2. Turn the light control switch tail position.
    3. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Tail Light No. 2 Fuse Taillight fuse Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Status of Tail Light No. 2 Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  23

    Result: 

    OK 

    See step  21

  21. CHECK LICENSE PLATE LIGHT ASSEMBLY LH 
    1. Disconnect the K7 license plate light assembly LH connector.
    2. Turn the light control switch tail position.
    3. Using the GTS, read the Data List.

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Tail Light No. 2 Fuse Taillight fuse Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 3 > Data List 

      Tester Display
      Status of Tail Light No. 2 Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE LICENSE PLATE LIGHT ASSEMBLY LH. Refer to  REMOVAL [11/2020 - ] 

    Result: 

    NG 

    See step  22

  22. CHECK HARNESS AND CONNECTOR (LICENSE PLATE LIGHT ASSEMBLY RH - LICENSE PLATE LIGHT ASSEMBLY LH) 
    1. Disconnect the K7 license plate light assembly LH connector.
    2. Disconnect the K8 license plate light assembly RH connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      K8-2 (E) - K7-1 (B) Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE LICENSE PLATE LIGHT ASSEMBLY RH. Refer to  REMOVAL [11/2020 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  23. CHECK HARNESS AND CONNECTOR (REAR LIGHT ASSEMBLY RH - NO. 2 SEMICONDUCTOR POWER INTEGRATION ECU) 
    1. Disconnect the cable from the negative (-) auxiliary battery terminal.
    2. Disconnect the K10 rear light assembly RH connector.
    3. Disconnect the K6 rear light assembly LH connector.
    4. Disconnect the K8 license plate light assembly RH connector.
    5. Disconnect the G102 No. 2 semiconductor power integration ECU connector.
    6. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      K10-1 (B) or G102-17 (TAIL) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 2 SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [11/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 12/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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