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Home >> Lexus >> 2008 >> IS 350 >> Repair and Diagnosis >> Accessories & Equipment >> Exterior Lights >> Lighting >> Lighting System >> Taillight Circuit >> Inspection Procedure

Inspection Procedure

NOTE: Before proceeding to the following flowchart, check that the fuses are not blown and that the bulbs are not burned out.
  1. CHECK TAILLIGHT (OPERATION) 
    1. Turn the engine switch on (IG).
    2. When the taillight switch is operated, check that the following lights illuminate.

      HINT:

      • The front lights (front side marker lights and parking lights) share the same drive circuit. Therefore, if one of the front lights does not come on, there may be a problem in the circuit between the FR TAIL relay and bulb, or the circuit between the bulb and body ground. Inspect those circuits to identify the problem.
      • The rear lights (taillights, license plate lights, and side marker lights) share the same drive circuit. Therefore, if one of the rear lights does not come on, there may be a problem in the circuit between the TAIL relay and the bulb or LED, or the circuit between the bulb or LED and body ground. Inspect those circuits to identify the problem.

      Result 

      RESULT CHART

      Result Proceed to
      Neither front nor rear lights illuminate A
      Front lights (front side marker lights and parking lights) do not illuminate B
      Rear lights (taillights, license plate lights, and side marker lights) do not illuminate C

    B: Go to step 2 

    C:  Go to step  6

    A: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN  PROBLEM SYMPTOMS TABLE  

  2. PERFORM ACTIVE TEST BY TECHSTREAM 
    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 / Body No. 5 / Active Test.
    5. Check the operation.

      Body No. 5 (Front Controller); 

      DIAGNOSTIC NOTE

      Tester Display Test Part Control Range Diagnostic Note
      Clearance Light Operation Clearance light (Front side marker lights and parking lights) ON / OFF -

      OK: 

      Front side marker lights and parking lights illuminate. 

    NG: Go to step 3 

    OK: REPLACE ENGINE ROOM NO. 2 R/B (FRONT CONTROLLER) 

  3. CHECK HARNESS AND CONNECTOR (HEADLIGHT - BODY GROUND) 

    HINT:

    Perform the following inspection on either the LH or RH side.

    1. Disconnect the B2 or B12 headlight connector.
    2. Measure the resistance according to the value (s) in the table below.

      Standard resistance: 

      RH side 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      B2-5 (E) - Body ground Always Below 1 Ω
      B2-8 (E) - Body ground Always Below 1 Ω

      LH side 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      B12-5 (E) - Body ground Always Below 1 Ω
      B12-8 (E) - Body ground Always Below 1 Ω
      3. Fig 1: Identifying Harness And Connector (Headlight - Body Ground)
      G05832113Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

  4. CHECK HARNESS AND CONNECTOR (HEADLIGHT - BODY GROUND) 

    HINT:

    Perform the following inspection on either the LH or RH side.

    1. Disconnect the B2 or B12 headlight connector.
    2. Measure the voltage according to the value (s) in the table below.

      Standard voltage: 

      RH side 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      B2-6 (B) - Body ground Engine switch off Below 1 V
      B2-6 (B) - Body ground Engine switch on (IG) and taillights on 10 to 14 V
      B2-7 (B) - Body ground Engine switch off Below 1 V
      B2-7 (B) - Body ground Engine switch on (IG) and taillights on 10 to 14 V

      LH side 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      B12-6 (B) - Body ground Engine switch off Below 1 V
      B12-6 (B) - Body ground Engine switch on (IG) and taillights on 10 to 14 V
      B12-7 (B) - Body ground Engine switch off Below 1 V
      B12-7 (B) - Body ground Engine switch on (IG) and taillights on 10 to 14 V
      Fig 2: Identifying Harness And Connector (Headlight - Body Ground)
      G05832114Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: Go to step 5 

    OK: REPLACE HEADLIGHT ASSEMBLY 

  5. CHECK HARNESS AND CONNECTOR (HEADLIGHT - ENGINE ROOM NO. 2 R/B) 

    HINT:

    Perform the following inspection on either the LH or RH side.

    1. Disconnect the B2 or B12 headlight connector.
    2. Disconnect the 2G engine room No. 2 R/B connector.
    3. Measure the resistance according to the value (s) in the table below.

      Standard resistance: 

      RH side 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      B2-6 (B) - 2G-10 Always Below 1 Ω
      B2-6 (B) - Body ground Always 10 kΩ or higher
      B2-7 (B) - 2G-8 Always Below 1 Ω
      B2-7 (B) - Body ground Always 10 kΩ or higher

      LH side 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      B12-6 (B) - 2G-11 Always Below 1 Ω
      B12-6 (B) - Body ground Always 10 kΩ or higher
      B12-7 (B) - 2G-9 Always Below 1 Ω
      B12-7 (B) - Body ground Always 10 kΩ or higher
      4. Fig 3: Identifying Harness And Connector (Headlight - Engine Room No. 2 R/B)
      G05832115Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE ENGINE ROOM NO. 2 R/B (FRONT CONTROLLER) 

  6. PERFORM ACTIVE TEST BY TECHSTREAM 
    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 / Body / Active Test.
    5. Check the operation.

      Body (Main Body ECU RH): 

      DIAGNOSTIC NOTE

      Tester Display Test Part Control Range Diagnostic Note
      Tail Light Taillights (taillights, license plate lights and side marker lights) ON / OFF -

      OK: 

      Taillights, license plate lights and side marker lights illuminate. 

      Result 

      RESULT CHART

      Result Proceed to
      Inner taillights do not illuminate A
      Outer taillights and side marker lights do not illuminate B
      License plate lights do not Illuminate C
      All rear lights illuminate D
      All rear lights do not illuminate E

      HINT:

      If the outer taillights illuminate normally, but the side marker lights do not illuminate, or vice versa, there is an open circuit in the rear combination light.

    B:  Go to step  9

    C:  Go to step  11

    D: REPLACE MAIN BODY ECU RH (COWL SIDE J/B RH) 

    E:  Go to step  15

    A: Go to Next Step 

  7. CHECK HARNESS AND CONNECTOR (INNER TAILLIGHT - BODY GROUND) 

    HINT:

    Perform the following inspection on either the LH or RH side.

    1. Disconnect the Q46 or Q40 inner taillight connector.
    2. Measure the resistance according to the value (s) in the table below.

      Standard resistance: 

      RH side 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      Q46-3 - Body ground Always Below 1 Ω

      LH side 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      Q40-3 - Body ground Always Below 1 Ω
      3. Fig 4: Identifying Harness And Connector (Inner Taillight - Body Ground)
      G05832116Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

  8. CHECK HARNESS AND CONNECTOR (INNER TAILLIGHT - MAIN BODY ECU LH) 

    HINT:

    Perform the following inspection on either the LH or RH side.

    1. Disconnect the Q46 or Q40 inner taillight connector.
    2. Measure the voltage according to the value (s) in the table below.

      Standard voltage: 

      RH side 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      Q46-1 - Body ground Engine switch off Below 1 V
      Q46-1 - Body ground Engine switch on (IG) and taillights on 10 to 14 V

      LH side 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      Q40-1 - Body ground Engine switch off Below 1 V
      Q40-1 - Body ground Engine switch on (IG) and taillights on 10 to 14 V
      Fig 5: Identifying Harness And Connector (Inner Taillight - Main Body ECU LH)
      G05832117Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE INNER COMBINATION LIGHT 

  9. CHECK HARNESS AND CONNECTOR (OUTER TAILLIGHT - BODY GROUND) 

    HINT:

    Perform the following inspection on either the LH or RH side.

    1. Disconnect the Q51 or Q50 outer taillight connector.
    2. Measure the resistance according to the value (s) in the table below.

      Standard resistance: 

      RH side 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      Q51-6 (E) - Body ground Always Below 1 Ω

      LH side 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      Q50-6 (E) - Body ground Always Below 1 Ω
      Fig 6: Identifying Harness And Connector (Outer Taillight - Body Ground)
      G05832118Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

  10. CHECK HARNESS AND CONNECTOR (OUTER TAILLIGHT - MAIN BODY ECU LH) 

    HINT:

    Perform the following inspection on either the LH or RH side.

    1. Disconnect the Q51 or Q50 outer taillight connector.
    2. Measure the voltage according to the value (s) in the table below.

      Standard voltage: 

      RH side 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      Q51-3 - Body ground Engine switch off Below 1 V
      Q51-3 - Body ground Engine switch on (IG) and taillights on 10 to 14 V
      Fig 7: Identifying Harness And Connector (Outer Taillight - Main Body ECU LH)
      G05832119Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      LH side 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      Q50-3 - Body ground Engine switch off Below 1 V
      Q50-3 - Body ground Engine switch on (IG) and taillights on 10 to 14 V

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE OUTER COMBINATION LIGHT 

  11. CHECK HARNESS AND CONNECTOR (LICENSE PLATE LIGHT LH - BODY GROUND) 

    HINT:

    Perform the following inspection on the LH side.

    1. Disconnect the Q47 license plate light LH connector.
    2. Measure the resistance according to the value (s) in the table below.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      Q47-2 (E) - Body ground Always Below 1 Ω
      3. Fig 8: Identifying Q47 License Plate Light LH Connector
      G05832120Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

  12. CHECK HARNESS AND CONNECTOR (LICENSE PLATE LIGHT RH - MAIN BODY ECU LH) 

    HINT:

    Perform the following inspection on the RH side.

    1. Disconnect the Q44 license plate light RH connector.
    2. Measure the voltage according to the value (s) in the table below.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      Q44-1 (B) - Body ground Engine switch off Below 1 V
      Q44-1 (B) - Body ground Engine switch on (IG) and taillights on 10 to 14 V
      3. Fig 9: Identifying Q44 License Plate Light RH Connector
      G05832121Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

  13. CHECK HARNESS AND CONNECTOR (LICENSE PLATE LIGHT LH - LICENSE PLATE LIGHT LH) 

    HINT:

    Perform the following inspection on the LH side.

    1. Connect the Q44 license plate light RH connector.
    2. Disconnect the Q47 license plate light LH connector.
    3. Measure the voltage according to the value (s) in the table below.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      Q47-1 (B) - Body ground Engine switch off Below 1 V
      Q47-1 (B) - Body ground Engine switch on (IG) and taillights on 10 to 14 V
      4. Fig 10: Identifying Q47 License Plate Light LH Connector
      G05832122Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: Go to step 14 

    OK: REPLACE LICENSE PLATE LIGHT (LH SIDE) 

  14. CHECK HARNESS AND CONNECTOR (LICENSE PLATE LIGHT LH - LICENSE PLATE LIGHT RH) 
    1. Disconnect the Q44 license plate light RH connector.
    2. Disconnect the Q47 license plate light LH connector.
    3. Measure the resistance according to the value (s) in the table below.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      Q44-2 (E) - Q47-1 (B) Always Below 1 Ω
      Q44-2 (E) - Body ground Always 10 kΩ or higher
      4. Fig 11: Identifying Harness And Connector (License Plate Light LH - License Plate Light RH)
      G05832123Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE LICENSE PLATE LIGHT (RH SIDE) 

  15. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU RH - BODY GROUND) 
    1. Disconnect the RD main body ECU RH connector.
    2. Measure the voltage according to the value (s) in the table below.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      RD-1 (TRLY) - Body ground Always 10 to 14 V
      3. Fig 12: Identifying RD Main Body ECU RH Connector
      G05832124Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

  16. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU RH - MAIN BODY ECU LH) 
    1. Connect the RD main body ECU RH connector.
    2. Measure the voltage according to the value (s) in the table below.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      RD-1 (TRLY) - Body ground Engine switch off Below 1 V
      RD-1 (TRLY) - Body ground Engine switch on (IG) and taillights on 10 to 14 V
      3. Fig 13: Identifying RD Main Body ECU RH Connector
      G05832125Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE MAIN BODY ECU RH (COWL SIDE J/B RH) 

    OK: Go to Next Step 

  17. INSPECT MAIN BODY ECU LH (COWL SIDE J/B LH) 
    1. Disconnect the LJ main body ECU LH connector.
    2. Measure the voltage according to the value (s) in the table below.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      LJ-24 - Body ground Engine switch off Below 1 V
      LJ-24 - Body ground Engine switch on (IG) and taillights on 10 to 14 V
      3. Fig 14: Identifying LJ Main Body ECU LH Connector
      G05832126Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE MAIN BODY ECU LH (COWL SIDE J/B LH) 

    OK: REPAIR OR REPLACE HARNESS OR CONNECTOR (MAIN BODY ECU LH - EACH REAR LIGHT) 

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