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Inspection Procedure

  1. INSPECT FUSES (DEF, GAUGE, A/C) 
    1. Remove the DEF, GAUGE and A/C fuses from the main body ECU.
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      STANDARD RESISTANCE SPECIFICATIONS

      Item Condition Specified Condition
      DEF fuse Always Below 1 Ω
      GAUGE fuse Always Below 1 Ω
      A/C fuse Always Below 1 Ω
    3. Reinstall the fuses.

    NG: REPLACE FUSE 

    Fig 1: Identifying DEF, GAUGE And A/C Fuses
    G05403108Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to Next Step 

  2. CHECK HARNESS AND CONNECTOR (REAR WINDOW DEFOGGER WIRE BATTERY POSITIVE) 
    1. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Switch Condition Specified Condition
      N2-1 - Body ground Ignition switch ON
      Rear defogger switch ON      		 11 to 14 V

    NG:  Go to step  4

    Fig 2: Identifying N2 Connector Terminals
    G05403109Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to Next Step 

  3. CHECK HARNESS AND CONNECTOR (REAR WINDOW DEFOGGER WIRE CONNECTOR - BODY GROUND) 
    1. Disconnect the O8 rear window defogger wire connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Condition Specified Condition
      O8-1 - Body ground Always Below 1 Ω
    3. Reconnect the rear window defogger wire connector.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Fig 3: Identifying O8 Rear Window Defogger Wire Connector Terminals
    G05403110Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK : REPAIR REAR WINDOW DEFOGGER WIRE  (See REPAIR  )

  4. CHECK HARNESS AND CONNECTOR (REAR WINDOW DEFOGGER WIRE - MAIN BODY ECU) 
    1. Disconnect the 4F main body ECU connector.
    2. Disconnect the N2 rear window defogger wire connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Condition Specified Condition
      N2-1 - 4F-2 Always Below 1 Ω
      N2-1 - Body ground Always 10 kΩ or higher
    4. Reconnect the main body ECU connector.
    5. Reconnect the rear window defogger connector.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Fig 4: Identifying N2 Rear Window Defogger Wire Connector Terminals
    G05403111Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to Next Step 

  5. CHECK HARNESS AND CONNECTOR (REAR WINDOW DEFOGGER SYSTEM POWER SOURCE) 
    1. Disconnect the 4G main body ECU connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Switch Condition Specified Condition
      4G-1 - Body ground Ignition switch ON 11 to 14 V
    3. Reconnect the main body ECU connector.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Fig 5: Identifying 4G Main Body ECU Connector Terminals
    G05403112Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to Next Step 

  6. INSPECT MAIN BODY ECU (DEF RELAY) 
    Fig 6: Inspecting Main Body ECU (DEF Relay)
    G05403113Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Remove the main body ECU.
    2. Remove the GAUGE fuse from the main body ECU.
    3. Measure the resistance of the DEF relay.

      Standard resistance 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Condition Specified Condition
      4G-1 - 4F-2 When battery voltage absent 10 kΩ or higher
      4G-1 - 4F-2 When battery voltage applied to terminals 4Q-12 and GAUGE fuse (DEF relay side) Below 1 Ω
    4. Reinstall the fuse.
    5. Reinstall the main body ECU.

    NG: REPLACE MAIN BODY ECU 

    OK: Go to Next Step 

  7. CHECK HARNESS AND CONNECTOR (REAR WINDOW DEFOGGER SWITCH - MAIN BODY ECU) 
    1. Disconnect the G6 heater control connector.
    2. Disconnect the 4Q, 4S main body ECU connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Condition Specified Condition
      G6-2 (RDEF) - 4Q-12 Always Below 1 Ω
      G6-3 (IG+) - 4S-10 Always Below 1 Ω
      G6-2 (RDEF) - Body ground Always 10 kΩ or higher
      G6-3 (IG+) - Body ground Always 10 kΩ or higher
    4. Reconnect the heater control connector.
    5. Reconnect the main body ECU connector.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Fig 7: Identifying 4Q, 4S Main Body ECU Connector Terminals
    G05403114Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to Next Step 

  8. CHECK HARNESS AND CONNECTOR (HEATER CONTROL - BODY GROUND) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Condition Specified Condition
      G6-1 (E) - Body ground Always Below 1 Ω

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Fig 8: Identifying G6 Connector Terminals
    G05403115Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK : REPLACE HEATER CONTROL  (See REMOVAL )

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