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Home >> Toyota >> 2013 >> Prius Plug-in >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 129 (Lighting System (Diagnostic Codes & Circuit Tests) (Except Plug-In)) >> Lighting System >> Circuit Tests >> Back-up Light Circuit >> Procedure
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Back-up Light Circuit: Procedure

WARNING: This page is about a different variant/trim than selected.
  1. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - BATTERY AND BODY GROUND) 
    1. Disconnect the 1H integration relay connector.
      Fig 1: Identifying Integration Relay Connector Terminals
      GTY225517Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage and resistance according to the value(s) in the table below.

      Standard Voltage

      Tester Connector Condition Specified Condition
      1H-7 (BATT) - Body ground Always 11 to 14 V

      Standard Resistance

      Tester Connection Condition Specified Condition
      1H-3 (GND2) - Body ground Always Below 1 Ω
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Integration Relay)
    3. Disconnect the 1G integration relay connector.
      Fig 2: Identifying 1G No. 1 Integration Relay Connector
      GTY221746Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      1G-22 (GND1) - Body ground Always Below 1 Ω
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Integration Relay)

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  2. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - POWER MANAGEMENT CONTROL ECU) 
    1. Reconnect the A21 power management control ECU connector.
    2. Disconnect the 1G integration relay connector.
    3. Disconnect the A21 power management control ECU connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      1G-13 (BKUP) - A21-15 (BL) Always Below 1 Ω
      1G-13 (BKUP) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  3. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - REAR COMBINATION LIGHT ASSEMBLY) 
    1. Disconnect the 1G integration relay connector.
    2. Disconnect the S18 or R17 rear combination light assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      1G-3 (BCK1) - S18-4 (B) Always Below 1 Ω
      1G-3 (BCK1) - R17-4 (B) Always Below 1 Ω
      1G-3 (BCK1) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  4. REPLACE INTEGRATION NO. 1 RELAY 
    1. Temporarily replace the integration relay with a new or normally functioning one. Refer to REMOVAL
    2. Check that the back-up lights operate normally.

      OK

      The back-up lights operate normally.

    NG → See step   5 

    OK → END 

  5. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE 
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