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DTC B27A7: Open in Inside Luggage Compartment Electrical Key Oscillator Circuit [08/2013 - ]: Procedure

WARNING: This page is about a different car, the 2014 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK CONNECTOR CONNECTION 
    1. Turn the power switch off.
    2. Check that the connectors are properly connected to the certification ECU (smart key ECU assembly) and NO. 1 indoor electrical key antenna assembly (inside luggage compartment).

      OK

      Connectors are properly connected.

    NG → CONNECT CONNECTORS PROPERLY 

    OK: Go to next step 

  2. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY) 
    1. Disconnect the Q1 and H57 certification ECU (smart key ECU assembly) connectors.
    2. Disconnect the Q25 NO. 1 indoor electrical key antenna assembly (inside luggage compartment) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      Q1-4 (CLG7) - Q25-1 (ANTE7) Always Below 1 Ω
      Q1-3 (CG7B) - Q25-3 (CLGB) Always Below 1 Ω
      H57-1 (E) - Body ground Always Below 1 Ω
      Q1-4 (CLG7) or Q25-1 (ANTE7) - Body ground Always 10 kΩ or higher
      Q1-3 (CG7B) or Q25-3 (CLGB) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  3. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (OUTPUT TO NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY) 
    1. Connect the Q1 and H57 certification ECU (smart key ECU assembly) connectors.
      GTY406514Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *1 Waveform - -
      *a Component with harness connected
      (Certification ECU (smart key ECU assembly))      		 *b Before driver door lock sensor touched
      *c After driver door lock sensor touched - -
    2. Connect the Q25 NO. 1 indoor electrical key antenna assembly (inside luggage compartment) connector.
    3. Using an oscilloscope, check the waveform.

      OK

      Tester Connection Condition Tool Setting Specified Condition
      Q1-4 (CLG7) - H57-1 (E) Procedure:
      1. Power switch off
      2. Electrical key transmitter sub-assembly not inside vehicle
      3. All doors closed
      4. Driver door lock sensor not touched → touched
      		 2 V/DIV., 500 ms/DIV. Pulse generation (See waveform)
      Q1-3 (CG7B) - H57-1 (E) Procedure:
      1. Power switch off
      2. Electrical key transmitter sub-assembly not inside vehicle
      3. All doors closed
      4. Driver door lock sensor not touched → touched
      		 2 V/DIV., 500 ms/DIV. Pulse generation (See waveform)

    NG → See step   7 

    OK: Go to next step 

  4. REPLACE NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (INSIDE LUGGAGE COMPARTMENT) 
    1. Temporarily replace the NO. 1 indoor electrical key antenna assembly (inside luggage compartment) with a new or known good one. Refer to REMOVAL [08/2013 - ] .

    NEXT: Go to next step 

  5. CLEAR DTC 
    1. Clear the DTCs. Refer to DTC CHECK / CLEAR [08/2013 - ] .

    NEXT: Go to next step 

  6. CHECK FOR DTC 
    1. Check for DTCs. Refer to DTC CHECK / CLEAR [08/2013 - ] .

      OK

      DTC B27A7 is not output.

    NG → See step   7 

    OK → END (NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (INSIDE LUGGAGE COMPARTMENT) WAS DEFECTIVE) 

  7. REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [08/2013 - ] 
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