DTC B27A5: Open in Front Floor Electrical Key Oscillator Circuit: Procedure

1. Turn the power switch off.
2. Check that the connectors are properly connected to the certification ECU (smart key ECU assembly) and indoor electrical key oscillator (front floor).

   OK

   Connectors are properly connected.

NG → CONNECT CONNECTORS PROPERLY 

OK: Go to next step 

1. Disconnect the C19 certification ECU (smart key ECU assembly) connector.
2. Disconnect the C17 indoor electrical key oscillator (front floor) connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   C19-7 (CLG5) - C17-1 (ANTE5)	Always	Below 1 Ω
   C19-8 (CG5B) - C17-3 (CLGB)	Always	Below 1 Ω
   C19-15 (E) - Body ground	Always	Below 1 Ω
   C19-7 (CLG5) or C17-1 (ANTE5) - Body ground	Always	10 kΩ or higher
   C19-8 (CG5B) or C17-3 (CLGB) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Connect the C19 certification ECU (smart key ECU assembly) connector.
2. Connect the C17 indoor electrical key oscillator (front floor) connector.
   Fig 1: Identifying Certification ECU (Smart Key ECU Assembly) Connector Terminals With Waveform

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   TEXT IN ILLUSTRATION
   
   

   *a	Component with harness connected (Certification ECU - Smart Key ECU Assembly)	*b	Waveform
   *c	Door open	*d	From approximately 30 seconds after door is closed

3. Using an oscilloscope, check the waveform.

   OK

   Tester Connection	Condition	Tool Setting	Specified Condition
   C19-7 (CLG5) - C19-15 (E)	Procedure: Power switch off Electrical key transmitter sub-assembly not inside vehicle Door is open Door is closed Within 30 seconds	2 V/DIV., 500 ms/DIV.	Pulse generation (See waveform)
   C19-8 (CG5B) - C19-15 (E)	Procedure: Power switch off Electrical key transmitter sub-assembly not inside vehicle Door is open Door is closed Within 30 seconds	2 V/DIV., 500 ms/DIV.	Pulse generation (See waveform)

NG → See step   7 

OK: Go to next step 

1. Temporarily replace the indoor electrical key oscillator (front floor) with a new or normally functioning one. Refer to REMOVAL .

NEXT: Go to next step 

1. Clear the DTCs. Refer to DTC CHECK / CLEAR .

NEXT: Go to next step 

1. Check for DTCs. Refer to DTC CHECK / CLEAR .

   OK

   DTC B27A5 is not output.

NG → See step   7 

OK → END (INDOOR ELECTRICAL KEY OSCILLATOR (FRONT FLOOR) WAS DEFECTIVE)