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

1. Turn the engine 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 (front floor).

   OK

   Connectors are properly connected.

NG → CONNECT CONNECTORS PROPERLY 

OK: Go to next step 

1. Disconnect the A28 and D64 certification ECU (smart key ECU assembly) connectors.
2. Disconnect the D34 NO. 1 indoor electrical key antenna assembly (front floor) connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   D64-3 (CLG5) - D34-1 (ANTE5)	Always	Below 1 Ω
   D64-2 (CG5B) - D34-3 (CLGB)	Always	Below 1 Ω
   A28-11 (E) - Body ground	Always	Below 1 Ω
   D64-3 (CLG5) or D34-1 (ANTE5) - Body ground	Always	10 kΩ or higher
   D64-2 (CG5B) or D34-3 (CLGB) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Connect the A28 and D64 certification ECU (smart key ECU assembly) connectors.
   Fig 1: Checking Certification ECU (Smart Key ECU ASSEMBLY) And Waveform

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   TEXT IN ILLUSTRATION
   
   

   *1	Waveform	-	-
   *a	Component with harness connected (Certification ECU (smart key ECU assembly))	*b	Within approximately 30 seconds from when the door is closed
   *c	After approximately 30 seconds from when the door is closed	-	-

2. Connect the D34 NO. 1 indoor electrical key antenna assembly (front floor) connector.
3. Using an oscilloscope, check the waveform.

   OK

   Tester Connection	Condition	Tool Setting	Specified Condition
   D64-3 (CLG5) - A28-11 (E)	Procedure: Engine 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)
   D64-2 (CG5B) - A28-11 (E)	Procedure: Engine 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 NO. 1 indoor electrical key antenna assembly (front floor) with a new or known good 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 (NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT FLOOR) WAS DEFECTIVE)