DTC B27A5: Open in Front Floor Electrical Key Oscillator Circuit [11/2015 - ]: Procedure

1. 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.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

CONNECT CONNECTORS PROPERLY 

Result: 

OK 

See step  2

1. Disconnect the F1 certification ECU (smart key ECU assembly) connector.
2. Disconnect the F46 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
   F1-8 (CLG5) - F46-1 (ANTE5)	Always	Below 1 Ω
   F1-9 (CG5B) - F46-3 (CLGB)	Always	Below 1 Ω
   F1-18 (E) - Body ground	Always	Below 1 Ω
   F1-8 (CLG5) or F46-1 (ANTE5) - Body ground	Always	10 kΩ or higher
   F1-9 (CG5B) or F46-3 (CLGB) - Body ground	Always	10 kΩ or higher

4. Reconnect the F1 certification ECU (smart key ECU assembly) connector.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Using an oscilloscope, check the waveform.

   OK

   Tester Connection	Condition	Tool Setting	Specified Condition
   F1-8 (CLG5) - F1-18 (E)	Procedure: Power switch off Electrical key transmitter sub-assembly not inside vehicle Within 30 seconds of closing any door	2 V/DIV., 500 ms/DIV.	Pulse generation (See waveform 1)
   F1-9 (CG5B) - F1-18 (E)	Procedure: Power switch off Electrical key transmitter sub-assembly not inside vehicle Within 30 seconds of closing any door	2 V/DIV., 500 ms/DIV.	Pulse generation (See waveform 1)

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [11/2015 - 12/2018]  , or refer to  REMOVAL [12/2018 - 07/2020]  , or refer to  REMOVAL [07/2020 - ] 

Result: 

OK 

See step  4

1. Temporarily replace the No. 1 indoor electrical key antenna assembly (front floor) with a new or known good one.

   HINT: 

   Refer to REMOVAL [11/2015 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  5

1. Clear the DTCs.

   Body Electrical > Smart Key > Clear DTCs 

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  6

1. Check for DTCs.

   Body Electrical > Smart Key > Trouble Codes 

   Result

   Result	Proceed to
   B27A5 is not output	A
   B27A5 is output	B

Result: 

A 

END (NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT FLOOR) WAS DEFECTIVE) 

Result: 

B 

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [11/2015 - 12/2018]  , or refer to  REMOVAL [12/2018 - 07/2020]  , or refer to  REMOVAL [07/2020 - ]