DTC B27A5-13: Front Floor Electrical Key Oscillator Circuit Open [11/2023 - ]: 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

Pre-procedure1

1. Disconnect the H138 certification ECU (smart key ECU assembly) connector.
2. Disconnect the H141 No. 1 indoor electrical key antenna assembly (front floor) connector.

   Procedure1

3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   H138-4 (CLG5) - H141-1 (ANTE5)	Always	Below 1 Ω
   H138-5 (CG5B) - H141-2 (CLGB)	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

   Post-procedure1

4. Connect the H138 certification ECU (smart key ECU assembly) connector.

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

1. Using an oscilloscope, check the waveform.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Component with harness connected (Certification ECU (Smart Key ECU Assembly))	*b	Waveform 1
   *c	For 30 seconds after any door closed	*d	After 30 seconds or more have elapsed since any door closed

   OK

   Tester Connection	Condition	Tool Setting	Specified Condition
   H138-4 (CLG5) - H138-29 (E)	Procedure: Ignition switch off Electrical key transmitter sub-assembly not inside vehicle Within 30 seconds of closing any door	5 V/DIV., 500 ms./DIV.	Pulse generation (See waveform 1)
   H138-5 (CG5B) - H138-29 (E)	Procedure: Ignition switch off Electrical key transmitter sub-assembly not inside vehicle Within 30 seconds of closing any door	5 V/DIV., 500 ms./DIV.	Pulse generation (See waveform 1)

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT FLOOR). Refer to  REMOVAL [10/2022 - ] 

Result: 

NG 

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [11/2023 - ]