DTC B27A7: Open in Inside Luggage Compartment Electrical Key Oscillator Circuit [12/2019 - 11/2023]: Procedure

1. Check that the connectors are properly connected to the certification ECU (smart key ECU assembly) and No. 3 indoor electrical key antenna assembly (inside luggage compartment).

   OK

   Connectors are properly connected.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

CONNECT CONNECTORS PROPERLY 

Result: 

OK 

See step  2

1. Disconnect the M5 certification ECU (smart key ECU assembly) connector.
2. Disconnect the U1 No. 3 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
   M5-11 (CLG7) - U1-1 (ANTE7)	Always	Below 1 Ω
   M5-10 (CG7B) - U1-3 (CLGB)	Always	Below 1 Ω

4. Connect the M5 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
   M5-11 (CLG7) - H48-18 (E)	Procedure: Ignition 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)
   M5-10 (CG7B) - H48-18 (E)	Procedure: Ignition 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)

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE NO. 3 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (INSIDE LUGGAGE COMPARTMENT). Refer to  REMOVAL [12/2019 - ] 

Result: 

NG 

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [12/2019 - 11/2023]