Toyota 4Runner: Open in Rear Floor Electrical Key Oscillator Circuit (B27A6)

Toyota 4Runner Service Manual / Vehicle Interior / Theft Deterrent / Keyless Entry / Smart Key System(for Entry Function) / Open in Rear Floor Electrical Key Oscillator Circuit (B27A6)

DESCRIPTION

The certification ECU generates a request signal and transmits the signal to the indoor No. 2 electrical key antenna (rear floor). The indoor No. 2 electrical key antenna (rear floor) detects that the electrical key is inside the vehicle and transmits the request signal received from the certification ECU. DTC B27A6 is stored by the certification ECU when an open circuit is detected in the circuit between the certification ECU and indoor No. 2 electrical key antenna (rear floor) (CLG6 - CLG4, CG6B - CLGB).

DTC Code	DTC Detection Condition	Trouble Area
B27A6	An open circuit is detected in the circuit between the certification ECU and indoor No. 2 electrical key antenna (rear floor) (CLG6 - CLG4, CG6B - CLGB).	Harness or connector Indoor No. 2 electrical key antenna (rear floor) Certification ECU

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

The smart key system (for Entry Function) uses a multiplex communication system (LIN communication system) and the CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting (See page ). Troubleshoot the smart key system
(for Entry Function) after confirming that the communication systems are functioning properly.
When using the Techstream with the engine switch off to troubleshoot: Connect the Techstream to the DLC3 and turn a courtesy light switch on and off at 1.5-second intervals until communication between the Techstream and vehicle begins.
Before replacing the certification ECU, refer to the engine immobiliser system (w/ Smart Key System) (See page ).

PROCEDURE

1.	CHECK CONNECTOR CONNECTION

(a) Turn the engine switch off.

(b) Check that the connectors are properly connected to the certification ECU and indoor No. 2 electrical key antenna (rear floor).

OK:

Connectors are properly connected.

CONNECT CONNECTORS PROPERLY

2.	CHECK HARNESS AND CONNECTOR (INDOOR NO. 2 ELECTRICAL KEY ANTENNA - CERTIFICATION ECU)

(a) Disconnect the O9 antenna connector.

(b) Disconnect the F79 ECU connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
O9-1 (CLG4) - F79-24 (CLG6)	Always	Below 1 Ω
O9-3 (CLGB) - F79-25 (CG6B)	Always	Below 1 Ω
F79-24 (CLG6) - Body ground	Always	10 kΩ or higher
F79-25 (CG6B) - Body ground	Always	10 kΩ or higher
F79-15 (E) - Body ground	Always	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	CHECK CERTIFICATION ECU

(a) Measure the voltage according to the value(s) in the table below.

Text in Illustration

Component with harness connected

(Certification ECU)

OK:

Tester Connection	Switch Condition	Specified Condition
F79-24 (CLG6) - F79-15 (E)	Engine switch off, all doors closed, key not in cabin and lock sensor off → on	No pulse generation → Pulse generation
F79-25 (CG6B) - F79-15 (E)	Engine switch off, all doors closed, key not in cabin and lock sensor off → on	No pulse generation → Pulse generation

REPLACE CERTIFICATION ECU

4.	REPLACE INDOOR NO. 2 ELECTRICAL KEY ANTENNA ASSEMBLY (REAR FLOOR)

(a) Temporarily replace the indoor No. 2 electrical key antenna (rear floor) with a new or normally functioning one (See page ).

5.	CHECK FOR DTC

(a) Clear the DTCs (See page ).

(b) Check for DTCs (See page ).

OK:

DTC B27A6 is not output.

END (INDOOR NO. 2 ELECTRICAL KEY ANTENNA ASSEMBLY IS DEFECTIVE)

REPLACE CERTIFICATION ECU

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