Toyota 4Runner: Open in Outside Luggage Compartment Electrical Key Antenna Circuit (B27A8)

Toyota 4Runner Service Manual / Vehicle Interior / Theft Deterrent / Keyless Entry / Smart Key System(for Entry Function) / Open in Outside Luggage Compartment Electrical Key Antenna Circuit (B27A8)

DESCRIPTION

The certification ECU generates a request signal and transmits the signal to the electrical key antenna (outside luggage). The electrical key antenna (outside luggage) detects that the electrical key is brought close to the vehicle, and when a request signal is received from within 1.0 m (3.28 ft.) of the back door, the signal is transmitted. DTC B27A8 is stored by the certification ECU when an open circuit is detected in the circuit between the certification ECU and electrical key antenna (outside luggage) (CLG8 - CLG5, CG8B - CLGB).

DTC Code	DTC Detection Condition	Trouble Area
B27A8	An open circuit is detected in the circuit between the certification ECU and electrical key antenna (outside luggage) (CLG8 - CLG5, CG8B - CLGB).	Harness or connector Electrical key antenna (outside luggage) 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 electrical key antenna (outside luggage).

OK:

Connectors are properly connected.

CONNECT CONNECTORS PROPERLY

2.	CHECK HARNESS AND CONNECTOR (ELECTRICAL KEY ANTENNA - CERTIFICATION ECU)

(a) Disconnect the N21 antenna connector.

(b) Disconnect the F78 ECU connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
N21-1 (CLG5) - F78-19 (CLG8)	Always	Below 1 Ω
N21-2 (CLGB) - F78-20 (CG8B)	Always	Below 1 Ω
F78-19 (CLG8) - Body ground	Always	10 kΩ or higher
F78-20 (CG8B) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	INSPECT ELECTRICAL KEY ANTENNA (OUTSIDE LUGGAGE)

(a) Remove the outside electrical key antenna (outside luggage) (See page ).

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
1 (CLG5) - 2 (CLGB)	Always	Below 1 Ω

REPLACE ELECTRICAL KEY ANTENNA (OUTSIDE LUGGAGE)

4.	REPLACE CERTIFICATION ECU

(a) Temporarily replace the certification ECU with a new one (See page ).

5.	CHECK FOR DTC

(a) Clear the DTCs (See page ).

(b) Check for DTCs (See page ).

OK:

DTC B27A8 is not output.

END (CERTIFICATION ECU IS DEFECTIVE)

REPLACE ELECTRICAL KEY ANTENNA (OUTSIDE LUGGAGE)

Open in Inside Luggage Compartment Electrical Key Oscillator Circuit (B27A7)

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