DTC B27A8 Trunk/Rear Gate External Antenna Open

DTC DETECTING CONDITION:

When open circuit occurs in the harness between Keyless Access Control Module and rear exterior antenna.

TROUBLE SYMPTOM:

Keyless access system does not function.

(Cannot unlock using rear gate opener button.)

CAUTION: For replacement procedure of Keyless Access Control Module, refer to the "REGISTRATION MANUAL FOR IMMOBILIZER" provided as a separate volume.

WIRING DIAGRAM:

Keyless access system <Ref. to WIRING DIAGRAM , Keyless Access System.>

Fig 1: Trunk/Rear Gate External Antenna Open - Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

Step	Check	Yes	No
1 CHECK LAN SYSTEM. Inspect LAN system. <Ref. to PROCEDURE , Basic Diagnostic Procedure.>	Is the check result OK?	Go to step 2 .	Perform the inspection according to the diagnosis for LAN system.
2 CHECK CONNECTOR. Disconnect the Keyless Access Control Module connector. Disconnect the rear exterior antenna connector. Check the connector.	Is the check result OK?	Go to step 3 .	Repair or replace the connector.
3 CHECK HARNESS (OPEN CIRCUIT). Using a tester, measure the resistance between the Keyless Access Control Module connector and rear external antenna connector. Connector & terminal (B573) No. 2 - (AD23) No. 1: (B573) No. 1 - (AD23) No. 2:	Is the resistance less than 1 Ω?	Go to step 4 .	Repair or replace the open circuit of harness.
4 CHECK HARNESS (GROUND SHORT CIRCUIT). Using a tester, measure the resistance between the Keyless Access Control Module connector and chassis ground. Connector & terminal (B573) No. 2 - Chassis ground: (B573) No. 1 - Chassis ground:	Is the resistance 10 kΩ or more?	Go to step 5 .	Repair or replace the short circuit of the harness.
5 CHECK DTC. Connect the Keyless Access Control Module connector. Using the Subaru Select Monitor, clear the memory. <Ref. to CLEAR MEMORY MODE .> Read the DTC using Subaru Select Monitor. <Ref. to READ DIAGNOSTIC TROUBLE CODE (DTC) .>	Is DTC B27A8 displayed?	Go to step 6 .	Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again. NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
6 CHECK REAR EXTERIOR ANTENNA. Replace the rear exterior antenna with the rear interior antenna. <Ref. to Keyless Access Indoor Antenna .> <Ref. to Keyless Access Outdoor Antenna .> Using the Subaru Select Monitor, clear the memory. <Ref. to CLEAR MEMORY MODE .> Read the DTC using Subaru Select Monitor. <Ref. to READ DIAGNOSTIC TROUBLE CODE (DTC) .>	Is DTC B27A8 displayed?	Replace the Keyless Access Control Module. <Ref. to Keyless Access Control Module .>	Malfunction occurred in the rear external antenna.