DTC B27A1: Driver Side External Antenna Open

DTC detecting condition: 

When open circuit occurs in the harness between keyless access control module and driver's side front door outer handle.

Trouble symptom: 

The keyless access with push button start system does not operate.

Wiring diagram: 

Keyless access with push button start system Ref. to WIRING SYSTEM>KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM>WIRING DIAGRAM

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK LAN SYSTEM  .

   Inspect LAN system. Ref. to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE

   Is the check result OK?

   Yes  : Go to  2.

   No  : Perform the inspection according to the diagnosis for LAN system.

2. CHECK CONNECTOR  .
   1. Disconnect the connector from the keyless access control module.
   2. Disconnect the connector from the front door outer handle.
   3. Check the connector.

   Is the check result OK?

   Yes  : Go to  3.

   No  : Repair or replace the connector.

3. CHECK POWER SUPPLY CIRCUIT  .

   Using a tester, measure the voltage between the keyless access control module connector and chassis ground.

   Connector & terminal 

   (i91) No. 4 (+) - Chassis ground (-):

   Is the voltage 9.5 - 16 V?

   Yes  : Go to  4.

   No  : Check the power supply circuit.

4. CHECK HARNESS (OPEN CIRCUIT)  .

   Using a tester, measure the resistance between the keyless access control module connector and front door outside handle connector, and between keyless access control module connector and chassis ground.

   Connector & terminal 

   (i92) No. 5 - (Df36) No. 1:

   (i92) No. 6 - (Df36) No. 2:

   (i92) No. 17 - Chassis ground:

   (i91) No. 20 - Chassis ground:

   Is the resistance less than 1 Ω?

   Yes  : Go to  5.

   No  : Repair or replace the open circuit of harness.

5. CHECK HARNESS (GROUND SHORT CIRCUIT)  .

   Using a tester, measure the resistance between the keyless access control module connector and chassis ground.

   Connector & terminal 

   (i92) No. 5 - Chassis ground:

   (i92) No. 6 - Chassis ground:

   Is the resistance 10 kΩ or more?

   Yes  : Go to  6.

   No  : Repair or replace the short circuit of the harness.

6. CHECK DTC  .
   1. Connect the disconnected connectors.
   2. Turn the ignition switch to ON.
   3. Using the Subaru Select Monitor, perform the clear memory of [Keyless Access with Push Button Start (Collation)]. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY
   4. Read the DTC of [Keyless Access with Push Button Start (Collation)] using the Subaru Select Monitor. Ref. to KEYLESS ACCESS WITH PUSH BUTTON START (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) 

   Is DTC B27A1 displayed? (Current code)

   Yes  : Go to  7.

   No  : 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. 

7. CHECK FRONT DOOR OUTER HANDLE  .
   1. Turn the ignition switch to OFF.
   2. Replace the driver's side front door outer handle with the passenger's front door outer handle. Ref. to SECURITY AND LOCKS>DOOR OUTER HANDLE>REMOVAL
   3. Turn the ignition switch to ON.
   4. Using the Subaru Select Monitor, perform the clear memory of [Keyless Access with Push Button Start (Collation)]. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY
   5. Read the DTC of [Keyless Access with Push Button Start (Collation)] using the Subaru Select Monitor. Ref. to KEYLESS ACCESS WITH PUSH BUTTON START (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) 

   Is DTC B27A1 displayed? (Current code)

   Yes  : Replace the keyless access control module. Ref. to SECURITY AND LOCKS>KEYLESS ACCESS CONTROL MODULE>REMOVAL

   No  : Replace the driver's side front door outer handle. Ref. to SECURITY AND LOCKS>DOOR OUTER HANDLE>REMOVAL