DTC B27A9: Charging Lid External Antenna Open

DTC detecting condition: 

When open circuit occurs in the harness between keyless access Control Module and charger lid exterior antenna.

Trouble symptom: 

Keyless access system does not function.

(With the doors locked, the charger lid does not open or the charger port can not be locked/unlocked even if user has the access key.)

Wiring diagram: 

• Keyless access with push button start system Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM>WIRING DIAGRAM .
• Charging system Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>CHARGING SYSTEM>WIRING DIAGRAM .

  Courtesy of SUBARU OF AMERICA, INC.

  CAUTION:

  • For replacement procedure of keyless access Control Module, refer to the "REGISTRATION MANUAL FOR IMMOBILIZER" provided as a separate volume.
  • Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to KEYLESS ACCESS WITH PUSH BUTTON START (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION .

1. CHECK LAN SYSTEM  .

   Perform the diagnosis for LAN system. Ref. to LAN SYSTEM (DIAGNOSTICS (HEV)>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. Turn the ignition switch to OFF.
   2. Disconnect the keyless access Control Module connector.
   3. Disconnect the charger lid exterior antenna connector.
   4. 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 

   (i75) 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 charger lid exterior antenna connector, and between keyless access Control Module connector and chassis ground.

   Connector & terminal 

   (i241) No. 10 - (R522) No. 1:

   (i241) No. 11 - (R522) No. 2:

   (i241) No. 17 - Chassis ground:

   (i75) 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 

   (i241) No. 10 - Chassis ground:

   (i241) No. 11 - 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 keyless access Control Module connector.
   2. Using the Subaru Select Monitor, perform the clear memory of [Keyless Access with Push Button Start]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
   3. Read the DTC of [Keyless Access with Push Button Start] using the Subaru Select Monitor. Ref. to KEYLESS ACCESS WITH PUSH BUTTON START (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B27A9 displayed? (Current malfunction)

   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 KEYLESS ACCESS Control Module  .
   1. Short the terminals ((i241) No. 10, (i241) No. 11) for the charger lid exterior antenna of the keyless access Control Module. Ref. to SECURITY AND LOCKS>KEYLESS ACCESS CONTROL MODULE .
   2. Using the Subaru Select Monitor, perform the clear memory of [Keyless Access with Push Button Start]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
   3. Read the DTC of [Keyless Access with Push Button Start] using the Subaru Select Monitor. Ref. to KEYLESS ACCESS WITH PUSH BUTTON START (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B27A9 displayed? (Current malfunction)

   Yes  : Replace the keyless access Control Module. Ref. to SECURITY AND LOCKS>KEYLESS ACCESS CONTROL MODULE .

   No  : Malfunction occurred in the charger lid external antenna.