DTC B2A01: LTE1 Antenna Circuit

Diagnosis start condition: 

When ignition switch is ON.

DTC detecting condition: 

Any of the followings continues for 5 seconds or more.

• LTE1 impedance is more than 1 MΩ. (Detached antenna, etc.)
• LTE1 impedance is less than 1 kΩ. (Short-circuited antenna, etc.)

Trouble symptom: 

• Telematics function cannot be used.
• RED LED illuminates.

Wiring diagram: 

Telematics Ref. to WIRING SYSTEM>TELEMATICS SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC  .
   1. Turn the ignition switch to ON.
   2. Read the DTC of [Telematics] using the Subaru Select Monitor. Ref. to TELEMATICS SYSTEM (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B2A01 displayed? (Current code)

   Yes:  Go to  2.

   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.

   NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
2. CHECK HARNESS (OPEN CIRCUIT)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the antenna connector.
   3. Disconnect the DCM connector.
   4. Using a tester, measure the resistance between DCM connector and telematics antenna connector.

      Connector & terminal 

      (An46) No. 1 - (An71) No. 1:

   Is the resistance less than 1 Ω?

   Yes:  Go to  3.

   No:  Repair or replace the open circuit of harness.

3. CHECK HARNESS (GROUND SHORT CIRCUIT)  .

   Measure the resistance between DCM connector and chassis ground.

   Connector & terminal 

   (An46) No. 1 - Chassis ground:

   Is the resistance 1 MΩ or more?

   Yes:  Go to  4.

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

4. CHECK HARNESS (SHORT CIRCUIT TO POWER SUPPLY)  .
   1. Turn the ignition switch to ON.
   2. Measure the voltage between DCM connector and chassis ground.

      Connector & terminal 

      (An46) No. 1 (+) - Chassis ground (-):

   Is the voltage less than 1 V?

   Yes:  Go to  5.

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

5. CHECK ANTENNA  .
   1. Turn the ignition switch to OFF.
   2. Using a tester, measure the internal resistance of telematics antenna.

   Courtesy of SUBARU OF AMERICA, INC.

   Terminals 

   No. 1 - No. A:

   Is the resistance between 9 and 11 kΩ?

   Yes:  Replace the DCM. Ref. to ENTERTAINMENT & MONITORING>DATA COMMUNICATION MODULE .

   No:  Replace the telematics antenna. Ref. to ENTERTAINMENT & MONITORING>ANTENNA .