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 (IMPREZA MODEL)>TELEMATICS SYSTEM>WIRING DIAGRAM . Ref. to WIRING SYSTEM (CROSSTREK MODEL (EXCEPT FOR HEV))>TELEMATICS SYSTEM>WIRING DIAGRAM . Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>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 malfunction)

   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 again.

   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 telematics antenna connector.
   3. Disconnect the DCM connector.
   4. Measure the resistance between telematics antenna connector and DCM connector.

      Connector and terminal 

      (AN52) No. 1 - (AN12) 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 and terminal 

   (AN52) 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 and terminal 

      (AN52) 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. Check the telematics antenna. Ref. to ENTERTAINMENT & MONITORING>ANTENNA .

   Is the check result OK?

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

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