DTC B2A0D: Airbag Signal Performance

Diagnosis start condition: 

When ignition switch is ON.

DTC detecting condition: 

Either the regular signal or collision detection signal cannot be detected from the airbag Control Module for at least 30 seconds.

Trouble symptom: 

• ACN function does not operate.
• RED LED illuminates.

Wiring diagram: 

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

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC  .

   Read the DTC of [Telematics] using the Subaru Select Monitor. Ref. to TELEMATICS SYSTEM (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B2A0D 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 DTC  .

   Read the DTC of [Airbag] using the Subaru Select Monitor. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Are any DTCs displayed? (Current code)

   Yes:  Perform the diagnosis for the displayed DTCs of airbag. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

   No:  Go to  3.

3. CHECK HARNESS (OPEN CIRCUIT)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the airbag Control Module connector.
   3. Disconnect the DCM connector.
   4. Measure the resistance between airbag Control Module connector and DCM connector.
      CAUTION: To measure the voltage and resistance of airbag system component, be sure to use the specified test harness. Ref. to AIRBAG (DIAGNOSTICS)>GENERAL DESCRIPTION .

      Connector & terminal 

      (i105) No. 18 - (2BF) No. 7:

   Is the resistance 1 Ω or less?

   Yes:  Go to  4.

   No:  Repair or replace the open circuit of harness.

4. CHECK HARNESS (GROUND SHORT CIRCUIT)  .

   Measure the resistance between DCM connector and chassis ground.

   Connector & terminal 

   (i105) No. 18 - Chassis ground:

   Is the resistance 1 MΩ or more?

   Yes:  Go to  5.

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

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

      Connector & terminal 

      (i105) No. 18 (+) - Chassis ground (-):

   Is the voltage less than 1 V?

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

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