DTC B2A09: I-Call Button Circuit

Diagnosis start condition: 

When ignition switch is ON.

DTC detecting condition: 

The following conditions occur for at least 50 ms.

• i-button impedance is more than 10 kΩ.
• i-button is stuck for at least 60 seconds.

Trouble symptom: 

• i-Call function cannot be used.
• RED LED illuminates.

Wiring diagram: 

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

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC. 

   Read the DTC. Refer to TELEMATICS SYSTEM (DIAGNOSTICS)>DIAGNOSTIC CODE(S) DISPLAY .

   Is DTC B2A09 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. 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 button connector.
   3. Disconnect the DCM connector.
   4. Measure the resistance between telematics button connector and DCM connector.

      Connector & terminal 

      (i270) No. 4 - (AD4) No. 3:

      (AD4) No. 1 - Chassis ground:

   Is the resistance 1 Ω or less?

   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 

   (i270) No. 4 - 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 THE CONNECTOR (SHORT CIRCUIT TO POWER SUPPLY). 

   Measure the voltage between DCM connector and chassis ground.

   Connector & terminal 

   (i270) No. 4 (+) - Chassis ground (-):

   (AD4) 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 THE I-BUTTON. 

   Measure the resistance of the i-button unit.

   Terminals 

   No. 3 - No. 1:

   Is the resistance 1 Ω or less when i-button is ON, and 1.6 (±5%) kΩ or more when i-button is OFF?

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

   No:  Replace the telematics button. Refer to ENTERTAINMENT & MONITORING>SWITCHES AND HARNESS .