DTC B2A04: Mic Circuit

Diagnosis start condition:

When ACC is ON.

DTC detecting condition:

Any of the followings continues for 1 second or more.

MIC impedance is more than 10 kΩ. (Detached MIC, etc.)
MIC impedance is less than 10 Ω. (Short-circuited MIC, etc.)

Trouble symptom:

Call function cannot be used.
RED LED illuminates.

Wiring diagram:

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

Courtesy of SUBARU OF AMERICA, INC.

CAUTION:

After the DCM is replaced, registrations of CommCheck and immobilizer system are required. Ref. to ENTERTAINMENT & MONITORING>TELEMATICS SYSTEM>OPERATION>REGISTRATION (COMM CHECK)
Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to TELEMATICS SYSTEM (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION

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 B2A04 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 again.

NOTE:
In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
CHECK HARNESS (OPEN CIRCUIT) .
1. Turn the ignition switch to OFF.
2. Disconnect the microphone connector.
3. Disconnect the DCM connector.
4. Using a tester, measure the resistance between the DCM connector and microphone connector.
  Connector & terminal
  
  (i106) No. 8 - (Rf11) No. 5:
  
  (i106) No. 14 - (Rf11) No. 16:
  
  (i106) No. 6 - (Rf11) No. 7:
Is the resistance 1 Ω or less?

Yes : Go to 3.

No : Repair or replace the open circuit of harness.
CHECK HARNESS (GROUND SHORT CIRCUIT) .
Using a tester, measure the resistance between DCM connector and chassis ground.

Connector & terminal

(i106) No. 8 - Chassis ground:

(i106) No. 14 - Chassis ground:

(i106) No. 6 - Chassis ground:

Is the resistance 1 MΩ or more?

Yes : Go to 4.

No : Repair or replace the short circuit of the harness.
CHECK THE CONNECTOR (SHORT CIRCUIT TO POWER SUPPLY) .
1. Turn the ignition switch to ON.
2. Using a tester, measure the voltage between DCM connector and chassis ground.
  Connector & terminal
  
  (i106) No. 8 (+) - Chassis ground (-):
  
  (i106) No. 14 (+) - Chassis ground (-):
  
  (i106) No. 6 (+) - Chassis ground (-):
Is the voltage less than 1 V?

Yes : Go to 5.

No : Repair or replace the short circuit of the harness.
CHECK MICROPHONE UNIT .
1. Turn the ignition switch to OFF.
2. Connect all the disconnected connectors.
3. Confirm the microphone voice input.
Is the check result OK?

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

No : Replace the microphone. Ref. to ENTERTAINMENT & MONITORING>MICROPHONE