DTC B2A0E: Mute Line Circuit

Diagnosis start condition:

When ignition switch is ON.

DTC detecting condition:

Any of the following conditions occurs continuously for five seconds or more after the ignition switch is turned to ON when DCM does not mute the audio or navigation system.

Current in the mute line is less than 1 mA. (Improper line connection, etc.)
Current exceeds 50 mA. (Short-circuited line, etc.)

Trouble symptom:

The mute function of audio or navigation system does not operate.
RED LED illuminates.

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 .

Wiring diagram:

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

Courtesy of SUBARU OF AMERICA, INC.

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

Is DTC B2A0E 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.
CHECK HARNESS (OPEN CIRCUIT) .
1. Turn the ignition switch to OFF.
2. Disconnect the cockpit control module connector.
3. Disconnect the DCM connector.
4. Measure the resistance between the cockpit control module connector and DCM connector.
  Connector & terminal
  
  (i105) No. 19 - (i101) No. 38:
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) .
Measure the resistance between DCM connector and chassis ground.

Connector & terminal

(i105) No. 19 - 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. Measure the voltage between DCM connector and chassis ground.
  Connector & terminal
  
  (i105) No. 19 (+) - 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.