Diagnostic Procedure for Subaru Select Monitor Communication: Inspection

Trouble symptom:

Cannot communicate with [Airbag].

DTC detecting condition:

Defective harness connector
Power supply circuit malfunction
Defective CAN communication circuit
Defective Subaru Select Monitor

Wiring diagram:

Airbag system Ref. to WIRING SYSTEM>AIRBAG SYSTEM>WIRING DIAGRAM .
CAN communication system Ref. to WIRING SYSTEM>CAN COMMUNICATION SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

CAUTION: Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to AIRBAG (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION .

CHECK CENTRAL GATEWAY CONTROL MODULE AND SUBARU SELECT MONITOR COMMUNICATION .
Using Subaru Select Monitor, check that it can normally communicate with the [Central Gateway].

Is the check result OK?

Yes: GO TO 5.

No: GO TO 2.
CHECK SUBARU SELECT MONITOR .
Connect the Subaru Select Monitor to another vehicle, and check for the communication.

Is the check result OK?

Yes: GO TO 3.

No: Repair or replace the Subaru Select Monitor.
CHECK DATA LINK CONNECTOR .
1. Turn the ignition switch to ON.
2. Using the tester, measure the voltage between data link connector and chassis ground.
  Connector & terminal
  
  (i221) No. 16 (+) - Chassis ground (-):
  
  (i221) No. 8 (+) - Chassis ground (-):
Is the voltage 10 V or more?

Yes: Check the central gateway control module. Ref. to CENTRAL GATEWAY (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

No: GO TO 4.
CHECK FUSE .
1. Turn the ignition switch to OFF.
2. Remove a fuse in the data link connector and visually check the fuse. Ref. to WIRING SYSTEM>CAN COMMUNICATION SYSTEM>WIRING DIAGRAM .
Is the check result OK?

Yes: Repair the harness between the battery and the data link connector.

No: Replace the fuse. If the fuse is blown out again, check the power supply circuit.
CHECK AIRBAG CONTROL MODULE CONNECTOR .
1. Turn the ignition switch to OFF, and wait for 60 seconds or more after disconnecting the ground terminal from the battery sensor. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
2. Confirm that the connectors of airbag control module (AB41, AB42, AB43) are securely connected.
Is the check result OK?

Yes: GO TO 6.

No: Connect the connector of the airbag control module.
CHECK FUSE .
Remove fuse No. 20 from the fuse & relay box, and fuse No. 10 and fuse No. 21 from the main fuse box, and perform visual inspection. Ref. to WIRING SYSTEM>AIRBAG SYSTEM>WIRING DIAGRAM .

Is the check result OK?

Yes: GO TO 7.

No: Replace the fuse. If the fuse is blown out again, check the power supply circuit.
CHECK AIRBAG CONTROL MODULE POWER SUPPLY CIRCUIT .
1. Disconnect the connectors (AB41, AB42, AB43) from airbag control module.
2. Connect the connector (1BF) in the test harness BF to the connectors (AB41, AB42, AB43).
3. Turn the ignition switch to ON.
4. Measure the voltage between connector (2BF) in the test harness BF and chassis ground.
  Connector & terminal
  
  (2BF) No. 4 (+) - Chassis ground (-):
  
  (2BF) No. 5 (+) - Chassis ground (-):
Is the voltage 10 V or more?

Yes: GO TO 8.

No: Repair the harness between the airbag control module and the battery. Or replace the airbag main harness along with the bulkhead harness.
CHECK BETWEEN AIRBAG CONTROL MODULE AND CHASSIS GROUND (OPEN CIRCUIT) .
1. Turn the ignition switch to OFF, and wait for 60 seconds or more after disconnecting the ground terminal from the battery sensor. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
2. Measure the resistance between connector (2BF) in the test harness BF and chassis ground.
  Connector & terminal
  
  (2BF) No. 1 - Chassis ground:
  
  (2BF) No. 2 - Chassis ground:
Is the resistance less than 10 Ω?

Yes: GO TO 9.

No: Repair the harness between the airbag control module and the chassis ground. Or replace the airbag main harness along with the bulkhead harness.
CHECK POOR CONTACT OF CONNECTOR .
Check for poor contact of the control module power supply, the ground line and the data link connector.

Is there poor contact?

Yes: Repair the connector. (Replace the harness without repairing the airbag system connector.)

No: Replace the airbag control module. Ref. to AIRBAG SYSTEM>AIRBAG CONTROL MODULE>REMOVAL .