DTC B1647: Side Satellite Sensor Bus LH Lost Communication

Diagnosis start condition:

When the ignition voltage is 10 - 16 V.

DTC detecting condition:

Open or short circuit in harness of Side impact sensor LH (center pillar)
Side impact sensor LH (center pillar) is faulty.
Open or short circuit in harness of Side impact sensor LH (rear wheel house)
Side impact sensor LH (rear wheel house) is faulty.
Open or short circuit in harness of Side impact sensor LH (front door)
Side impact sensor LH (front door) is faulty.
Airbag control module is faulty.

Failure detection pattern:

"Primary" (high-priority diagnosis)

Warning light/indicator light:

Airbag warning light◦

Wiring diagram:

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

Is DTC B1627 or B1628 displayed? (Current code)

Yes: Perform the diagnosis for the displayed DTC B1627 or B1628. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)>DTC B1627 SIDE AIRBAG SENSOR LH LOST COMMUNICATION . AIRBAG (DIAGNOSTICS)>DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)>DTC B1628 SIDE AIRBAG SENSOR LH INITIALIZATION ERROR .

No: GO TO 2.
CHECK DTC .
Read the DTC of [Airbag] using the Subaru Select Monitor. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

Is DTC B1637 or B1638 displayed? (Current code)

Yes: Perform the diagnosis for the displayed DTC B1637 or B1638. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)>DTC B1637 CURTAIN AIRBAG SENSOR LH LOST COMMUNICATION . AIRBAG (DIAGNOSTICS)>DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)>DTC B1638 CURTAIN AIRBAG SENSOR LH INITIALIZATION ERROR .

No: GO TO 3.
CHECK DTC .
Read the DTC of [Airbag] using the Subaru Select Monitor. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

Is DTC B1697 or B1698 displayed? (Current code)

Yes: Perform the diagnosis for the displayed DTC B1697 or B1698. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)>DTC B1697 LOST COMMUNICATION WITH DOOR SENSOR LH . AIRBAG (DIAGNOSTICS)>DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)>DTC B1698 DOOR SENSOR LH INITIALIZATION INCOMPLETE .

No: GO TO 4.
CHECK POOR CONTACT OF CONNECTORS .
Check for poor contact of the connectors between the airbag control module and Side impact sensor LH (front door).

Is there poor contact?

Yes: Replace the airbag rear harness and the door harness.

No: GO TO 5.
CHECK AIRBAG REAR HARNESS (BETWEEN AIRBAG CONTROL MODULE AND Side impact sensor LH (center pillar)) (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. Disconnect the connector (AB94) from seat belt pretensioner LH.
3. Disconnect the connector (AB96) from lap seat belt pretensioner LH.
4. Disconnect the connector (AB100) from rear seat belt pretensioner LH.
5. Disconnect the connector (AB88) from side airbag module LH.
6. Disconnect the connector (AB92) from curtain airbag module LH.
7. Disconnect the connectors (AB41, AB42, AB43) from airbag control module.
8. Connect the connector (1BF) in the test harness BF to the connectors (AB41, AB42, AB43).
9. Disconnect the connector (AB56) from Side impact sensor LH (center pillar).
10. Connect the connector (1BH) in the test harness BH to the connector (AB56).
11. Measure the resistance between connector (6BF) in the test harness BF and connector (2BH) in the test harness BH.
  Connector & terminal
  
  (6BF) No. 1 - (2BH) No. 1:
  
  (6BF) No. 6 - (2BH) No. 2:
Is the resistance less than 10 Ω?

Yes: GO TO 6.

No: Replace the airbag rear harness along with body harness.
CHECK AIRBAG REAR HARNESS (BETWEEN AIRBAG CONTROL MODULE AND Side impact sensor LH (center pillar)) (SHORTED TO GROUND AND SHORTED BETWEEN LINES) .
Measure the resistance between connector (6BF) in the test harness BF and chassis ground, and the resistance between connector (6BF) terminals in the test harness BF.

Connector & terminal

(6BF) No. 1 - Chassis ground:

(6BF) No. 6 - Chassis ground:

(6BF) No. 1 - (6BF) No. 6:

Is the resistance 1 MΩ or more?

Yes: GO TO 7.

No: Replace the airbag rear harness along with body harness.
CHECK AIRBAG REAR HARNESS (BETWEEN AIRBAG CONTROL MODULE AND Side impact sensor LH (rear wheel house)) (OPEN CIRCUIT) .
1. Disconnect the connector (AB58) from Side impact sensor LH (rear wheel house).
2. Connect the connector (1BH) in the test harness BH to the connector (AB58).
3. Measure the resistance between connector (6BF) in the test harness BF and connector (2BH) in the test harness BH.
  Connector & terminal
  
  (6BF) No. 7 - (2BH) No. 1:
  
  (6BF) No. 2 - (2BH) No. 2:
Is the resistance less than 10 Ω?

Yes: GO TO 8.

No: Replace the airbag rear harness along with body harness.
CHECK AIRBAG REAR HARNESS (BETWEEN AIRBAG CONTROL MODULE AND Side impact sensor LH (rear wheel house)) (SHORTED TO GROUND AND SHORTED BETWEEN LINES) .
Measure the resistance between connector (6BF) in the test harness BF and chassis ground, and the resistance between connector (6BF) terminals in the test harness BF.

Connector & terminal

(6BF) No. 7 - Chassis ground:

(6BF) No. 2 - Chassis ground:

(6BF) No. 7 - (6BF) No. 2:

Is the resistance 1 MΩ or more?

Yes: GO TO 9.

No: Replace the airbag rear harness along with body harness.
CHECK AIRBAG REAR HARNESS AND DOOR HARNESS (BETWEEN AIRBAG CONTROL MODULE AND Side impact sensor LH (front door)) (OPEN CIRCUIT) .
1. Disconnect the connector (AB62) from Side impact sensor LH (front door).
2. Connect the connector (1H) in the test harness H to the connector (AB62).
3. Measure the resistance between connector (6BF) in the test harness BF and connector (3H) in the test harness H.
  Connector & terminal
  
  (6BF) No. 8 - (3H) No. 6:
  
  (6BF) No. 3 - (3H) No. 5:
Is the resistance less than 10 Ω?

Yes: GO TO 10.

No: Check the door harness, and if any fault is found, replace the harness. If there is no fault, replace the airbag rear harness together with body harness.
CHECK AIRBAG REAR HARNESS AND DOOR HARNESS (BETWEEN AIRBAG CONTROL MODULE AND Side impact sensor LH (front door)) (SHORTED TO GROUND AND SHORTED BETWEEN LINES) .
Measure the resistance between connector (6BF) in the test harness BF and chassis ground, and the resistance between connector (6BF) terminals in the test harness BF.

Connector & terminal

(6BF) No. 8 - Chassis ground:

(6BF) No. 3 - Chassis ground:

(6BF) No. 8 - (6BF) No. 3:

Is the resistance 1 MΩ or more?

Yes: GO TO 11.

No: Check the door harness, and if any fault is found, replace the harness. If there is no fault, replace the airbag rear harness together with body harness.
CHECK AIRBAG CONTROL MODULE .
1. Disconnect all test harnesses.
2. Connect all connectors.
3. Using the Subaru Select Monitor, perform the clear memory of [Airbag]. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY .
4. Execute the inspection mode. Ref. to AIRBAG (DIAGNOSTICS)>INSPECTION MODE .
5. Read the DTC of [Airbag] using the Subaru Select Monitor. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC B1647 displayed? (Current code)

Yes: GO TO 12.

No: Finish the diagnosis.
REPLACE Side impact sensor LH (center pillar) AND CHECK AIRBAG CONTROL MODULE AFTER REPLACEMENT .
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. Replace Side impact sensor LH (center pillar). Ref. to AIRBAG SYSTEM>IMPACT SENSOR>REMOVAL .
3. Connect all connectors.
4. Using the Subaru Select Monitor, perform the clear memory of [Airbag]. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY .
5. Execute the inspection mode. Ref. to AIRBAG (DIAGNOSTICS)>INSPECTION MODE .
6. Read the DTC of [Airbag] using the Subaru Select Monitor. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC B1647 displayed? (Current code)

Yes: GO TO 13.

No: Finish the diagnosis.
REPLACE Side impact sensor LH (rear wheel house) AND CHECK AIRBAG CONTROL MODULE AFTER REPLACEMENT .
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. Replace Side impact sensor LH (rear wheel house). Ref. to AIRBAG SYSTEM>IMPACT SENSOR>REMOVAL .
3. Connect all connectors.
4. Using the Subaru Select Monitor, perform the clear memory of [Airbag]. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY .
5. Execute the inspection mode. Ref. to AIRBAG (DIAGNOSTICS)>INSPECTION MODE .
6. Read the DTC of [Airbag] using the Subaru Select Monitor. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC B1647 displayed? (Current code)

Yes: GO TO 14.

No: Finish the diagnosis.
REPLACE Side impact sensor LH (front door) AND CHECK AIRBAG CONTROL MODULE AFTER REPLACEMENT .
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. Replace Side impact sensor LH (front door). Ref. to AIRBAG SYSTEM>IMPACT SENSOR>REMOVAL .
3. Connect all connectors.
4. Using the Subaru Select Monitor, perform the clear memory of [Airbag]. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY .
5. Execute the inspection mode. Ref. to AIRBAG (DIAGNOSTICS)>INSPECTION MODE .
6. Read the DTC of [Airbag] using the Subaru Select Monitor. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC B1647 displayed? (Current code)

Yes: Replace the airbag control module. Ref. to AIRBAG SYSTEM>AIRBAG CONTROL MODULE>REMOVAL .

No: Finish the diagnosis.