DTC B1618: Front Sub Sensor LH Initialization Error

Diagnosis start condition:

When the ignition voltage is 10 - 16 V.

DTC detecting condition:

Open or short circuit in harness of front sensor bus LH
Front sub sensor LH is faulty.
Airbag control module is faulty.

Wiring diagram:

Airbag system Ref. to WIRING SYSTEM (IMPREZA MODEL)>AIRBAG SYSTEM>WIRING DIAGRAM . Ref. to WIRING SYSTEM (CROSSTREK MODEL (EXCEPT FOR HEV))>AIRBAG SYSTEM>WIRING DIAGRAM . Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>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 POOR CONTACT OF CONNECTORS .
Check for poor contact of the connectors (AB6, AB13) between the airbag control module and the front sub sensor LH.

Is there poor contact?

Yes: Replace the airbag main harness along with body harness.

No: Go to 2.
CHECK AIRBAG MAIN HARNESS (FRONT SENSOR BUS RH) .
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>REPAIR CONTENTS>NOTE>BATTERY .
  NOTE: For the hybrid model, turn the ignition switch to OFF, and wait for 60 seconds or more after disconnecting the negative terminal from the battery.
2. Remove the instrument panel lower cover and column cover, and disconnect the connectors (AB7) and (AB2).
3. Remove the console front panel and disconnect the connector (AB9).
4. Disconnect the connector (AB66) from the driver's knee airbag module.
5. Disconnect the connectors (AB6, AB17, AB18) from airbag control module.
6. Connect the connector (1AG) in the test harness AG to the connectors (AB6, AB17, AB18).
7. Disconnect the connector (AB13) from the front sub sensor LH, and then connect the connector (1H) in the test harness H to connector (AB13).
8. Measure the resistance between connector (4AG) in the test harness AG and connector (3H) in the test harness H.
  Connector & terminal
  
  (4AG) No. 7 - (3H) No. 5:
  
  (4AG) No. 9 - (3H) No. 6:
Is the resistance less than 10 Ω?

Yes: Go to 3.

No: Replace the airbag main harness along with body harness.
CHECK AIRBAG MAIN HARNESS (FRONT SENSOR BUS LH) .
Measure the resistance between connector (4AG) in the test harness AG and chassis ground, and the resistance between connector (4AG) terminals in the test harness AG.

Connector & terminal

(4AG) No. 7 - Chassis ground:

(4AG) No. 9 - Chassis ground:

(4AG) No. 7 - (4AG) No. 9:

Is the resistance 1 MΩ or more?

Yes: Go to 4.

No: Replace the airbag main harness along with body harness.
CHECK AIRBAG CONTROL MODULE .
1. Connect all connectors.
2. Install the ground terminal to the battery sensor and turn the ignition switch to ON. Ref. to REPAIR CONTENTS>REPAIR CONTENTS>NOTE>BATTERY .
  NOTE: For the hybrid model, connect the battery negative terminal and turn the ignition switch to ON.
3. Using the Subaru Select Monitor, perform the clear memory of [Airbag]. Ref. to COMMON (DIAG)>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 B1618 displayed? (Current malfunction)

Yes: Replace the front sub sensor RH. Ref. to AIRBAG SYSTEM>FRONT SUB SENSOR>REMOVAL . Replace the airbag control module if not operating normally even after replacing the sensor. Ref. to AIRBAG SYSTEM>AIRBAG CONTROL MODULE> REMOVAL .

No: Go to 5.
CHECK FOR ANY OTHER DTC ON DISPLAY .
Read the DTC of [Airbag] using the Subaru Select Monitor. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

Is any other DTC displayed? (Current malfunction)

Yes: Perform the diagnosis for other displayed DTCs. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

No: Finish the diagnosis.