DTC 4B Side Airbag LH Failure: Wiring Diagram

WARNING: This page is about a different car, the 2012 Subaru Forester. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Side Airbag LH Failure - Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE CHART

Step	Check	Yes	No
1 CHECK POOR CONTACT OF CONNECTORS. Check for poor contact of the connectors between the airbag control module, side airbag module LH and the side airbag sensor LH.	Is there poor contact?	Replace the airbag rear harness along with body harness.	Go to step 2 .
2 CHECK SIDE AIRBAG MODULE. Turn the ignition switch to OFF, disconnect the battery ground cable, and wait for 60 seconds or more. Disconnect the connector (AB19) from the side airbag module (LH), and connect the connector (1AJ) in test harness AJ to the connector (AB19). Connect the airbag resistor to the test harness AJ connector (3AJ). Connect the battery ground terminal and turn the ignition switch to ON.	Does the airbag warning light illuminate for 6 seconds and go off?	Replace the side airbag module (LH). < Ref. to REMOVAL , Side Airbag Module. >	Go to step 3 .
3 CHECK AIRBAG REAR HARNESS (SIDE AIRBAG MODULE HARNESS LH). Turn the ignition switch to OFF, disconnect the battery ground cable, and wait for 60 seconds or more. Disconnect the connector (AB21) from seat belt pretensioner (LH). Disconnect the connector (AB31) from curtain airbag module (LH). Disconnect the airbag resistor from test harness AJ. Disconnect the connectors (AB6, AB17, AB18) from airbag control module. Connect the connector (1 AG) in the test harness AG to the connectors (AB6, AB17, AB18). Measure the resistance between connector (5AG) terminals in test harness AG. Connector & terminal (5AG) No. 1 - (5AG) No. 3:	Is the resistance 1 MΩ or more?	Go to step 4 .	Replace the airbag rear harness along with body harness.
4 CHECK AIRBAG CONTROL MODULE. Connect all connectors. Clear the memory. Perform the Inspection Mode. Read the DTC.	Is the same DTC displayed?	Replace the airbag control module. < Ref. to AIRBAG CONTROL MODULE . >	Go to step 5 .
5 CHECK FOR ANY OTHER DTC ON DISPLAY.	Is any other DTC displayed?	Check DTC using "List of Diagnostic Trouble Code (DTC)". < Ref. to LIST OF DIAGNOSTIC TROUBLE CODE (DTC) . >	Finish the diagnosis.