Subaru Legacy BN/BS (2015-2019) Service Manual: Dtc b1870 short in front seat cushion airbag rh

Subaru Legacy BN/BS (2015-2019) Service Manual / Airbag system (diagnostics) / Diagnostic chart with trouble code / Dtc b1870 short in front seat cushion airbag rh

DIAGNOSIS START CONDITION:

Ignition voltage is 10 V to 16 V.

DTC DETECTING CONDITION:

Shorted between +/− lines (shorted between rear harness lines, shorted between front seat cushion airbag RH lines, shorted between airbag CM internal lines)

CAUTION:

Before performing diagnosis, refer to “CAUTION” in “General Description”. General Description > CAUTION

WIRING DIAGRAM:

Airbag system Airbag System > WIRING DIAGRAM

STEP	CHECK	YES	NO
1.CHECK POOR CONTACT OF CONNECTORS. Check for poor contact of the connectors between the airbag control module and the seat cushion airbag module RH.	Is there poor contact-	Replace the airbag rear harness along with body harness.	Diagnostic Chart with Trouble Code > DTC B1870 SHORT IN FRONT SEAT CUSHION AIRBAG RH
2.CHECK SEAT CUSHION AIRBAG MODULE. 1) Turn the ignition switch to OFF, disconnect the battery ground cable, and wait for 60 seconds or more. 2) Disconnect the connector (AB22) from the seat cushion airbag module RH, and connect the connector (1D) in the test harness D to connector (AB22). 3) Connect the airbag resistor to connector (3D) in the test harness D. 4) 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 seat cushion airbag module RH. Seat Cushion Airbag Module	Diagnostic Chart with Trouble Code > DTC B1870 SHORT IN FRONT SEAT CUSHION AIRBAG RH
3.CHECK AIRBAG REAR HARNESS (SEAT CUSHION AIRBAG MODULE HARNESS RH) (SHORTED BETWEEN LINES). 1) Turn the ignition switch to OFF, disconnect the battery ground cable, and wait for 60 seconds or more. 2) Disconnect the connector (AB26) from seat belt pretensioner RH. 3) Disconnect the connector (AB24) of side airbag module RH. 4) Disconnect the connector (AB33) from curtain airbag module RH. 5) Disconnect the airbag resistor from test harness D. 6) Disconnect the connectors (AB6, AB17, AB18) from airbag control module. 7) Connect the connector (1AD) in test harness AD AV to the connectors (AB6, AB17, AB18). 8) Connect the connector (2AD) in test harness AD AV and the connector (1AG) in test harness AG. 9) Measure the resistance between connector (3D) terminals in test harness D. Connector & terminal (3D) No. 3 — (3D) No. 4:	Is the resistance 1 M- or more-	Diagnostic Chart with Trouble Code > DTC B1870 SHORT IN FRONT SEAT CUSHION AIRBAG RH	Replace the airbag rear harness along with body harness.
4.CHECK AIRBAG CONTROL MODULE. 1) Connect all connectors. 2) Clear the memory. Clear Memory Mode 3) Perform the Inspection Mode. Inspection Mode 4) Read the DTC. (Current malfunction) Read Diagnostic Trouble Code (DTC)	Is DTC B1870 displayed-	Replace the airbag control module. Airbag Control Module	Diagnostic Chart with Trouble Code > DTC B1870 SHORT IN FRONT SEAT CUSHION AIRBAG RH
5.CHECK FOR ANY OTHER DTC ON DISPLAY. Read the DTC. (Current malfunction) Read Diagnostic Trouble Code (DTC)	Is any other DTC displayed-	Check DTC using “List of Diagnostic Trouble Code (DTC)”. List of Diagnostic Trouble Code (DTC)	Finish the diagnosis.

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Other materials:

Caution
• Prior to starting work, pay special attention to the following:1. Always wear work clothes, a work cap, and protective shoes. Additionally, wear a helmet, protective goggles, etc. if necessary.2. Protect the vehicle using a seat cover, fender cover, etc.3. Prepare the service tools, clean cl ...