Subaru Legacy BN/BS (2015-2019) Service Manual: Dtc b14b3 seat heater thermistor circuit open (passenger)

Subaru Legacy BN/BS (2015-2019) Service Manual / Hvac system (diagnostics) / Diagnostic procedure with diagnostic trouble code (dtc) / Dtc b14b3 seat heater thermistor circuit open (passenger)

DTC DETECTING CONDITION:

Open circuit in seat heater thermistor.

TROUBLE SYMPTOM:

Seat heater RH does not function.

WIRING DIAGRAM:

NOTE:

For the coupling connector, refer to “WIRING SYSTEM”.

Seat Heater System Seat Heater System > WIRING DIAGRAM

STEP	CHECK	YES	NO
1.CHECK CONNECTOR. 1) Check connecting condition of the A/C CM connector, seat heater relay connector, seat connector and coupling connector. 2) Read the DTC using Subaru Select Monitor. Read Diagnostic Trouble Code (DTC)	Is B14B3 displayed-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B14B3 SEAT HEATER THERMISTOR CIRCUIT OPEN (PASSENGER)	Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again. NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
2.CHECK SEAT HEATER RH. 1) Disconnect the seat connector (R334) or (R44). 2) For vehicle with power seat, short No. 2 and No. 6 of seat connector (R334). For vehicle without power seat, short No. 2 and No. 4 of seat connector (R44). 3) Read the DTC using Subaru Select Monitor. Read Diagnostic Trouble Code (DTC)	Is B14B4 displayed-	Replace the seat heater module and wire set - front seat cushion. Seat Heater System > REMOVAL	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B14B3 SEAT HEATER THERMISTOR CIRCUIT OPEN (PASSENGER)
3.CHECK HARNESS. 1) Restore the temporary shorted lines made in step 2. 2) Turn the ignition switch to ON. 3) Turn the seat heater switch RH to ON. 4) Using the tester, measure the voltage between terminals. Connector & terminal With power seat (R334) No. 2 (+) — (R334) No. 6 (−): Without power seat (R44) No. 2 (+) — (R44) No. 4 (−):	Is the voltage 4.5 — 5.0 V-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B14B3 SEAT HEATER THERMISTOR CIRCUIT OPEN (PASSENGER)	Repair or replace the open circuit of harness.
4.CHECK HARNESS (OPEN CIRCUIT). 1) Disconnect the A/C CM connector. 2) Using a tester, check continuity between terminals. Connector & terminal With power seat (R334) No. 2 — (i80) No. 14: (R334) No. 6 — (i181) No. 18: Without power seat (R44) No. 2 — (i80) No. 14: (R44) No. 4 — (i181) No. 18:	Is there continuity-	Replace the A/C CM. Control Unit > REMOVAL	Repair or replace the open circuit of harness.

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