Subaru Legacy BN/BS (2015-2019) Service Manual: Dtc b1431 in-vehicle (post evaporator) temperature sensor circuit short-circuit

Subaru Legacy BN/BS (2015-2019) Service Manual / Hvac system (diagnostics) / Diagnostic procedure with diagnostic trouble code (dtc) / Dtc b1431 in-vehicle (post evaporator) temperature sensor circuit short-circuit

DTC DETECTING CONDITION:

In-vehicle sensor circuit is shorted.

TROUBLE SYMPTOM:

In-vehicle air temperature is falsely recognized as 25°C (77°F), and the compartment temperature is adjusted.

WIRING DIAGRAM:

Air conditioning system Air Conditioning System > WIRING DIAGRAM

STEP	CHECK	YES	NO
1.CHECK CONNECTOR. 1) Check connecting condition of the A/C CM connector and in-vehicle sensor connector. 2) Read the DTC using Subaru Select Monitor. Read Diagnostic Trouble Code (DTC)	Is B1431 displayed-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B1431 IN-VEHICLE (POST EVAPORATOR) TEMPERATURE SENSOR CIRCUIT SHORT-CIRCUIT	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 IN-VEHICLE SENSOR. 1) Disconnect the in-vehicle sensor. In-Vehicle Sensor (Auto A/C Model) > REMOVAL 2) Read the DTC of the A/C CM using the Subaru Select Monitor. Read Diagnostic Trouble Code (DTC)	Is B1430 displayed-	Replace the in-vehicle sensor. In-Vehicle Sensor (Auto A/C Model) > REMOVAL	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B1431 IN-VEHICLE (POST EVAPORATOR) TEMPERATURE SENSOR CIRCUIT SHORT-CIRCUIT
3.CHECK HARNESS. 1) Turn the ignition switch to ON. 2) Using the tester, measure the voltage between terminals. Connector & terminal (i173) No. 1 (+) — No. 2 (−):	Is the voltage 4.5 — 5.0 V-	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.	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B1431 IN-VEHICLE (POST EVAPORATOR) TEMPERATURE SENSOR CIRCUIT SHORT-CIRCUIT
4.CHECK HARNESS (SHORTED BETWEEN LINES). 1) Disconnect the connector from A/C CM. 2) Using a tester, check continuity between terminals. Connector & terminal (i173) No. 1 — No. 2:	Is there continuity-	Repair or replace the short circuit of the harness.	Replace the A/C CM. Control Unit > REMOVAL

Dtc b1432 ambient temperature sensor circuit open (air-conditioner)

DTC DETECTING CONDITION:• Ambient sensor to combination meter circuit is open.• Data to be received from the combination meter via CAN communication do not arrive.TROUBLE SYMPTOM:• D ...

General description

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Other materials:

Inspection
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