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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Operation
1. On «Start» display, select «Diagnosis».2. On «Vehicle selection» display, input the target vehicle information and select «Confirmed».3. On «Main Menu» display, select «Each System».4. On «Select System» display, select «Tire Pressure Monitor» and then select «Enter».5. On «Sel ...