DTC B14A5: Refrigerant Flow Sensor Circuit Open

DTC detecting condition:

The voltage of the refrigerant flow sensor signal line becomes 4.7 V or more.
Open circuit in refrigerant flow sensor

Trouble symptom:

A/C does not function because refrigerant flow amount cannot be measured.

Wiring diagram:

Air conditioning system. Ref. to WIRING SYSTEM>AIR CONDITIONING SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

CAUTION: Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to AIR CONDITIONER (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION .

CHECK CONNECTOR.
1. Check connecting condition of the A/C Control Module connector, refrigerant flow sensor connector and coupling connector.
2. Read the DTC of [Air Conditioner] using the Subaru Select Monitor. Ref. to AIR CONDITIONER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC B14A5 displayed? (Current malfunction)

Yes : Go to 2.

No : 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.
CHECK REFRIGERANT FLOW SENSOR.
1. Disconnect the refrigerant flow sensor connector.
2. Short No. 2 and No. 3 of the refrigerant flow sensor connector (F161).
3. Read the DTC of [Air Conditioner] using the Subaru Select Monitor. Ref. to AIR CONDITIONER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC B14A6 displayed? (Current malfunction)

Yes : Replace the compressor. Ref. to AIR CON DITIONER>COMPRESSOR .

No : Go to 3.
CHECK HARNESS.
1. Restore the temporary shorted lines made in step 2.
2. Turn the ignition switch to ON.
3. Using a tester, measure the voltage between terminals in refrigerant flow sensor connector.
  Connector and terminal
  
  (F161) No. 1 (+) - (F161) No. 2 (-):
Is the voltage 4.5 - 5.0 V?

Yes : Go to 4.

No : Repair or replace the open circuit of harness.
CHECK HARNESS (OPEN CIRCUIT).
1. Disconnect the A/C Control Module connector.
2. Using a tester, check the continuity between A/C Control Module connector and refrigerant flow sensor connector terminals.
  Connector and terminal
  
  (F161) No. 1 - (i329) No. 12:
  
  (F161) No. 2 - (i329) No. 24:
  
  (F161) No. 3 - (i181) No. 22:
Is there continuity?

Yes : Replace the A/C Control Module. Ref. to AIR CONDITIONER>CONTROL UNIT .

No : Repair or replace the open circuit of harness.