DTC B1642 Refrigerant Flow Sensor Circuit Open: Wiring Diagram

Air Conditioning System. See appropriate SYSTEM WIRING DIAGRAM article.

Fig 1: Refrigerant Flow Sensor - Wiring Diagram

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Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK CONNECTOR. Check the connecting condition of connector. Read the DTC using Subaru Select Monitor.	Is B1642 displayed?	Go to step 2 .	Repair the poor connection of the connector.
2 CHECK FLOW SENSOR. Disconnect the flow sensor connector. Short No. 2 and No. 3 of the flow sensor connector (B507). Read the DTC using Subaru Select Monitor.	Is B1641 displayed?	Replace the compressor. Refer to REMOVAL .	Go to step 3 .
3 CHECK HARNESS. Turn the ignition switch to ON. Using the tester, measure the voltage between terminals. Connector & terminal (B507) No. 1 (+) - No. 2 (-):	Is the voltage 4.5 - 5.0 V?	Go to step 4 .	Repair or replace the open circuit of harness.
4 CHECK HARNESS. Disconnect the A/C CM connector. Using a tester, check continuity between terminals. Connector & terminal (B507) No. 3 - (i80) No. 13: (B507) No. 2 - (i181) No. 1: (B507) No. 1 - (i80) No. 16:	Is there continuity?	Replace the A/C CM. Refer to REMOVAL .	Repair or replace the open circuit of harness.