DTC B1450: Low-Pressure Solenoid Valve Circuit/Open

WARNING: This page is about a different variant/trim than selected.

DTC detecting condition:

When Low pressure solenoid valve circuit is faulty.

Trouble symptom:

Compressor does not operate.

Wiring diagram:

Air conditioning system Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>AIR CONDITIONING SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

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

CHECK CONNECTOR .
1. Check connecting condition of the A/C control panel connector, heat pump Control Module connector and Low pressure solenoid valve connector.
2. Turn the ignition switch to ON.
3. Read the DTC of [Air Conditioner] using the Subaru Select Monitor. Ref. to AIR CONDITIONERS (DIAGNOSTICS) (HEV)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC B1450 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 HEAT PUMP CONTROL MODULE .
1. Turn the ignition switch to OFF.
2. Disconnect the heat pump Control Module connector.
3. Using a tester, measure the voltage between the heat pump Control Module connector and chassis ground.
  Connector & terminal
  
  (i365) No. 23 (+) - Chassis ground (-):
Is the voltage 11 - 14 V?

Yes : Go to 3.

No : Go to 5.
CHECK Low pressure solenoid valve .
1. Disconnect the Low pressure solenoid valve connector. Ref. to AIR CONDITIONER (HEV)>SOLENOID VALVE .
2. Using the tester, measure the resistance between Low pressure solenoid valve terminals.
  Connector & terminal
  
  (B657) No. 1 - (B657) No. 2:
Is the resistance 12.2 - 13.7 Ω?

Yes : Go to 4.

No : Replace Low pressure solenoid valve. Ref. to AIR CONDITIONER (HEV)>SOLENOID VALVE .
CHECK HARNESS (SHORTED BETWEEN LINES) .
Using a tester, measure the resistance between Low pressure solenoid valve connector terminals.

Connector & terminal

(B657) No. 1 - (B657) No. 2:

Is the resistance 10 kΩ or more?

Yes : Replace the heat pump Control Module. Ref. to AIR CONDITIONER (HEV)>CONTROL UNIT .

No : Repair or replace the short circuit of the harness.
CHECK Low pressure solenoid valve POWER SUPPLY CIRCUIT .
1. Disconnect the Low pressure solenoid valve connector. Ref. to AIR CONDITIONER (HEV)>SOLENOID VALVE .
2. Using a tester, measure the voltage between Low pressure solenoid valve connector terminals.
  Connector & terminal
  
  (B657) No. 2 (+) - Chassis ground (-):
Is the voltage 11 - 14 V?

Yes : Go to 6.

No : Repair or replace the open circuit of harness.
CHECK HARNESS (OPEN CIRCUIT) .
Using a tester, measure the resistance between the Low pressure solenoid valve connector and heat pump Control Module connector.

Connector & terminal

(B657) No. 1 - (i365) No. 23:

Is the resistance less than 1 Ω?

Yes : Go to 7.

No : Repair or replace the open circuit of harness.
CHECK HARNESS (GROUND SHORT CIRCUIT) .
Using a tester, measure the resistance between Low pressure solenoid valve connector and chassis ground.

Connector & terminal

(B657) No. 1 - Chassis ground:

Is the resistance 10 kΩ or more?

Yes : Replace Low pressure solenoid valve. Ref. to AIR CONDITIONER (HEV)>SOLENOID VALVE .

No : Repair or replace the short circuit of the harness.