Compartment Temperature Is Excessively Lower Than Setting Temperature

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

Trouble symptom:

Compartment temperature is excessively lower than setting temperature.

Trouble causes:

Large airflow capacity
Refrigerant pressure failure
CAN communication failure
A/C control panel failure
Air mix actuator failure
Evaporator sensor failure
In-vehicle sensor failure
Ambient sensor failure
Sunload sensor failure
Heat pump system failure
UART communication failure

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 CONDITIONER (DIAGNOSTICS) (HEV)>GENERAL DESCRIPTION>CAUTION .

CHECK AIRFLOW CAPACITY .
Check the airflow capacity. Ref. to AIR CONDITIONER (DIAGNOSTICS) (HEV)>DIAGNOSTICS WITH PHENOMENON>INSPECTION>AIR GOES OUT OF CONTROL, (BLOWER MOTOR ROTATES AT HIGH SPEED) .

Is the check result OK?

Yes: Go to 2.

No: Perform repair according to inspection procedure.
CHECK AMOUNT OF REFRIGERANT PRESSURE .
Check the refrigerant pressure. Ref. to AIR CONDITIONER (HEV)>REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET .

Is the check result OK?

Yes: Go to 3.

No: Perform repair according to refrigerant pressure inspection.
CHECK A/C CONTROL PANEL .
1. Turn to READY ON.
2. Set the temperature control dial to MAX COOL.
3. Using the Subaru Select Monitor, check the following items in the [Data Monitor] of [Air Conditioner]. Ref. to AIR CONDITIONER (DIAGNOSTICS) (HEV)>DATA MONITOR .
- Heater Control Panel Setting Value (Driver's)
Does [Heater Control Panel Setting Value (Driver's)] indicate "59"*1?

(*1: For the 72°F center specification. 17.5 for the 25°C center specification.)

Yes: Go to 4.

No: Replace the A/C control panel. Ref. to AIR CONDITIONER (HEV)>CONTROL PANEL .
CHECK A/C CONTROL PANEL .
1. Set the temperature control dial to MAX HOT.
2. Using the Subaru Select Monitor, check the following items in the [Data Monitor] of [Air Conditioner]. Ref. to AIR CONDITIONER (DIAGNOSTICS) (HEV)>DATA MONITOR .
- Heater Control Panel Setting Value (Driver's)
Does [Heater Control Panel Setting Value (Driver's)] indicate "86"*2?

(*2: For the 72°F center specification. 32.5 for the 25°C center specification.)

Yes: Go to 5.

No: Replace the A/C control panel. Ref. to AIR CONDITIONER (HEV)>CONTROL PANEL .
CHECK DTC .
1. Turn the temperature control dial at MAX COOL and leave for 16 seconds or more.
2. Read the following DTCs using Subaru Select Monitor. Ref. to AIR CONDITIONER (DIAGNOSTICS) (HEV)>DIAGNOSTIC TROUBLE CODE (DTC) . Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
- Air Conditioner
- P-HEV Hybrid Powertrain Control
Are any DTCs displayed? (Current malfunction)

Yes: Perform the diagnosis for the displayed DTCs. Ref. to AIR CONDITIONER (DIAGNOSTICS) (HEV)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST . Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

No: Go to 6.
CHECK DTC .
1. Turn the temperature control dial at MAX HOT and leave for 16 seconds or more.
2. Read the following DTCs using Subaru Select Monitor. Ref. to AIR CONDITIONER (DIAGNOSTICS) (HEV)>DIAGNOSTIC TROUBLE CODE (DTC) . Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
- Air Conditioner
- P-HEV Hybrid Powertrain Control
Are any DTCs displayed? (Current malfunction)

Yes: Perform the diagnosis for the displayed DTCs. Ref. to AIR CONDITIONER (DIAGNOSTICS) (HEV)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST . Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

No: Go to 7.
CHECK EVAPORATOR SENSOR UNIT .
Perform the inspection of evaporator sensor unit. Ref. to AIR CONDITIONER (HEV)>EVAPORATOR SENSOR .

Is the check result OK?

Yes: Go to 8.

No: Replace the evaporator sensor. Ref. to AIR CONDITIONER (HEV)>EVAPORATOR .
CHECK IN-VEHICLE SENSOR UNIT .
Check in-vehicle sensor. Ref. to AIR CONDITIONER (HEV)>IN-VEHICLE SENSOR (AUTO A/C MODEL) .

Is the check result OK?

Yes: Go to 9.

No: Replace the in-vehicle sensor. Ref. to AIR CONDITIONER (HEV)>IN-VEHICLE SENSOR (AUTO A/C MODEL) .
CHECK AMBIENT SENSOR UNIT .
Check the ambient sensor. Ref. to AIR CONDITIONER (HEV)> AMBIENT SENSOR .

Is the check result OK?

Yes: Go to 10.

No: Replace the ambient sensor. Ref. to AIR CONDITIONER (HEV)>AMBIENT SENSOR .
CHECK SUNLOAD SENSOR UNIT .
Check the sunload sensor unit. Ref. to AIR CONDITIONER (HEV)>SUNLOAD SENSOR (AUTO A/C MODEL) .

Is the check result OK?

Yes: Go to 11.

No: Replace the sunload sensor. Ref. to AIR CONDITIONER (HEV)>SUNLOAD SENSOR (AUTO A/C MODEL) .
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 and terminal
  
  (i365) No. 40 (+) - Chassis ground (-):
Is the voltage 11 - 14 V or more?

Yes: Go to 12.

No: Repair or replace the open, short circuit of the harness.
CHECK HEAT PUMP CONTROL MODULE .
Replace the heat pump control module with a properly functioning part. Ref. to AIR CONDITIONER (HEV)>CONTROL UNIT .

Is the faulty phenomenon reproduced?

Yes: Go to 13.

No: Malfunction occurred in the heat pump control module.
PERFORM UNIT INSPECTION OF HEAT PUMP SYSTEM PARTS .
Perform unit inspection of the following parts.
- Low pressure solenoid valve Ref. to AIR CONDITIONER (HEV)>SOLENOID VALVE>INSPECTION .
- High pressure solenoid valve Ref. to AIR CONDITIONER (HEV)>SOLENOID VALVE>INSPECTION .
- Heating expansion valve Ref. to AIR CONDITIONER (HEV)>EXPANSION VALVE>INSPECTION .
- Cooling expansion valve Ref. to AIR CONDITIONER (HEV)>EXPANSION VALVE>INSPECTION .
- Interior condenser exit temperature sensor Ref. to AIR CONDITIONER (HEV)>PIPE TEMPERATURE SENSOR>INSPECTION .
- Exterior condenser exit temperature sensor Ref. to AIR CONDITIONER (HEV)>PIPE TEMPERATURE SENSOR>INSPECTION .
- Discharge temperature sensor Ref. to AIR CONDITIONER (HEV)>PIPE TEMPERATURE SENSOR>INSPECTION .
- Evaporator exit temperature sensor Ref. to AIR CONDITIONER (HEV)>PIPE TEMPERATURE SENSOR>INSPECTION .
Is the check result OK?

Yes: 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.

No: Repair it according to unit inspection of parts.