HVAC System (Auto AC) (Diagnostics): Diagnosis Subaru Outback BR рестайлинг

INSPECTION

Before performing the diagnosis, check the following items which may cause problems in the A/C system.

A/C CONTROL SYSTEM SELF-DIAGNOSIS

DIAGNOSTIC PROCEDURE WHEN SELF DIAGNOSIS USING A/C CONTROL PANEL DOES NOT OPERATE

Note. For diagnostic procedure, refer to NOTHING IS DISPLAYED ON THE SCREEN OR INDICATORS DO NOT ILLUMINATE .

1. Perform diagnosis according to the diagnosis procedure for the corresponding symptom listed in the symptom table.
2. If there are multiple symptoms, perform the diagnosis in the order of symptom number (1 --> 2 -->... --> 13).

SYMPTOM TABLE

TROUBLE SYMPTOM

1. When the AUTO button is pressed with IGN ON, nothing is displayed on the screen or indicators do not illuminate.
2. Self diagnosis using A/C control panel does not operate.

Trouble causes

1. Control module power supply circuit failure
2. A/C control panel power supply failure
3. UART communication failure

Even when the OFF switch is pressed, the blower fan does not turn off, the inlet opening remains in FRESH mode, and the compressor does not turn off.

1. UART communication failure
2. A/C control panel failure
3. Blower motor failure
4. Intake door actuator failure
5. Compressor failure

Even when the DEF switch is pressed, the defroster indicator does not illuminate, the outlet opening is not set to DEF, the compressor does not turn on and the outlet opening is not set to FRESH.

1. UART communication failure
2. A/C control panel failure
3. Mode door actuator failure
4. Compressor failure
5. Intake door actuator failure

Cold air not emitted.

1. Airflow capacity failure
2. Refrigerant pressure failure
3. Air mix actuator (driver's) failure
4. Air mix actuator (passenger's) failure (with left/right independent air conditioner only)
5. Rear vent actuator failure (with rear seat air conditioning only)
6. Intake door actuator failure
7. Evaporator sensor failure (vehicles with automatic air conditioner only)
8. In-vehicle sensor failure (vehicles with automatic air conditioner only)
9. Ambient sensor failure (vehicles with automatic air conditioner only)
10. Sunload sensor failure (vehicles with automatic air conditioner only)

Warm air not emitted.

1. Airflow capacity failure
2. Coolant failure
3. UART communication failure
4. A/C control panel failure
5. Air mix actuator (driver's) failure
6. Air mix actuator (passenger's) failure (with left/right independent air conditioner only)
7. Rear vent actuator failure (with rear seat air conditioning only)
8. Intake door actuator failure
9. Evaporator sensor failure (vehicles with automatic air conditioner only)
10. In-vehicle sensor failure (vehicles with automatic air conditioner only)
11. Ambient sensor failure (vehicles with automatic air conditioner only)
12. Sunload sensor failure (vehicles with automatic air conditioner only)

Compartment temperature is excessively lower than setting temperature.

1. Large airflow capacity
2. Refrigerant pressure failure
3. UART communication failure
4. A/C control panel failure
5. Air mix actuator (driver's) failure
6. Air mix actuator (passenger's) failure (with left/right independent air conditioner only)
7. Rear vent actuator failure (with rear seat air conditioning only)
8. Evaporator sensor failure (vehicles with automatic air conditioner only)
9. In-vehicle sensor failure (vehicles with automatic air conditioner only)
10. Ambient sensor failure (vehicles with automatic air conditioner only)
11. Sunload sensor failure (vehicles with automatic air conditioner only)

Compartment temperature is excessively higher than setting temperature.

1. Large airflow capacity
2. UART communication failure
3. A/C control panel failure
4. Air mix actuator (driver's) failure
5. Air mix actuator (passenger's) failure (with left/right independent air conditioner only)
6. Rear vent actuator failure (with rear seat air conditioning only)
7. Intake door actuator failure
8. Evaporator sensor failure (vehicles with automatic air conditioner only)
9. In-vehicle sensor failure (vehicles with automatic air conditioner only)
10. Ambient sensor failure (vehicles with automatic air conditioner only)
11. Sunload sensor failure (vehicles with automatic air conditioner only)

1. Airflow capacity is insufficient.
2. No air comes out even when the fan switch or fan dial is operated.
3. There is a fan speed at which no air comes out.

1. Airflow capacity failure
2. UART communication failure
3. A/C control panel failure
4. Blower motor failure

Auto A/C

1. The blower rotates even though the blower switch is not turned on.
2. The blower motor continues to rotate at high speed. (Not adjustable.)

1. Airflow capacity failure
2. UART communication failure
3. A/C control panel failure
4. Blower motor failure

Auto A/C

Compressor does not operate even when the A/C switch is turned on and the fan switch is set to LO - HI.

Compressor failure

Even when the FRESH/RECIRC switch is pressed, the inlet opening does not switch to RECIRC --> FRESH or FRESH --> RECIRC.

Intake door actuator failure

Unable to switch blow vents.

1. Auto dual Even when the mode switch is operated, outlet opening does not switch to FACE --> B/L --> FOOT --> F/D.
2. Manual A/C Selected mode does not work even when each mode switch is operated.

Mode door actuator failure

Even when the lighting switch is operated, the illumination does not come on. Even when the illumination control is operated, the illumination does not dim.

Open circuit in illumination circuit

DIAGNOSIS

Defective CAN communication circuit

1. LAN system is abnormal.
2. Communication failure between Subaru Select Monitor and A/C CM

Scheme 40

1. Air Conditioning System. See appropriate SYSTEM WIRING DIAGRAM article.
2. CAN communication system. See appropriate SYSTEM WIRING DIAGRAM article.

DTC DETECTING CONDITION

In-vehicle sensor circuit is shorted.

1. In-vehicle air temperature is falsely recognized as 25°C (77°F), and the compartment temperature is adjusted.
2. DTC "B1601" Short-circuit in in-vehicle sensor was detected.
3. DTC "-21" Short-circuit in in-vehicle sensor was detected.

In-vehicle sensor circuit is open.

1. In-vehicle air temperature is falsely recognized as 25°C (77°F), and the compartment temperature is adjusted.
2. DTC "B1602" Open circuit in in-vehicle sensor was detected.
3. DTC "21" Open circuit in in-vehicle sensor was detected.

Evaporator sensor circuit is shorted.

1. Compressor does not operate. (Variable compressor)
2. Evaporator temperature is falsely recognized as high, and the compartment temperature is adjusted.
3. DTC "B1603" Short-circuit in evaporator sensor was detected.
4. DTC "-23" Short-circuit in evaporator sensor was detected.

Evaporator sensor circuit is open.

1. Compressor does not operate.
2. Evaporator temperature is falsely recognized as low, and the compartment temperature is adjusted.
3. DTC "B1604" Open circuit in evaporator sensor was detected.
4. DTC "23" Open circuit in evaporator sensor was detected.

Refrigerant pressure sensor circuit is open.

1. Compressor does not operate. (Variable compressor)
2. DTC "B1605" Open circuit in refrigerant pressure sensor was detected.
3. DTC "42" Open circuit in refrigerant pressure sensor was detected.

Refrigerant pressure sensor circuit is shorted.

1. Compressor does not operate. (Variable compressor)
2. DTC "B1606" Short-circuit in refrigerant pressure sensor was detected.
3. DTC "-42" Short-circuit in refrigerant pressure sensor was detected.

Sunload sensor circuit is shorted.

1. Operation is performed as no sunload.
2. DTC "B1607" Short-circuit in sunload sensor was detected.
3. DTC "-25" Short-circuit in sunload sensor was detected.
4. DTC "-45" Short-circuit in sunload sensor (auto light control) was detected.

Sunload sensor circuit is open. (Displayed for current malfunction)

Note. When the sunload sensor check is performed indoors or in the shade, it could be diagnosed as having an open circuit. Always check the sunload sensor in direct sunlight.

1. Operation is performed as no sunload.
2. DTC "B1608" Open circuit in sunload sensor was detected.
3. DTC "25" Open circuit in sunload sensor was detected.
4. DTC "45" Open circuit in sunload sensor (auto light control) was detected.

Air mix door actuator potentiometer circuit is open.

1. Temperature cannot be adjusted.
2. Temperature of the driver's side cannot be adjusted for model with left/right independent air conditioner.
3. DTC "B1610" Open circuit in air mix door actuator - potentiometer (driver's) was detected.
4. DTC "26" Open circuit in air mix door actuator - potentiometer (driver's) was detected.

Air mix door actuator potentiometer circuit is shorted.

1. Temperature cannot be adjusted.
2. Temperature of the driver's side cannot be adjusted for model with left/right independent air conditioner.
3. DTC "B1611" Short circuit in air mix door actuator - potentiometer (driver's) was detected.
4. "27" Short circuit in air mix door actuator - potentiometer (driver's) was detected.

1. Driver's air mix door actuator is locked.
2. The potentiometer value of the actuator does not change.

Temperature of the driver's side cannot be adjusted for model with left/right independent air conditioner.

Air mix door actuator potentiometer circuit is open.

1. Temperature of the passenger's side cannot be adjusted for model with left/right independent air conditioner.
2. DTC "B1613" Open circuit in air mix door actuator - potentiometer (passenger's) was detected.
3. DTC "-26" Open circuit in air mix door actuator - potentiometer (passenger's) was detected.

Air mix door actuator potentiometer circuit is shorted.

1. Temperature of the passenger's side cannot be adjusted for model with left/right independent air conditioner.
2. DTC "B1614" Short circuit in air mix door actuator - potentiometer (passenger's) was detected.
3. DTC "-27" Short circuit in air mix door actuator - potentiometer (passenger's) was detected.

Passenger's air mix door actuator is locked.

1. Temperature of the passenger's side cannot be adjusted for model with left/right independent air conditioner.
2. DTC "B1615" Air mix door actuator - lock (passenger's) was detected.
3. DTC "48" Air mix door actuator - lock (passenger's) was detected.

Mode door actuator potentiometer circuit is open.

1. Vent does not change.
2. DTC "B1620" Open circuit in mode door actuator potentiometer was detected.
3. DTC "28" Open circuit in mode door actuator potentiometer was detected.

Mode door actuator potentiometer circuit is shorted.

1. Vent does not change.
2. DTC "B1621" Short circuit in mode door actuator potentiometer was detected.
3. DTC "29" Short circuit in mode door actuator potentiometer was detected.

Mode door actuator locked.

1. DTC "B1622" Mode door actuator lock was detected.
2. DTC "49" Mode door actuator lock was detected.

Rear vent door actuator potentiometer circuit is open.

1. Unable to control the rear vent temperature.
2. DTC "B1630" Open circuit in rear vent door actuator potentiometer was detected.
3. DTC "41" Open circuit in rear vent door actuator potentiometer was detected.

Rear vent door actuator potentiometer circuit is shorted.

1. Unable to control the rear vent temperature.
2. DTC "B1631" Short circuit in rear vent door actuator potentiometer was detected.
3. DTC "-41" Short circuit in rear vent door actuator potentiometer was detected.

Rear vent door actuator is locked.

1. Unable to control the rear vent temperature.
2. DTC "B1632" Rear vent door actuator lock was detected.
3. DTC "52" Rear vent door actuator lock was detected.

1. Ambient sensor to combination meter circuit is shorted or open.
2. Data to be received from the combination meter via CAN communication do not arrive.

1. Ambient temperature is falsely recognized as 15.2°C, and the compartment temperature is adjusted.
2. DTC "22" Faulty ambient sensor, or communication failure was detected.
3. DTC "B1635" OUT SIDE TEMPERATURE SENSOR CIRCUIT ABNORMALITY was detected. Or, DTC "U0002" CAN COMMUNICATION ERROR was detected along with DTC "B1635".

1. The voltage of the sensor signal line decreased to 0.3 V or less.
2. Short-circuit in flow sensor circuit

1. A/C does not function because refrigerant flow amount cannot be measured.
2. DTC "B1641" Short-circuit in refrigerant flow sensor was detected.
3. DTC "-43" Short-circuit in refrigerant flow sensor was detected.

1. The voltage of the sensor signal line increased to 4.7 V or more.
2. Short-circuit in flow sensor circuit

1. A/C does not function because refrigerant flow amount cannot be measured.
2. DTC "B1642" Open circuit in refrigerant flow sensor was detected.
3. DTC "43" Open circuit in refrigerant flow sensor was detected.

Open or short circuit in variable solenoid valve

1. Refrigerant pressure cannot be changed.
2. DTC "B1643" Variable flow change solenoid duty circuit failure was detected.
3. DTC "46" Variable flow change solenoid duty circuit failure was detected.

1. Compressor was operated while refrigerant was low.
2. Compressor was operated while refrigerant pressure was extremely low.
3. Judgment is made only when the delivery mode fuse is installed.

A/C does not operate.

1. Data to be received via CAN communication do not arrive.
2. A/C cooperation control does not operate.

A/C does not operate fully automatically.

DIAGNOSTIC PROCEDURE

1. Data to be received via CAN communication do not arrive.
2. A/C cooperation control does not operate.

A/C does not operate fully automatically.

DIAGNOSTIC PROCEDURE

UART communication failure

1. Unable to operate A/C.
2. DTC "U0028" Heater control panel communication failure was detected.
3. DTC "53" Heater control panel communication failure was detected.