The most common causes are a low refrigerant charge from leaks, a failed AC compressor clutch, or electrical faults such as blown fuses or a bad pressure switch. A professional diagnosis is often needed to confirm the exact cause.
What typically goes wrong
Understanding what can fail in the 2012 Subaru Impreza’s air conditioning system helps you tell a technician what to check. The system relies on refrigerant, a compressor driven by the serpentine belt, electrical controls, and airflow through the cabin. When any of these parts falter, cooling can drop or stop entirely.
Common causes of AC failure in a 2012 Impreza
The following list covers the most frequent reasons an Impreza’s AC stops delivering cold air. Each item represents a plausible culprit you may encounter during inspection or diagnostic testing.
- Low refrigerant charge due to leaks (R-134a): Over time, seals, hoses, or the condenser can develop small leaks, gradually reducing the amount of refrigerant and cooling efficiency.
- AC compressor clutch or compressor failure: The clutch may fail to engage, preventing the compressor from running and circulating refrigerant.
- Electrical issues: Blown fuses or relays, faulty high- or low-pressure switches, or wiring problems can disable the compressor or the climate control system.
- Blocked or damaged condenser or restricted airflow: Debris or a failing cooling fan can prevent heat dissipation, raising head pressure and reducing cooling.
- Clogged expansion device (orifice tube) or degraded evaporator: These can limit refrigerant flow and cooling efficiency, especially if the system was previously overfilling or contaminated.
- Worn belts or belt-driven components: A slipping serpentine belt or a worn pulley reduces compressor operation and system performance.
- Fan not operating properly: If radiator/auxiliary fans don’t run when the AC is on, the system can overheat and the compressor may shut down to protect itself.
These causes range from simple fixes (like replacing a blown fuse) to more involved repairs (like locating a refrigerant leak and recharging the system). A professional mechanic can perform leak testing and confirm refrigerant type and quantity, which is essential for correct repair.
How to diagnose the problem
To narrow down the issue, start with basic checks you can perform safely and then consider diagnostic tests that require specialized tools. Note that handling refrigerant requires appropriate equipment and can be illegal to vent in many places.
- Verify climate-control settings: Ensure the AC is set to cold and the blower is at a sufficient speed. If you have automatic climate control, confirm that the mode isn’t defaulting to a non-cooling setting.
- Check the compressor clutch operation: With the AC on, listen for a distinct click from the compressor area and inspect the center of the pulley—some models show a visible rotation when engaged. If there’s no engagement, the clutch or its electrical drive may be at fault.
- Inspect fuses and relays: Look in the interior fuse box and engine bay for the A/C fuse or relay. Replace a blown fuse with the correct rating and test again. A faulty relay can also prevent the compressor from energizing.
- Assess refrigerant charge (professionally): If the system is cold at the vents but weak, or not cold at all, a technician will measure refrigerant pressures with a manifold gauge set to determine charge level and identify leaks.
- Evaluate condenser and airflow: With the hood open, check that the cooling fans spin when the AC is on and that the condenser has unobstructed airflow. Remove debris if safe to do so.
- Check for leaks or dye marks: A professional can perform a leak test using UV dye or electronic leak detectors and inspect hoses, fittings, and the condenser for signs of refrigerant loss.
- Test the high- and low-pressure readings: Proper pressures vary with ambient temperature, but abnormal readings (very low low-side pressure or excessively high high-side pressure) indicate undercharge, overcharge, or a faulty valve/expansion device.
These diagnostic steps help distinguish between a simple recharge, a mechanical failure, and electrical problems. Given the environmental and safety considerations around refrigerant, many owners opt for a professional service at this stage.
When to seek professional help
Consider contacting a licensed automotive technician if you notice any of the following: persistent inability to cool, unusual noises from the compressor, visible refrigerant leaks, or if gauge readings indicate improper pressures. Professional service is recommended for refrigerant handling, leak repair, and any replacement of the compressor, condenser, or expansion device.
What you can do next
Depending on your findings, you may choose one of these paths. Small issues like a blown fuse or obstructed airflow can be addressed at home, while more complex problems will require a shop visit.
- Replace a blown A/C fuse or relay and re-test the system.
- Remove debris from the condenser area and ensure cooling fans operate reliably.
- Schedule a professional refrigerant recharge and leak repair if a leak is suspected.
- Have the compressor clutch or belt inspected and replaced if signing a fault signal from the clutch or belt drive.
Note: Do not attempt to recharge or vent refrigerant yourself if you are not trained or equipped, as improper handling can be hazardous and illegal in some jurisdictions.
Summary
In a 2012 Subaru Impreza, cooling issues typically stem from a refrigerant leak, a failing compressor or clutch, or electrical problems. Diagnosis starts with basic checks of settings, fuses, and airflow, then moves to pressure testing and leak detection by a professional. Timely service can restore cooling and prevent further damage to the system.
Why did my Subaru AC suddenly stop working?
If your compressor is activating, it likely indicates low refrigerant levels or a blend door that may need replacement. If the compressor does not engage, check the compressor relay. If the relay is functioning properly, the refrigerant level might be too low to allow the compressor to activate.
What are common 2012 Impreza problems?
Common problems with the Subaru Impreza include engine issues, sudden and abrupt acceleration, transmission failure, and air bag problems. The 2008 and 2012 models of the Subaru Impreza should be avoided, but the rest have generally good reliability.
Why is my AC not working in my Subaru Impreza?
The most common reasons a Subaru Impreza AC isn't working are a refrigerant leak, an electrical climate control issue, or a problem with the air conditioning compressor.
How much to fix AC in Subaru Impreza?
On average, the cost for a Subaru Impreza Car AC Repair is $372 with $176 for parts and $196 for labor. Prices may vary depending on your location.