The Role of Modern Equipment in Proper Servicing of Electric A/C Compressors in Vehicles. MS112 Test Bench

Summer is a season that has been growing increasingly hotter in Eastern Europe in recent years. This once again underscores the importance of the equipment that keeps vehicle owners and passengers comfortable—the air‑conditioning system. For service stations, this in turn highlights the need for equipment that enables precise diagnostics and high‑quality repairs. Moreover, modern vehicles are becoming ever more electrified, which is driving the rising popularity of electric compressors in air‑conditioning systems. Diagnosing and repairing these compressors call for a specialized approach and dedicated equipment.

Why an A/C System Matters

A modern vehicle air conditioner does much more than just cool the cabin. It also:

• Maintains a comfortable temperature year-round
• Dehumidifies the air, preventing window fogging
• Improves driver and passenger comfort during long trips
• Enhances driving safety by helping the driver stay focused

This becomes especially critical in electric and hybrid vehicles because:

• The A/C system plays a vital role in regulating the temperature of the high-voltage battery. Overheating or overcooling the battery can drastically reduce its lifespan.
• In hybrid vehicles, the A/C must be able to run independently of the internal combustion engine—even when it’s off.

Given the high-tech nature of these systems, quality maintenance and repairs are more important than ever.

Types of Compressors

Compressor type is determined by vehicle design, engine type, and energy efficiency needs. While we won’t go into the technical inner workings, A/C compressors generally fall into two main categories:

1. Mechanical Compressors – Driven by a belt connected to the internal combustion engine. Their performance depends on engine RPM, which reduces energy efficiency.
2. Electric Compressors – Operate independently of the engine and are powered by the vehicle’s high-voltage battery.

Advantages of electric compressors include:

• Stable operation at any engine speed—or even when the engine is off
• Reduced load on the powertrain
• Compact size and quieter performance

Electric compressors are commonly used in:

• Electric vehicles (EVs)
• Hybrid vehicles (HEVs, PHEVs)
• Start-stop system vehicles
• And any other applications where comfort must be ensured regardless of engine activity

Construction and Features of Electric Compressors

An electric compressor is a sophisticated electromechanical device that typically includes:

• An inverter
• An electric motor
• Control electronics
• Sensors and controllers

Electric compressors differ significantly from belt-driven models—especially when it comes to servicing. One key distinction is that the electric motor is housed inside the compressor body, in direct contact with refrigerant and oil. This requires the use of special dielectric oil and demands high levels of system hermeticity.

Another important feature: most electric compressors don’t have an oil drain plug. That means oil levels in the system can’t be adjusted through the compressor itself. For this reason, it’s absolutely essential to thoroughly flush the A/C system before installing a new compressor. This ensures no residual oil remains and prevents overfilling. Any components that can’t be flushed, such as the receiver-drier, must be replaced.

Efficiency is also a major concern, since the compressor draws power directly from the battery. Some compressor malfunctions can severely impact an EV’s range by rapidly depleting the battery.

Proper Service for Electric A/C Compressors

There’s another important point to consider: electric compressors operate at voltages between 200–400V. That means only certified technicians trained to work with high-voltage systems should handle them. Specialized equipment is also a must. That’s where the MS112 test bench comes in—a dedicated solution for diagnosing electric vehicle A/C compressors.

Key Advantages of the MS112:

The MS112 automates the diagnostic process as much as possible, offering two main testing modes:

1. Full Test – Runs a complete diagnostic cycle, thoroughly checking the compressor’s electrical systems and overall performance
2. Express Test – A quick check to filter out obviously faulty compressors by simply running the motor without nitrogen injection

The test bench uses compressed nitrogen as the working gas, supplied from an external tank. The system operates at a pressure of 7–8 bar, consuming about 100 standard liters per test. Nitrogen is not recovered after use—it is safely vented into the atmosphere. The nitrogen inlet uses an SAE 1/4” connector.

The entire process is controlled via a touchscreen interface. Test results can be saved and printed. The bench includes a built-in database of compressor types used in different vehicles, with free lifetime software updates. Peripheral devices can be connected via USB Type-C.

Compact and Portable:
The MS112 measures just 74×60×55 cm and weighs 40 kg. To operate it, all you need is a single-phase 230V electrical outlet and a nitrogen source.

Given the steadily growing number of electric and hybrid vehicles in the fleets of Ukraine and Eastern Europe, it is safe to say that the MS112 is a unique piece of equipment that enables the launch of a new line of business without losing a single day in the upcoming season.