Common Hyundai Compressor Problems and How to Fix Them

Fix a three common Hyundai AC compressor problems using this Hyundai service bulletin

Hyundai has issued a service bulletin #17-HA-002 to address 3 common Hyundai compressor problems where the AC does not get cold enough. The service bulletin includes information about the torque limiter slip clutch, how to diagnose it, and the compressor control valve.

Follow this bulletin if you have no cooling or the the high and/or low sides show abnormal system pressure on the manifold gauge (normal pressure should be > 130-psi at idle on the high side with AC set to MAX)

Diagnose Hyundai compressor problems by checking the pressure and the pulley operation

1. Start the engine, set the blower speed to level 2, and select MAX AC with the coldest temp setting.
2. Check the AC pressure. High side pressure must be above 130 PSI
3. If the high side pressure is below spec, inspect the limiter of the disc & hub assembly while rotating the engine.

The compressor pulley contains a built-in torque limiter slip clutch to prevent AC drive belt disengagement in the event of a compressor seize. If the compressor seizes, the clutch will shear off the engagement points, allowing the pulley to continue to spin while no longer applying rotational force to the compressor input shaft.

How to check for a sheared torque limiter slip clutch

During normal operation, the center bolt at the front of the pulley will rotate at the same speed as the pulley. If the pulley spins but the center bolt does not, the torque limiter slip clutch has sheared due to internal binding, and the compressor must be replaced.

If the center bolt is rotating, proceed with the diagnosis

A bad external control valve ECV is a common Hyundai compressor problem. Here’s how to check it with a resistance test

The external control valve is mounted to the rear of the Hyundai compressor and it regulates how much suction and compression the compressor outputs. If the ECV fails, you’ll have little or no cooling.

Using the diagnosis kit  in Hyundai part 00305

ACKIT TOOL , connect a multimeter  to leads

External control valve

from the ECV and check resistance. The kit contains extension harnesses needed for testing. Normal ECV resistance should be 10.1 ~ 11.1Ω when the ambient temperature is 77°F. However, resistance may vary due to higher underhood temperatures. The acceptable range is (8 Ω ≤ ECV Resistance ≤ 14 Ω).

If the resistance is outside of the acceptable range, replace the ECV.

Conduct the AC pressure test

Using the test kit according to the instructions, start the engine and set the blower to speed 2. The selector should be set to MAX, and the engine should be at idle speed.

Turn the kit switch to the ON position and check the AC pressures. Low side should show20 – 40psi, High side 130 – 190psi

Do NOT conduct this test for more than 30 seconds, or you could experience evaporator core freeze-up or expansion valve freeze-up.

If the pressure is normal, as shown above, check all the wiring to the AC heater control head. Repair any damaged wiring/connection.

If the pressures are out of specification, check the following:

• Check the radiator cooling fans for proper operation
• Evacuate the system and install the correct refrigerant charge.
• Check the AC lines, expansion valve, evaporator and condenser fins for blockage.
• Check the ECV valve for corroded, damaged or bent pins.
• Replace the ECV if not other faults are found.

©, 2021 Rick Muscoplat