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Diagnosis And Testing - A/C Expansion Valve

WARNING: This page is about a different car, the 2017 Jeep Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
WARNING:

Review the warnings and cautions for this system before performing the procedure. Failure to follow these instructions may result in serious injury or death.

NOTE:

The A/C expansion valve should only be tested after performing the A/C performance test. Refer to DIAGNOSIS AND TESTING .

NOTE:

Liquid CO2 is required to test the A/C expansion valve. This material is available from most welding supply facilities. Liquid CO2 is also available from companies which service and sell fire extinguishers.

When testing the A/C expansion valve, the work area and the vehicle temperature must be 21-27°C (70-85°F). To test the expansion valve:

  1. Connect a charging station or manifold gauge set to the refrigerant system service ports.
  2. Close all doors, windows and vents to the passenger compartment.
  3. Set the A/C heater controls so that the A/C compressor is operating, the temperature control is in the highest temperature position, the mode air door is directing air output to the floor and the blower motor operating is operating at the highest speed.
  4. Start the engine and allow it to idle. After the engine has reached normal operating temperature, allow the passenger compartment to heat up. This will create the need for maximum refrigerant flow into the A/C evaporator.
  5. If the refrigerant charge is sufficient, the discharge (high pressure) gauge should read 827-1655 kPa (120-240 psi). The suction (low pressure) gauge should read 207-345 kPa (30-50 psi). If OK, go to Step 6. If not OK, replace the inoperative A/C expansion valve.
    WARNING:

    Protect the skin and eyes from exposure to liquid CO2 or personal injury can result.

  6. If the suction (low pressure) gauge reads within the specified range, freeze the A/C expansion valve for 30 seconds using liquid CO2 or another suitable super-cold material. Do not spray refrigerant on the A/C expansion valve for this test.  The suction (low pressure) gauge reading should drop by 69 kPa (10 psi). If OK, go to Step 7. If not OK, replace the inoperative A/C expansion valve.
  7. Allow the expansion valve control head to thaw. The suction (low pressure) gauge reading should stabilize at 207-345 kPa (30-50 psi). If not OK, replace the inoperative A/C expansion valve. For removal of the A/C expansion valve. Refer to VALVE, A/C EXPANSION, REMOVAL . For installation of the A/C expansion valve. Refer to VALVE, A/C EXPANSION, INSTALLATION .
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