GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 39183-C R-134a Manifold Gauge Set
    • J 6742-03 Thermometer Dial

    Important: Perform the A/C system performance test only under the following conditions:

       • The vehicle is not exposed to direct sunlight.
       • The ambient temperature is within 15-35°C (59-95°F).

  1. Turn the ignition switch to LOCK.
  2. Apply the parking brake.
  3. Connect the J 39183-C manifold gauge set HIGH side (RED) and LOW side (BLUE) hoses to their respective service ports on the vehicle.
  4. Set the air mode to VENT.
  5. Set the fresh/recirc to RECIRC.
  6. Set the temperature control to full COLD.
  7. Start the engine and let it warm up to the normal operating temperature. Let the engine run at normal idle speed.
  8. Set the blower speed to HIGH.
  9. Press the A/C switch to ON.
  10. Place the J 6742-03 thermometer dial probe through the IP center outlet.
  11. Keep all of the doors, the windows and the hood open.
  12. Monitor the gauge set and record the refrigerant pressures when they stabilize.
  13. Monitor the thermometer and record the center outlet air temperature when it stabilizes.
  14. Turn the blower speed to OFF.
  15. Turn the ignition switch to LOCK.
  16. Remove the thermometer.
  17. Disconnect the manifold gauge set.

Compare the recorded HIGH and LOW side refrigerant system pressures and the outlet air temperature with the tables below. If the recorded values are not within specifications, refer to TXV Air Conditioning (A/C) System Diagnosis .


Object Number: 345538  Size: MF
(1)Normal High Side Pressure Range
(2)Normal Low Side Pressure Range
(3)System Pressure vs. Ambient Temperature Graph
(4)Normal Center Air Outlet Temperature Range
(5)Center Air Outlet Temperature vs. Ambient Temperature Graph