Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

A/C System Performance Test

IMPORTANT: Record the relative humidity and ambient temperature conditions at the time of the test.

System Performance Test:





1. Park the vehicle inside or in the shade. The ambient temperature must be at least 16°C (60°F).
2. Open the windows in order to ventilate the interior.
3. Vent the engine exhaust.
4. Open the hood and install the J 39183-C
5. Record the ambient temperature where the vehicle is parked.
6. Record the relative humidity. Use a psychrometer or consult the local weather bureau.
7. Close all of the doors and the windows. Lower the hood.
8. Set the A/C control assembly to MAX mode with the blower speed set to high and the temperature to full cold. Ensure the vent button LED is not illuminated
9. Open the A/C air outlet deflectors.
10. Place a thermometer in the left center A/C outlet.
11. Place the transaxle in PARK. Start the engine. Let the engine idle.
12. Run the A/C system until the outlet air reaches a stabilized temperature (about 3 minutes).
13. Record the outlet air temperature and the high side and low side pressures.
14. Turn the engine off and compare the readings with the data in the A/C Performance Table. Normally operating A/C systems should not exceed levels shown.
5. If the readings exceed the table limits, refer to High Side vs. Low Side Pressure Table and Gray Area Diagnosis and Service in Cooling Insufficient.
16. If you were sent here from a DTC diagnostic table, clear the DTC upon completion of the test.