Performance Test - Front A/C

A/C Performance Test:

Tools Required:
J 39500 ACR4 Station

Before performing the A/C system performance test, a functional test should be made to ensure that the air delivery system valves are functioning and routing air passing through the evaporator to the outlets. Refer to the "A/C Functional Test" and, if applicable, "Rear A/C Function Test". Functional Test/Check

Performance testing provides a measure of air conditioning system operating efficiency by measuring and comparing ambient air temperature and humidity, pressures at high-pressure and low-pressure sides of the refrigeration system, and the temperature of the air being discharged into passenger compartment.

For poor performance symptoms that affect only the rear heating and air conditioning system, refer to "Rear A/C Insufficient Cooling Diagnosis Chart". Symptom Related Diagnostic Procedures

1. Park vehicle inside or in shade.
2. Open windows to ventilate interior.
3. Vent engine exhaust.
4. Open hood and install high-and low-side pressure gages. Route lines over rear hood seal and tape gages to windshield for viewing by driver.
5. Close hood.
6. Record ambient temperature at vehicle.
7. Record relative humidity. Use psychrometer or consult local weather bureau.

Important
^ Be sure to record relative humidity and ambient temperature conditions at time of test.

8. Close doors and windows.
9. Set mode control at "A/C" with blower control on high and temperature controls on full cold.
10. Open A/C outlets.
11. Place thermometer in right center A/C outlet.
12. Place transaxle in "Park" or "Neutral," start engine, stabilize engine at 2000 rpm and start timer.
13. Run A/C system until outlet air reaches the lowest temperature (about 3 minutes).
14. Record outlet air temperature and high-side and low-side pressures.
15. Turn engine off and compare readings with upper limit data in "A/C Performance Test" table(s). Normally operating A/C system should not exceed levels shown.

Inspect
^ If a malfunction in the refrigerant system is suspected due to abnormal system pressures, check the following:
- Check outer surfaces of radiator and condenser cores to be sure air flow is not blocked by dirt, leaves or other foreign material. Be sure to check between the condenser and radiator as well as the outer surfaces.
- Restrictions in evaporator core or condenser core, or kinks in hoses, tubes, etc.
- Refrigerant leaks.
- Check all air ducts for leaks or restrictions. Low air flow rate may indicate a restricted evaporator core.
- Compressor clutch slippage.
- Improper drive belt tension.
- Plugged accumulator.
- Plugged expansion (orifice) tube. If the problem is not found, continue with diagnostic procedures in "A/C Performance Charts".