Performance Test - Service Stall
Service Stall Test ProcedureIMPORTANT:
^ If ambient air temperature is lower than 0°C (32°F), A/C compressor will not be enabled.
^ This test must be performed in a service stall environment that protects the vehicle from wind that could cause incorrect pressure/temperature readings.
1. Open hood and leave open during entire test.
2. Install a manifold gauge set to high and low side service ports.
3. Start engine.
4. Turn A/C Off A/C button indicator light Off.
5. Depress re-circulation button so that indicator light is lit.
6. Install thermometer into right center outlet.
7. Set mode knob to I/P outlet position - full counter-clockwise.
8. Set temperature knob to full cold position - full counter-clockwise.
9. Set blower to third speed - M2.
10. Open both front doors and windows to stabilize interior air temperature with outside ambient temperature.
11. Start engine and allow engine coolant temperature (ECT) to reach 86°C (188°F).
a. Turn A/C On, using the console button.
b. Using Scan tool, command FAN CONTROL 2 On, which will run both cooling fans at medium speed.
c. Using accelerator pedal, increase engine speed to 2,000 rpm and hold.
NOTE: If the ECT is too high or the A/C high side pressure is too high, the engine control module (ECM-L81) will over-ride the fan control request and the cooling fans will be commanded on high.
12. Record A/C system pressures and outlet temperature every minute for five minutes.
13. Exit out of the Scan tool test and return engine to idle.
14. Release Tech 2 control of engine cooling fans.
15. Compare recorded values to system performance charts then continue down diagnostic flow chart.
Normal System Performance
Normal System Performance Service Stall - L81:
IMPORTANT:
^ To ensure accurate pressure and temperature readings make sure the vehicle is properly set up to run the performance test. (Refer to vehicle set up.) All test parameters must be followed to obtain accurate readings. Testing and Inspection
^ Use a refrigerant identifier to verify refrigerant purity. Non-condensable gases or refrigerant substitutes will affect system pressure/temperature readings.
Normal System Performance High Humidity
Normal System Performance Service Stall High Humidity - L81:
^ High humidity conditions affect system performance by increased heat load on system. This extra heat load will increase discharge pressure and outlet temperature. High humidity is defined as a relative humidity higher than 70 percent at 21°C (70°F), 60 percent at 27°C (80°F), 50 percent at 32°C (90°F). and 40 percent at 38°C (100°F).
^ This chart illustrates the effect high humidity has on the Saturn air conditioning system. Use this chart to determine normal system performance under high humidity conditions.