Performance Test - Service Stall

IMPORTANT:
^ 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).

^ L81 Engine:
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.

^ L61 Engine:
a. Using Scan tool, perform HVAC PERFORMANCE test using an engine speed of 2,000 rpm. This test will command the A/C relay On, turn the cooling fans on medium speed and hold the engine speed to 2,000 rpm. A/C System Performance Test

NOTE: If the ECT is too high or the A/C high side pressure is too high, the engine control module (ECM-L81) or powertrain control module (PCM-L61) will override 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.