A/C Performance Test
WARNING: This page is about a different car, the 2002 GMC Safari and 2002 Chevrolet Astro. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
General Motors uses the ACR 2000 Air Conditioning Service Center (J-43600) for most operations described in this article.
NOTE:
The ambient air temperature must be at least 60°F (16°C). Do not induce additional air flow across the front of the vehicle during the test. If you were sent here from a DTC diagnostic table, clear the DTC upon completion of this test.
NOTE:
Specifications are as follows: 50 psi (345 kPa) at 60° (16°C) or higher, 70 psi (483 kPa) at 75°F (24°C) or higher and 100 psi (690 kPa) at 90°F (33°C) or higher.
- Park the vehicle inside or in the shade. Open the windows in order to ventilate the interior of the vehicle. If the A/C system was operating, allow the A/C system to equalize for about 2 minutes. Turn the ignition Off. Install the ACR 2000 Air Conditioning Service Center. Record the ambient air temperature displayed on the ACR 2000 Air Conditioning Service Center. Record the low and high side static pressure readings. Are both the low side and high side pressures within the specified value? If so, go to next step. If not, see LEAK TESTING in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING.
- Close the vehicle doors and windows. Open the drivers door window 5-6 inches (12.7-15.2 cm). Select the following HVAC control settings:
- The A/C is on.
- Maximum blower speed.
- VENT mode.
- Coldest temperature setting.
- A/C outlets are open.
Install the temperature probes of the ACR 2000 Air Conditioning Service Center in the left and right center A/C air outlets. Apply the parking brake. Place the transmission in Park. Start the engine and operate the A/C system for 5 minutes. Inspect A/C components for abnormal frost areas and unusual noises.
Print the following information: The outlet air temperatures and the low-side and high-side pressures. Compare the low and high side pressures and the output temperatures to the A/C performance table. See Fig 1. Does all the data recorded fall within the specified ranges of the A/C performance table? If so, go to step 4. If not, go to next step.
- If the pressures and temperatures recorded do not fall within the specified ranges, continue to operate the A/C system for an additional 5 minutes. Reset the ACR 2000 Air Conditioning Service Center and record the pressures and temperatures again. Compare the low and high side pressures and the output temperature to the A/C performance table. Does all the data recorded fall within the specified ranges of the A/C performance table? If so, go to step 8. If not, go to next step.
- Do the high and low side pressures fall within the specified ranges, but the outlet temperatures do not? If so, See A/C PRESSURE ZONE "A" DIAGNOSIS under SYSTEM TESTS. If not, go to next step.
- Is the low side pressure greater than the specified range, but the high side pressure within or less than the specified range? If so, see A/C PRESSURE ZONE "B" DIAGNOSIS under SYSTEM TESTS. If not, go to next step.
- Are the low and high side pressures both greater than the specified ranges? If so, see A/C PRESSURE ZONE "C" DIAGNOSIS under SYSTEM TESTS. If not, go to next step.
- Is the high side pressure greater than the specified range, but the low side pressure is within or less than the specified range? If so, see A/C PRESSURE ZONE "D" DIAGNOSIS under SYSTEM TESTS. If not, go to next step.
- Operate the system in order to verify the test results. Did you find the same results? If so, system is okay. If not, see SYMPTOM DIAGNOSIS under TROUBLE SHOOTING.
NOTE:
Record the relative humidity and the ambient air temperature at the time of the test.
NOTE:
Press the reset button, before using the print function of the ACR 2000 Air Conditioning Service Center.