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Test Description

WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

This test measures the operating efficiency of the A/C system under the following conditions:

The numbers below refer to the step numbers on the diagnostic table.

  1. 1:  This step determines if the A/C system has at least the minimum refrigerant charge required to operate the system without damage.
  2. 2:  This step measures the performance of the A/C system.
  3. 3:  This step is to allow for vehicle variations as well as high ambient temperatures.
Air Conditioning (A/C) System Performance Test

Step Action Values Yes No
IMPORTANT:
  • The ambient air temperature must be at least 16°C (60°F).
  • 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.
1 
  1. Park the vehicle inside or in the shade.
  2. Open the windows in order to ventilate the interior of the vehicle.
  3. If the A/C system was operating, allow the A/C system to equalize for about 2 minutes.
  4. Turn OFF the ignition.
  5. Install the J 43600  ACR 2000 Air Conditioning Service Center. See Special Tools and Equipment .
  6. Record the ambient air temperature displayed on the J 43600  . See Special Tools and Equipment .
  7. Record the low and high side STATIC pressure readings.
Are both the low side and high side pressures within the specified value?		 Greater than 16°C (60°F) - 345 kPa (50 psi)
Greater than 24°C (75°F) - 483 kPa (70 psi)
Greater than 33°C (90°F) - 690 kPa (100 psi)		 Go to Step 2  Go to Leak Testing 
2 
    IMPORTANT: Record the relative humidity and the ambient air temperature at the time of the test.
  1. Close the vehicle doors and windows.
  2. Open the drivers door window 12.7-15.2 cm (5-6 in).
  3. Select the following HVAC control settings:
    • A/C setting
    • Recirculation mode
    • Maximum blower speed
    • Panel mode
    • Coldest temperature setting
    • All panel outlets are Open
  4. Install the temperature probes of the J 43600  in the left and right center panel air outlets. See Special Tools and Equipment .
  5. Apply the parking brake.
  6. Place the transaxle in PARK
  7. Start the engine.
  8. Operate the A/C system for 5 minutes.
  9. Inspect A/C components for the following conditions:
    • Abnormal frost areas
    • Unusual noises
    10. IMPORTANT: Press the RESET button, before using the print function of the J 43600  . See Special Tools and Equipment .
  10. Print the following information:
    • The panel outlet air temperature
    • The low-side pressure
    • The high-side pressure
  11. Compare the low and high side pressures and the panel output temperature to the table below.
Does all the data recorded fall within the specified ranges of the table below?		 - Go to Step 8  Go to Step 3 
3  If the pressures and temperatures recorded do not fall within the specified ranges:
  1. Continue to operate the A/C system for an additional 5 minutes.
  2. RESET the J 43600  and record the pressures and temperature again. See Special Tools and Equipment .
  3. Compare the low and high side pressures and the panel output temperature to the table below.

Does all the data recorded fall within the specified ranges of the table below?		 - Go to Step 8  Go to Step 4 
4 Do the high and low side pressures fall within the specified ranges, but the panel outlet temperature do not? - Go to Air Conditioning (A/C) Diagnostics - Pressure Zone A  Go to Step 5 
5 Is the low side pressure greater than the specified range, but the high side pressure within or less than the specified range? - Go to Air Conditioning (A/C) Diagnostics - Pressure Zone B  Go to Step 6 
6 Are the low and high side pressures both greater than the specified ranges? - Go to Air Conditioning (A/C) Diagnostics - Pressure Zone C  Go to Step 7 
7 Is the high side pressure greater than the specified range, but the low side pressure is within or less than the specified range? - Go to Air Conditioning (A/C) Diagnostics - Pressure Zone D  Go to Step 8 
8 Operate the system in order to verify the test results.
Did you find the same results?		 - System OK Go to Symptoms - HVAC Systems - Manual or Symptoms - HVAC Systems - Automatic
Fig 1: A/C System Pressure - Zone Classification
GM668773Courtesy of GENERAL MOTORS CORP.
A/C Performance Table

Ambient Air Temperature Relative Humidity Service Port Pressure Maximum Left Center Discharge Air Temperature
Low Side High Side
13-18°C (55-65°F) 0-100% 197-225 kPa (29-33 psi) 1100-1230 kPa (160-178 psi) 9°C (48°F)
19-23°C (66-75°F) Below 40% 191-228 kPa (28-33 psi) 1060-1230 kPa (154-178 psi) 10°C (50°F)
Above 40% 202-246 kPa (29-36 psi) 1100-1370 kPa (160-199 psi) 12°C (54°F)
24-29°C (76-85°F) Below 35% 194-230 kPa (28-33 psi) 1130-1220 kPa (164-177 psi) 11°C (52°F)
35-60% 198-246 kPa (29-36 psi) 1090-1320 kPa (158-191 psi) 12°C (54°F)
Above 60% 236-311 kPa (34-45 psi) 1140-1580 kPa (165-229 psi) 15°C (59°F)
30-35°C (86-95°F) Below 30% 208-256 kPa (30-37 psi) 1230-1370 kPa (178-199 psi) 14°C (57°F)
30-50% 215-284 kPa (31-41 psi) 1180-1540 kPa (171-223 psi) 16°C (61°F)
Above 50% 236-311 kPa (34-45 psi) 1290-1750 kPa (187-254 psi) 18°C (64°F)
36-40°C (96-105°F) Below 20% 235-298 kPa (34-43 psi) 1340-1600 kPa (194-232 psi) 17°C (63°F)
20-40% 246-315 kPa (36-46 psi) 1340-1700 kPa (194-247 psi) 18°C (64°F)
Above 40% 260-348 kPa (38-51 psi) 1410-1940 kPa (204-281 psi) 21°C (70°F)
41-46°C (106-115°F) Below 20% 266-339 kPa (39-49 psi) 1550-1820 kPa (225-264 psi) 21°C (70°F)
Above 20% 280-369 kPa (41-54 psi) 1530-2000 kPa (222-290 psi) 23°C (73°F)
47-49°C (116-120°F) Below 30% 304-378 kPa (44-55 psi) 1870-2020 kPa (271-293 psi) 24°C (75°F)
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