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Test Description

WARNING: This page is about a different car, the 2007 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.

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 .
  6. Record the ambient air temperature displayed on the J 43600  . See Special Tools .
  7. Record the low and high side STATIC pressure readings.
Are both the low side and high side pressures within the specified value?		 More than 16°C (60°F) - 345 kPa (50 psi)
More than 24°C (75°F) - 483 kPa (70 psi)
More 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:
    • The Vent mode
    • The Recirculation mode
    • The A/C set to ON
    • The coldest temperature setting
    • The maximum blower speed
    • All A/C outlets set to OPEN
  4. Install the temperature probes of the J 43600  in the left and right center panel air outlets. See Special Tools .
  5. Apply the parking brake.
  6. Place the transaxle/transmission in one of the following positions:
    • PARK (Automatic)
    • NEUTRAL (Manual)
  7. Start the engine.
  8. Operate the A/C system for 5 minutes.
  9. Inspect the 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 .
  10. Print the following information:
    • The panel outlet air temperatures
    • The low-side pressure
    • The high-side pressure
  11. Compare the low and high side pressures and the panel output temperatures to the A/C performance table below.
Does all the data recorded fall within the specified ranges of the A/C performance table?		 - 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 temperatures again. See Special Tools .
  3. Compare the low and high side pressures and the panel output temperature to the A/C performance table.

Does all the data recorded fall within the specified ranges of the A/C performance table?		 - 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 temperatures 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 - Automatic
Fig 1: A/C Performance Test
GM1656124Courtesy of GENERAL MOTORS CORP.
A/C Performance Table

Ambient Air Temperature Relative Humidity Service Port Pressure Maximum Left Center Discharge Air Temperature Maximum Left Rear Discharge Air Temperature
Low Side High Side
13-18°C (55-65°F) 0-100% 130-179 kPa (19-26 psi) 530-861 kPa (77-125 psi) 8°C (46°F) 8°C (46°F)
19-24°C (66-75°F) Below 40% 130-192 kPa (19-28 psi) 668-1019 kPa (97-148 psi) 9°C (48°F) 10°C (50°F)
Above 40% 130-220 kPa (19-32 psi) 709-1061 kPa (103-154 psi) 12°C (52°F) 13°C (54°F)
25-29°C (76-85°F) Below 35% 151-220 kPa (22-32 psi) 909-1198 kPa (132-174 psi) 13°C (54°F) 13°C (55°F)
35-50% 151-234 kPa (22-34 psi) 930-1212 kPa (135-176 psi) 13°C (54°F) 13°C (55°F)
Above 50% 165-248 kPa (24-36 psi) 950-1240 kPa (138-180 psi) 14°C (57°F) 15°C (59°F)
33-35°C (86-95°F) Below 30% 172-254 kPa (25-37 psi) 1102-1419 kPa (160-206 psi) 15°C (59°F) 17°C (61°F)
30-50% 179-268 kPa (26-39 psi) 1109-1433 kPa (161-208 psi) 17°C (61°F) 18°C (63°F)
Above 50% 192-282 kPa (28-41 psi) 1129-1440 kPa (164-209 psi) 18°C (64°F) 18°C (64°F)
36-41°C (96-105°F) Below 20% 206-289 kPa (30-42 psi) 1329-1646 kPa (193-239 psi) 18°C (64°F) 19°C (66°F)
20-40% 213-296 kPa (31-43 psi) 1336-1646 kPa (194-239 psi) 19°C (66°F) 20°C (68°F)
Above 40% 220-303 kPa (32-44 psi) 1336-1646 kPa (194-239 psi) 20°C (68°F) 22°C (70°F)
42-46°C (106-115°F) Below 20% 248-323 kPa (36-47 psi) 1570-1839 kPa (228-267 psi) 20°C (68°F) 23°C (72°F)
Above 20% 248-330 kPa (36-48 psi) 1570-1832 kPa (228-266 psi) 23°C (72°F) 23°C (73°F)
47-49°C (116-120°F) Below 30% 282-358 kPa (41-52 psi) 1756-2018 kPa (255-293 psi) 24°C (75°F) 26°C (78°F)
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