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Test Description: Notes

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. 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 air temperatures.
Air Conditioning (A/C) System Performance Test (without PHT)

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.
  6. Record the ambient air temperature displayed on the J 43600  .
  7. Record the low and high side STATIC pressure readings.
Are both the low and high side pressures within the specified value?
  • Above 16°C (60°F) 345 kPa (50 psi)
  • Above 24°C (75°F) 483 kPa (70 psi)
  • Above 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 127-152 mm (5-6 inches).
  3. Select the following HVAC control settings:
    • The A/C ON
    • The coldest temperature setting
    • The maximum blower speed
    • The IP panel outlet mode
    • All IP panel outlets are OPEN
    • Recirculation mode
  4. Install the temperature probes to the J 43600  in the left and right center air outlets.
  5. Apply the parking brake.
  6. Place the transaxle/transmission in one of the following positions:
    • PARK for Automatic
    • NEUTRAL for Manual
  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  .
  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 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 temperatures again.
  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 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 - Manual in HVAC Systems - Manual or Symptoms - HVAC Systems - Automatic in HVAC Systems - Automatic
Fig 1: A/C System Pressure (4.3L, 4.8L, 5.3L, 6.0, and 8.1L Engines)
GM1485736Courtesy of GENERAL MOTORS CORP.
A/C Performance Table - 4.3L, 4.8L, 5.3L, 6.0, and 8.1L Engines

Ambient Air Temperature Relative Humidity Service Port Pressure Maximum Left Center Discharge Air Temperature
Low Side High Side
13-16°C (55-65°F) 0-100% 150-246 kPa (22-36 psi) 730-1190 kPa (106-173 psi) 12°C (54°F)
19-24°C (66-75°F) Below 40% 150-280 kPa (22-41 psi) 900-1390 kPa (131-202 psi) 14°C (57°F)
Above 40% 179-137 kPa (26-46 psi) 990-1500 kPa (144-218 psi) 16°C (61°F)
25-29°C (76-85°F) Below 35% 218-328 kPa (32-48 psi) 1240-1640 kPa (180-238 psi) 17°C (63°F)
35-60% 236-342 kPa (34-50 psi) 1290-1680 kPa (187-244 psi) 18°C (64°F)
Above 60% 250-365 kPa (36-53 psi) 1340-1760 kPa (194-255 psi) 20°C (68°F)
30-35°C (86-95°F) Below 30% 266-386 kPa (39-56 psi) 1500-1940 kPa (218-282 psi) 21°C (70°F)
30-50% 280-397 kPa (41-58 psi) 1540-1990 kPa (224-289 psi) 22°C (72°F)
Above 50% 300-430 kPa (44-62 psi) 1600-2070 kPa (232-300 psi) 24°C (75°F)
36-41°C (96-105°F) Below 20% 328-439 kPa (48-64 psi) 1810-2240 kPa (263-325 psi) 25°C (77°F)
20-40% 337-457 kPa (49-66 psi) 1840-2290 kPa (267-332 psi) 26°C (79°F)
Above 40% 355-474 kPa (52-69 psi) 1890-2340 kPa (274-340 psi) 27°C (81°F)
42-46°C (106-115°F) Below 20% 391-491 kPa (57-71 psi) 2130-2500 kPa (309-363 psi) 29°C (84°F)
Above 20% 397-508 kPa (58-74 psi) 2160-2550 kPa (313-370 psi) 30°C (86°F)
47-49°C (116-120°F) Below 30% 451-552 kPa (65-80 psi) 2420-2790 kPa (351-405 psi) 33°C (92°F)
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