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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1546 (Heating, Ventilation And Air Conditioning) >> Diagnostic Information and Procedures >> Air Conditioning (A/C) System Performance Test >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

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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?		 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 inches).
  3. Select the following HVAC control settings:
    • The A/C is ON
    • The coldest temperature setting
    • The maximum blower speed
    • Recirculation mode
    • The IP panel outlet mode
    • All IP panel outlets are OPEN
    • The passenger side of a Dual Zone HVAC control module is turned OFF
  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 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 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 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 and Equipment .
  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 in HVAC Systems - Automatic
Fig 1: A/C System Pressure - Zone Classification
GM675288Courtesy 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% 211-241 kPa (31-35 psi) 500-740 kPa (73-107 psi) 8° C (46° F)
19-23° C (66-75° F) Below 40% 193-223 kPa (28-32 psi) 780-1090 kPa (106-167 psi) 8° C (46° F)
Above 40% 209-239 kPa (30-35 psi) 730-1050 kPa (106-167 psi) 9° C (48° F)
24-29° C (76-85° F) Below 35% 172-214 kPa (25-31 psi) 1020-1227 kPa (148-178 psi) 9° C (48° F)
35-60% 199-229 kPa (29-33 psi) 970-1300 kPa (141-189 psi) 9° C (48° F)
Above 60% 207-237 kPa (30-34 psi) 1020-1500 kPa (148-218 psi) 10° C (50° F)
30-35° C (86-95° F) Below 30% 210-240 kPa (31-35 psi) 1130-1520 kPa (164-221 psi) 10° C (50° F)
30-50% 208-238 kPa (30-35 psi) 1190-1670 kPa (173-242 psi) 11° C (52° F)
Above 50% 205-235 kPa (30-35 psi) 1280-1910 kPa (186-277 psi) 11° C (52° F)
36-40° C (96-105° F) Below 20% 226-256 kPa (33-37 psi) 1280-1650 kPa (186-240 psi) 12° C (54° F)
20-40% 218-248 kPa (32-36 psi) 1360-1870 kPa (197-271 psi) 12° C (54° F)
Above 40% 211-241 kPa (31-35 psi) 1520-2100 kPa (221-305 psi) 12° C (54° F)
41-46° C (106-115° F) Below 20% 238-268 kPa (35-39 psi) 1460-1830 kPa (212-267 psi) 13° C (55° F)
Above 20% 226-256 kPa (33-37 psi) 1570-2100 kPa (228-306 psi) 13° C (55° F)
47-49° C (116-120° F) Below 30% 238-268 kPa (35-39 psi) 1750-2090 kPa (254-303 psi) 14° C (57° F)
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