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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1909 (Heating, Ventilation, And Air Conditioning) >> Diagnostic Information and Procedures >> Air Conditioning (A/C) System Performance Test (LZ4) >> Test Description

Test Description

WARNING: This page is about a different car, the 2009 Saturn Vue. 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.
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 (With HP5)  or Leak Testing (Without HP5) 
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 driver door window 12.7-15.2 cm (5-6 in).
  3. Select the following HVAC control settings:
    • The A/C is ON.
    • The coldest temperature setting
    • The maximum blower speed
    • Recirculation mode
    • The instrument panel (I/P) outlet mode
    • All I/P outlets are 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 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 (with HP5)  or Air Conditioning (A/C) Diagnostics - Pressure Zone A (without HP5)  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 (without HP5)  or Air Conditioning (A/C) Diagnostics - Pressure Zone D (with HP5)  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
Fig 1: A/C System Pressure - Zone Classification
GM1938465Courtesy of GENERAL MOTORS CORP.
A/C Performance Table

Ambient Temperature Relative Humidity Low Side Service Port Pressure High Side Service Port Pressure Maximum Left Center Discharge Air Temperature
13-18°C (55-65°F) 0-100% 151-192 kPa (22-28 psi) 950-1440 kPa (138-209 psi) 8°C (46°F)
19-24°C (66-75°F) Below 40% 158-220 kPa (23-32 psi) 1012-1488 kPa (147-216 psi) 10°C (50°F)
Above 40% 151-227 kPa (22-33 psi) 1157-1688 kPa (168-245 psi) 13°C (54°F)
25-29°C (76-85°F) Below 35% 179-248 kPa (26-36 psi) 1228-1681 kPa (187-244 psi) 13°C (55°F)
35-50% 186-254 kPa (27-37 psi) 1391-1750 kPa (202-254 psi) 14°C (57°F)
Above 50% 186-268 kPa (27-39 psi) 1460-1887 kPa (212-274 psi) 17°C (61°F)
30-35°C (86-95°F) Below 30% 199-275 kPa (29-40 psi) 1508-1908 kPa (219-277 psi) 17°C (61°F)
30-50% 206-289 kPa (30-42 psi) 1577-1998 kPa (229-290 psi) 18°C (64°F)
Above 50% 213-216 kPa (31-46 psi) 1667-2129 kPa (242-309 psi) 21°C (70°F)
36-41°C (96-105°F) Below 20% 220-296 kPa (32-43 psi) 1750-2129 kPa (254-309 psi) 18°C (64°F)
20-40% 234-316 kPa (34-46 psi) 1791-2211 kPa (260-321 psi) 20°C (68°F)
Above 40% 248-337 kPa (36-49 psi) 1880-2287 kPa (273-332 psi) 23°C (73°F)
42-46°C (106-115°F) Below 20% 278-316 kPa (36-46 psi) 2011-2342 kPa (292-340 psi) 22°C (70°F)
Above 20% 354-344 kPa (37-50 psi) 2053-2418 kPa (268-351 psi) 24°C (75°F)
47-49°C (116-120°F) Below 30% 282-358 kPa (41-52 psi) 2590-2590 kPa (328-376 psi) 25°C (77°F)
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