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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1887 (Heating, Ventilation, And Air Conditioning) >> Diagnostic Information and Procedures >> Air Conditioning (A/C) System Performance Test (L66 Red Line) >> Test Description

Test Description

WARNING: This page is about a different car, the 2007 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.
Air Conditioning (A/C) System Performance Test (L66 Red Line)

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. 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 
    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 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 .
  11. Print the following information:
    • The panel outlet air temperatures
    • The low-side pressure
    • The high-side pressure
  12. Compare the low and high side pressures and the panel output temperatures 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 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 - Manual
Fig 1: A/C System Pressure - Zone Classification
GM1653072Courtesy 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% 151-206 kPa (22-30 psi) 1109-1329 kPa (161-193 psi) 8°C (46°F)
19-24°C (66-75°F) Less than 40% 151-227 kPa (22-33 psi) 1205-1481 kPa (175-215 psi) 9°C (48°F)
Greater than 40% 151-254 kPa (22-37 psi) 1288-1495 kPa (187-217 psi) 12°C (52°F)
25-29°C (76-85°F) Less than 35% 172-261 kPa (25-38 psi) 1433-1688 kPa (208-245 psi) 12°C (52°F)
35-50% 186-268 kPa (27-39 psi) 1398-1722 kPa (203-250 psi) 13°C (54°F)
Greater than 50% 192-296 kPa (28-43 psi) 1378-1722 kPa (200-250 psi) 14°C (57°F)
30-35°C (86-95°F) Less than 30% 206-296 kPa (30-43 psi) 1522-1929 kPa (221-280 psi) 14°C (57°F)
30-50% 213-310 kPa (31-45 psi) 1343-1646 kPa (195-239 psi) 15°C (59°F)
Greater than 50% 234-337 kPa (34-49 psi) 1357-1591 kPa (197-231 psi) 18°C (63°F)
36-41°C (96-105°F) Less than 20% 241-330 kPa (35-48 psi) 1584-1818 kPa (230-264 psi) 17°C (61°F)
20-40% 248-344 kPa (36-50 psi) 1577-1777 kPa (229-258 psi) 18°C (64°F)
Greater than 40% 261-365 kPa (38-53 psi) 1591-1729 kPa (231-251 psi) 19°C (66°F)
42-46°C (106-115°F) Less than 20% 282-365 kPa (41-53 psi) 1729-1922 kPa (251-279 psi) 19°C (66°F)
Greater than 20% 289-378 kPa (42-55 psi) 1743-1860 kPa (253-270 psi) 20°C (68°F)
47-49°C (116-120°F) Below 30% 323-406 kPa (47-59 psi) 1839-2073 kPa (267-301 psi) 23°C (72°F)