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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 55 (Heating, Ventilation, And Air Conditioning System) >> Diagnostic Information and Procedures >> Air Conditioning (A/C) System Performance Test (LWN) >> Test Description

Test Description

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. 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.

Step Action Values Yes No
NOTE:
  • 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 or the GE-48800 CoolTech A/C Recharge Machine.
  6. Record the ambient air temperature and humidity.
  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 
    NOTE:

    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 in).
  3. Select the following HVAC control settings:
    • The A/C ON.
    • The coldest temperature setting
    • The maximum blower speed
    • The I/P panel outlet mode
    • All I/P panel outlets are OPEN
    • Recirculation mode
  4. Install the temperature probes or thermometers in the left and right center A/C 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 and warm to operating temperature.
  8. Operate the A/C system for 5 minutes.
  9. Inspect A/C components for the following conditions:
    • Abnormal frost areas
    • Unusual noises
  10. Record 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 5  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  Acr2000 if using). Record the pressures and temperatures again.
  3. Compare the low and high side pressures and the output temperature to the table below.

Does all the data recorded fall within the specified ranges of the table below?		 - Go to Step 5  Go to Step 4 
4 Perform the necessary repairs. Refer to A/C Diagnostics Chart .
Is the action complete?		 - Go to Step 5  -
5 Operate the system in order to verify the test results.
Did you find the same results?		 - System OK Go to Symptoms - HVAC Systems - Manual
A/C Performance Table with Aux A/C

Ambient Air Temperature Relative Humidity Service Port Pressure Maximum Discharge Air Temperature
Low Side High Side Left Center Left Rear
13 - 18°C (55 - 65°F) 0 - 100% 186 - 252 kPa (27 - 33 psi) 1310 - 1586 kPa (190 - 230 psi) 9°C (48°F) 12°C (54°F)
19 - 24°C (66 - 75°F) Below 40% 192 - 235 kPa (28 - 34 psi) 1311 - 1586 kPa (190 - 230 psi) 9°C (48°F) 13°C (55°F)
Above 40% 200 - 241 kPa (29 - 35 psi) 1482 - 1758 kPa (215 - 255 psi) 12°C (54°F) 15°C (59°F)
25 - 29°C (76 - 85°F) Below 35% 283 - 324 kPa (41 - 47 psi) 1793 - 2068 kPa (260 - 300 psi) 16°C (61°F) 18°C (64°F)
35 - 60% 303 - 345 kPa (44 - 50 psi) 1965 - 2241 kPa (285 - 325 psi) 17°C 63°F) 19°C (66°F)
Above 60% 269 - 310 kPa (39 - 45 psi) 1999 - 2275 kPa (290 - 330 psi) 17°C (63°F) 19°C (66°F)
30 - 35°C (86 - 95°F) Below 30% 248 - 290 kPa (36 - 42 psi) 1586 - 1862 kPa (230 - 270 psi) 17°C (63°F) 19°C (66°F)
30 - 50% 241 - 283 kPa (35 - 41 psi) 1586 - 1862 kPa (230 - 270 psi) 17°C (63°F) 19°C (66°F)
Above 50% 241 - 283 kPa (35 - 41 psi) 1586 - 1862 kPa (230 - 270 psi) 17°C (63°F) 19°C (66°F)
36 - 41°C (96 - 105°F) Below 20% 262 - 317 kPa (38 - 46 psi) 1862 - 2137 kPa (270 - 310 psi) 19°C (66°F) 21°C (70°F)
20 - 40% 290 - 345 kPa (42 - 50 psi) 1931 - 2206 kPa (280 - 320 psi) 21°C (70°F) 23°C (73°F)
Above 40% 303 - 359 kPa (44 - 52 psi) 2068 - 2344 kPa (300 - 340 psi) 22°C (72°F) 23°C (73°F)
42 - 46°C (106 - 115°F) Below 20% 296 - 352 kPa (43 - 51 psi) 2034 - 2310 kPa (295 - 335 psi) 22°C (72°F) 23°C (73°F)
Above 20% 317 - 372 kPa (46 - 54 psi) 2103 - 2379 kPa (305 - 345 psi) 22°C (72°F) 24°C (75°F)
47 - 49°C (116 - 120°F) Below 30% 345 - 400 kPa (50 - 58 psi) 2275 - 2551 kPa (330 - 370 psi) 24°C (75°F) 26°C (79°F)
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