GM Service Manual Online
For 1990-2009 cars only
Table 1: A/C Performance Table

This test measures the operating efficiency of the A/C system under the following conditions.

    • The current ambient air temperature
    • The current relative humidity
    • The high side pressure of the A/C system
    • The low side pressure of the A/C system
    • The temperature of the air being discharged into the passenger compartment

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step determines if the A/C system has at least the minimum refrigerant charge required to operate the system without damage.

  2. This step measures the performance of the A/C system.

  3. This step is to allow for vehicle variations as well as high ambient air 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 (about 2 minutes).
  4. Turn OFF the ignition.
  5. Install the J 43600 .
  6. Record the ambient air temperature displayed on the J 43600 .
  7. Record the low and high side STATIC pressures.

Are both the low and high side pressures within the specified value?

Greater than 16°C (60°F) - 345 kPa (50 psi)

Greater than 24°C (75°F) - 483 kPa (70 psi)

Greater 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 driver door window 13-15 cm (5-6 in).
  3. Set the HVAC control to the following positions:
  4. • The A/C on
    • The maximum blower speed
    • The HVAC control assembly to discharge air through the A/C outlets
    • The temperature control to the coldest position
    • All I/P panels OPEN
  5. Install temperature to the J 43600 in the left and right center I/P air outlets.
  6. Apply the parking brake.
  7. Place the transaxle/transmission in one of the following positions:
  8. • PARK - Automatic
    • NEUTRAL - Manual
  9. Start the engine.
  10. Operate the A/C system for 5 minutes.
  11. Inspect for the following:
  12. •  Abnormal frost areas
    • Unusual noises

    Important: Press the reset button before using the print functionJ 43600 .

  13. Print the following information:
  14. • The panel outlet air temperatures
    • The low-side pressure
    • The high-side pressure
  15. Compare the low and high side pressures and the I/P panel output temperatures to the A/C 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 J 43600 and record the pressure and temperature.
  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 table?

--

Go to Step 8

Go to Step 4

4

Do the high and low side pressures fall within the specified ranges, but the outlet panel 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 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

A/C System Pressure - Zone Classification


Object Number: 723678  Size: MF

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 (55-50°F)

0-100%

222-252 kPa (25-31 psi)

1080-129 kPa (78-136 psi)

13°C (55°F)

19-24°C (66-75°F)

Less than 40%

231-261 kPa (25-31 psi)

1220-1460 kPa (109-173 psi)

14°C (57°F)

Greater than 40%

251-281 kPa (25-35 psi)

1220-1500 kPa (116-187 psi)

16°C (61°F)

25-29°C (76-85°F)

Less than 35%

251-281 kPa (25-34 psi)

1360-1590 kPa (151-208 psi)

16°C (61°F)

35-60%

259-289 kPa (25-36 psi)

1380-1620 kPa (158-215 psi)

17°C (63°F)

Greater than 60%

275-305 kPa (26-38 psi)

1390-1680 kPa (164-231 psi)

19°C (66°F)

30-35°C (86-95°F)

Less than 30%

276-306 kPa (27-39 psi)

1470-1730 kPa (193-261 psi)

19°C (66°F)

Greater than 30%

287-317 kPa (30-41 psi)

1500-1800 kPa (203-282 psi)

20°C (68°F)

36-41°C (96-105°F)

Less than 20%

297-327 kPa (32-44 psi)

1590-1840 kPa (224-283 psi)

70°C (21°F)

20-40%

309-339 kPa (33-44 psi)

1320-1930 kPa (229-300 psi)

22°C (72°F)

Greater than 40%

320-350 kPa (34-44 psi)

1690-2020 kPa (244-316 psi)

24°C (75°F)

42-46°C (106-115°F)

Less than 20%

319-349 kPa (38-49 psi)

1720-1960 kPa (264-319 psi)

23°C (73°F)

Greater than 20%

332-362 kPa (38-48 psi)

1760-2070 kPa (271-338 psi)

24°C (75°F)

47-49°C (116-120°F)

Less than 30%

339-369 kPa (43-51 psi)

1880-2090 kPa (307-350 psi)

25°C (77°F)