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 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 .
  6. Record the ambient air temperature displayed on the J 43600 .
  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 in).
  3. Select the following HVAC control settings:
  4. • The A/C is ON
    • The coldest temperature setting
    • The maximum blower speed
    • Recirculation mode
    • The panel outlet mode
    • All panel outlets are OPEN
  5. Install the temperature probes of the J 43600 in the left and right center panel air outlets.
  6. Apply the parking brake.
  7. Place the transaxle/transmission in PARK.
  8. Start the engine.
  9. Operate the A/C system for 5 minutes.
  10. Inspect A/C components for the following conditions:
  11. • Abnormal frost areas
    • Unusual noises

    Important: Press the RESET button, before using the print function of the J 43600 .

  12. Print the following information:
  13. • The panel outlet air temperatures
    • The low-side pressure
    • The high-side pressure
  14. 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.
  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

A/C System Pressure - Zone Classification


Object Number: 1955838  Size: MF

A/C Performance Table

Ambient Temperature

Relative Humidity

Low Side Service Port Pressure

High Side Service Port Pressure

Maximum Left Center Discharge Air Temperature

Maximum Left Rear Discharge Air Temperature

13-18°C (55-65°F)

0-100%

151-277 kPa (22-33 psi)

1123-1446 kPa (163-210 psi)

8°C (45°F)

18°C (64°F)

19-24°C (66-75°F)

Below 40%

165-261 kPa (24-38 psi)

1150-1481 kPa (167-215 psi)

8°C (46°F)

19°C (66°F)

Above 40%

179-282 kPa (26-41 psi)

1240-1557 kPa (180-226 psi)

10°C (50°F)

22°C (70°F)

25-29°C (76-85°F)

Below 35%

206-296 kPa (30-43 psi)

1336-1598 kPa (194-232 psi)

10°C (50°F)

23°C (72°F)

35-50%

220-303 kPa (32-44 psi)

1391-1612 kPa (202-234 psi)

12°C (52°F)

23°C (73°F)

Above 50%

227-323 kPa (33-47 psi)

1419-1646 kPa (206-239 psi)

13°C (55°F)

25°C (77°F)

30-35°C (86-95°F)

Below 30%

241-330 kPa (35-48 psi)

1502-1756 kPa (218-255 psi)

13°C (55°F)

25°C (77°F)

30-50%

248-344 kPa (36-50 psi)

1508-1750 kPa (219-254 psi)

15°C (59°F)

28°C (81°F)

Above 50%

261-372 kPa (38-54 psi)

1529-1750 kPa (222-254 psi)

18°C (63°F)

28°C (82°F)

36-41°C (96-105°F)

Below 20%

275-365 kPa (40-53 psi)

1681-1929 kPa (244-280 psi)

15°C (59°F)

28°C (82°F)

20-40%

282-378 kPa (41-55 psi)

1681-1908 kPa (244-277 psi)

18°C (63°F)

30°C (86°F)

Above 40%

296-399 kPa (43-58 psi)

1681-1880 kPa (244-273 psi)

19°C (66°F)

32°C (88°F)

42-46°C (106-115°F)

Below 20%

316-399 kPa (46-58 psi)

1867-2080 kPa (271-302 psi)

18°C (63°F)

32°C (88°F)

Above 20%

323-413 kPa (47-60 psi)

1853-2039 kPa (269-296 psi)

19°C (66°F)

32°C (91°F)

47-49°C (116-120°F)

Below 30%

358-440 kPa (52-64 psi)

1998-2197 kPa (290-319 psi)

22°C (70°F)

34°C (93°F)