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

Test Description

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

    • The current ambient air temperature (AAT)
    • 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

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 (AAT) 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.
  6. Record the ambient air temperature (AAT) 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 AAT 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 AUTO button--The system will automatically perform the following functions:
       - Enter the recirculation mode.
       - Set the temperature to the coldest setting.
       - Set the maximum blower speed.
    • All A/C outlets set to 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 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 the A/C components for the following conditions:
  12. • Abnormal frost areas
    • Unusual noises

    Important: Press the RESET button, before using the print function of the J 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 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 - Automatic

A/C System Pressure -- Zone Classification


Object Number: 690185  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 (55-65°F)

0-100%

175-261 kPa (26-33 psi)

1 120-1 450 kPa (163-210 psi)

8°C (46.4°F)

19-24°C (66-75°F)

Below 40%

175-261 kPa (25-38 psi)

1 151-1 358 kPa (167-215 psi)

9°C (48.2°F)

Above 40%

179-283 kPa (26-41 psi)

1 240-1 560 kPa (180-226 psi)

12°C (53°F)

25-29°C (76-85°F)

Below 35%

208-293 kPa (30-43 psi)

1 350-1 600 kPa (196-232 psi)

11°C (52°F)

35-49%

219-303 kPa (32-44 psi)

1 390-1 610 kPa (202-234 psi)

12°C (54°F)

Above 50%

227-322 kPa (33-47 psi)

1 420-1 640 kPa (206-238 psi)

14°C (57°F)

30-35°C (86-95°F)

Below 30%

241-331 kPa (35-48 psi)

1 500-1 760 kPa (218-255 psi)

14°C (57°F)

Above 30%

250-346 kPa (36-50 psi)

1 510-1 750 kPa (219-254 psi)

16°C (61°F)

Above 50%

263-368 kPa (38-53 psi)

1 530-1 750 kPa (222-254 psi)

18°C (64°F)

36-41°C (96-105°F)

Below 20%

276-363 kPa (40-53 psi)

1 680-1 930 kPa (244-280 psi)

16°C (61°F)

20-40%

284-380 kPa (41-55 psi)

1 680-1 910 kPa (244-277 psi)

18°C (64°F)

Above 40%

298-397 kPa (43-58 psi)

1 680-1 880 kPa (244-273 psi)

20°C (68°F)

42-46°C (106-115°F)

Below 20%

315-397 kPa (46-58 psi)

1 870-2 080 kPa (271-302 psi)

18°C (64°F)

Above 20%

323-415 kPa (47-60 psi)

1 850-2 030 kPa (269-295 psi)

20°C (68°F)

47-49°C (116-120°F)

Below 30%

357-427 kPa (52-62 psi)

2 000-2 140 kPa (290-311 psi)

21°C (70°F)