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

Value(s)

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. Ensure that the ignition key is in the OFF position.
  5. Install the J 43600 ACR 2000 Air Conditioning Service Center.
  6. Record the ambient air temperature displayed on the J 43600 .
  7. Record readings of the low and high side STATIC pressures.

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

    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  inches).
  3. Select the following HVAC control settings:
  4. • The A/C is in recirculation mode
    • The A/C on
    • The coldest temperature setting
    • The maximum blower speed
    • The IP panel outlet mode
    • All IP panel outlets are OPEN
    • The passenger side of a Dual Zone HVAC control module is turned OFF
  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 and elevate the engine RPM to 2,000 and maintain.
  9. Operate the A/C system for 5 minutes.
  10. Inspect the A/C components for the following conditions:
  11. •  Abnormal frost areas
    • Unusual noises

    Important: When performing this step it is necessary to press the RESET button on the J 43600 before pressing the PRINT button.

  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 output temperatures to the table below.

Does all the data recorded fall within the specified ranges of the table below?

--

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. 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 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 is 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 higher 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 in HVAC Systems - Manual

A/C System Pressure - Zone Classification


Object Number: 634265  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%

175-243 kPa (25-35 psi)

640-990 kPa (93-144 psi)

12°C (53.6°F)

19-24°C (66-75°F)

Below 40%

175-256 kPa (25-37 psi)

750-1120 kPa (109-163 psi)

12°C (53.6°F)

Above 40%

184-287 kPa (27-42 psi)

820-1240 kPa (119-180 psi)

15°C (59°F)

25-29°C (76-85°F)

Below 35%

196-277 kPa (28-40 psi)

960-1280 kPa (139-186 psi)

14°C (57.2°F)

35-60%

212-290 kPa (31-42 psi)

1020-1340 kPa (148-195 psi)

16°C (60.8°F)

Above 60%

223-316 kPa (32-46 psi)

1070-1460 kPa (155-212 psi)

18°C (64.4°F)

30-35°C (86-95°F)

Below 30%

220-303 kPa (32-44 psi)

1130-1480 kPa (164-215 psi)

17°C (62.6°F)

30-50%

223-322 kPa (34-47 psi)

1190-1570 kPa (173-228 psi)

19°C (66.2°F)

Above 50%

250-350 kPa (36-51 psi)

1260-1710 kPa (183-248 psi)

21°C (69.8°F)

36-41°C (96-105°F)

Below 20%

245-324 kPa (36-47 psi)

1300-1630 kPa (189-237 psi)

19°C (66.2°F)

20-40%

254-344 kPa (37-50 psi)

1350-1750 kPa (196-254 psi)

21°C (69.8°F)

Above 40%

273-364 kPa (40-53 psi)

1440-1860 kPa (209-270 psi)

23°C (73.4°F)

42-46°C (106-115°F)

Below 20%

273-348 kPa (40-51 psi)

1440-1860 kPa (209-270 psi)

22°C (71.6°F)

Above 20%

284-370 kPa (41-54 psi)

1550-1930 kPa (218-261 psi)

24°C (75.2°F)

47-49°C (116-120°F)

Below 30%

308-374 kPa (45-54 psi)

1720-1970 kPa (250-286 psi)

24°C (75.2°F)