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
    • 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 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.
   • Allow the vehicle to adjust to ambient temperature.
   • The outside air temperature sensor must be updated prior to performing the A/C Performance Test to allow the ECM to update to the current ambient temperature.

1

  1. To activate the OAT sensor instant update feature, refer to Scan Tool Output Controls in HVAC Systems - Automatic or perform the following procedure:
  2. 1.1. Put the ignition to the ON position.
    1.2. Press the following three buttons simultaneously:
       • Fan Up
       • Front Defrost
       • Rear Defog
  3. Park the vehicle inside or in the shade.
  4. Open the windows in order to ventilate the interior of the vehicle.
  5. If the A/C system was operating, allow the A/C system to equalize for about 2 minutes.
  6. Turn OFF the ignition.
  7. Install the J 43600 ACR 2000 Air Conditioning Service Center.
  8. Record the ambient air temperature displayed on the J 43600 .
  9. Record the low and high side STATIC pressure readings.

Are both the low side 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 drivers door window 12.7-15.2 cm (5-6 in).
  3. Install the temperature probes of the J 43600 in the left and right center panel air outlets.
  4. Apply the parking brake.
  5. Place the transaxle in PARK
  6. Start the engine.
  7. Select the following HVAC control settings:
  8. • A/C setting
    • Recirculation mode
    • Maximum blower speed
    • Panel mode
    • Coldest temperature setting
    • All panel outlets are Open
  9. Using the scan tool, command the engine cooling fan to 50 percent for ambient temperatures below 32.2°C (90°F) and 90 percent for ambient temperatures above 32.2°C (90°F).
  10. Operate the A/C system for 5 minutes.
  11. Inspect 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 temperature
    • The low-side pressure
    • The high-side pressure
  15. Compare the low and high side pressures and the panel 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 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 temperature again.
  3. Compare the low and high side pressures and the panel 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 temperature 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 in HVAC Systems - Automatic

A/C System Pressure - Zone Classification


Object Number: 1196090  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%

175-195 kPa (25-29 psi)

1820-2070 kPa (264-301 psi)

6°C (43°F)

18-24°C (65-75°F)

Below 40%

175-219 kPa (25-32 psi)

1770-2010 kPa (256-292 psi)

8°C (47°F)

Above 40%

175-236 kPa (25-35 psi)

1870-2070 kPa (271-301 psi)

9°C (49°F)

24-29°C (75-85°F)

Below 35%

175-239 kPa (25-35 psi)

1890-2050 kPa (274-298 psi)

10°C (50°F)

35-60%

177-246 kPa (25-36 psi)

1920-2060 kPa (278-299 psi)

11°C (52°F)

Above 60%

184-262 kPa (26-38 psi)

1940-2080 kPa (281-302 psi)

12°C (54°F)

29-35°C (85-95°F)

Below 30%

188-261 kPa (27-38 psi)

1960-2130 kPa (284-310 psi)

12°C (54°F)

30-50%

196-274 kPa (28-40 psi)

1970-2110 kPa (285-307 psi)

13°C (56°F)

Above 50%

206-294 kPa (29-43 psi)

1980-2080 kPa (287-302 psi)

15°C (59°F)

35-41°C (95-105°F)

Below 20%

208-278 kPa (30-41 psi)

2060-2220 kPa (299-323 psi)

13°C (56°F)

20-40%

214-294 kPa (31-43 psi)

2060-2180 kPa (299-317 psi)

15°C (59°F)

Above 40%

227-309 kPa (32-45 psi)

2040-2130 kPa (296-310 psi)

16°C (61°F)

41-46°C (105-115°F)

Below 20%

230-298 kPa (33-44 psi)

2170-2300 kPa (314-334 psi)

14°C (58°F)

Above 20%

238-316 kPa (34-46 psi)

2140-2230 kPa (310-324 psi)

16°C (61°F)

46-49°C (115-120°F)

Below 30%

258-319 kPa (37-47 psi)

2220-2300 kPa (322-334 psi)

16°C (61°F)