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.

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 Vent mode
    • The Recirculation mode
    • The A/C set to ON
    • The coldest temperature setting
    • 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: 1411344  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%

150-265 kPa (22-38 psi)

510-1070 kPa (74-155 psi)

9°C (48°F)

19-24°C (66-75°F)

Below 40%

155-283 kPa (226-41 psi)

640-1200 kPa (93-174 psi)

9°C (48°F)

Above 40%

180-311 kPa (26-45 psi)

670-1180 kPa (97-171 psi)

11°C (52°F)

25-29°C (76-85°F)

Below 35%

194-315 kPa (28-46 psi)

820-1340 kPa (119-194 psi)

11°C (52°F)

35-50%

212-326 kPa (31-47 psi)

850-1320 kPa (123-192 psi)

12°C (54°F)

Above 50%

225-349 kPa (33-51 psi)

840-1300 kPa (122-189 psi)

14°C (57°F)

33-35°C (86-95°F)

Below 30%

223-360 kPa (32-52 psi)

970-1530 kPa (141-222 psi)

14°C (57°F)

30-50%

237-374 kPa (34-54 psi)

990-1510 kPa (144-219 psi)

16°C (61°F)

Above 50%

255-395 kPa (37-57 psi)

990-1490 kPa (144-216 psi)

19°C (66°F)

36-41°C (96-105°F)

Below 20%

253-406 kPa (37-59 psi)

1140-1750 kPa (165-254 psi)

16°C (61°F)

20-40%

262-415 kPa (38-60 psi)

1160-1730 kPa (168-251 psi)

18°C (64°F)

Above 40%

281-428 kPa (41-62 psi)

1180-1700 kPa (171-247 psi)

20°C (68°F)

42-46°C (106-115°F)

Below 20%

288-447 kPa (42-65 psi)

1320-1920 kPa (192-279 psi)

19°C (66°F)

Above 20%

297-455 kPa (43-66 psi)

1340-1900 kPa (194-276 psi)

21°C (70°F)

47-49°C (116-120°F)

Below 30%

327-473 kPa (47-69 psi)

1490-2010 kPa (216-292 psi)

21°C (70°F)