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 (AATs).

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 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 AAT 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 in).
  3. Select the following HVAC control setting:
  4. • The A/C is ON.
    • The coldest temperature setting
    • The maximum blower speed
    • Recirculation mode
    • The instrument panel (I/P) outlet mode
    • All I/P 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 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: 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 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. 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 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 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 in HVAC Systems - Manual

A/C System Pressure - Zone Classification


Object Number: 1233218  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%

175-232 kPa (25-34 psi)

810-1 030 kPa (117-150 psi)

12°C (53.6°F)

18-24°C (65-75°F)

Below 40%

175-245 kPa (25-36 psi)

970-1 230 kPa (140-179 psi)

11°C (51.8°F)

Above 40%

175-267 kPa (25-39 psi)

960-1 200 kPa (139-175 psi)

14°C (57.2°F)

24-29°C (75-85°F)

Below 35%

191-268 kPa (27-39 psi)

1 170-1 390 kPa (169-202 psi)

13°C (55.4°F)

35-50%

202-274 kPa (29-40 psi)

1 150-1 370 kPa (166-199 psi)

14°C (57.2°F)

Above 50%

210-287 kPa (30-42 psi)

1 140-1 340 kPa (165-195 psi)

16°C (60.8°F)

29-35°C (85-95°F)

Below 30%

219-296 kPa (31-43 psi)

1 330-1 580 kPa (193-230 psi)

15°C (59.0°F)

30-50%

225-303 kPa (32-44 psi)

1 310-1 550 kPa (190-225 psi)

17°C (62.6°F)

Above 50%

234-312 kPa (34-46 psi)

1 290-1 510 kPa (187-220 psi)

18°C (64.4°F)

35-41°C (95-105°F)

Below 20%

250-326 kPa (36-48 psi)

1 530-1 780 kPa (222-259 psi)

18°C (64.4°F)

20-40%

253-329 kPa (36-48 psi)

1 510-1 750 kPa (219-254 psi)

19°C (66.2°F)

Above 40%

260-333 kPa (37-49 psi)

1 490-1 720 kPa (216-250 psi)

20°C (68.0°F)

41-46°C (105-115°F)

Below 20%

284-353 kPa (41-52 psi)

1 720-1 940 kPa (249-282 psi)

21°C (69.8°F)

Above 20%

286-354 kPa (41-52 psi)

1 700-1 900 kPa (246-276 psi)

22°C (71.6°F)

46-49°C (115-120°F)

Below 30%

313-369 kPa (45-54 psi)

1 860-2 020 kPa (270-294 psi)

23°C (73.4°F)