GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2000 🢒 LeSabre 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 System Performance Test
Table 1: A/C Performance Table

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. This step determines if there is enough refrigerant in the A/C system to operate it without damage.

    2.

  2. This step measures the performance of the A/C system.

    3.

  3. This step is to allow for vehicle variations as well as high ambient temperatures.

Step

Action

Value(s)

Yes

No

Important: 

   • The ambient 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.

The following test measures the A/C system operating efficiency by comparing:

    • The ambient air temperature
    • The ambient air humidity
    • The pressure at the high-pressure side of the refrigeration system
    • The pressure at the low-pressure side of the refrigeration system
    • The temperature of the air being discharged into the passenger compartment

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 39500-B
  6. Record the ambient temperature at the vehicle.
  7. Record readings of the low and high side STATIC pressures.

Are both the low and high side pressures within 103 kPa (15 psi) of the ambient temperature?

--

Go to Step 2

Go to Leak Testing

2

    Important: Record the relative humidity and the ambient temperature AT THE TIME OF THE TEST.

  1. Record the ambient temperature at the vehicle.
  2. Record the relative humidity, using one of the following methods:
    3. • Use a psychrometer
    • Consult the local weather bureau
  3. Close the vehicle doors and windows.
  4. Open the driver's door window 5-6 inches.
  5. Set the HVAC control assembly to the following positions:
    6. • The A/C on
    • The blower control to the highest position
    • The HVAC control assembly to discharge air through the A/C outlets
    • The temperature control to the coldest position
    • Passenger temperature control off (with CJ2)
    • Recirc mode
    • Vent button LED not illuminated
    • All A/C outlets OPEN
  6. Install thermometers in the left and right center A/C air outlets.
  7. Apply the parking brake.
  8. Place the transaxle/transmission in one of the following positions:
    9. • PARK
    • NEUTRAL
  9. Start the engine and allow to idle.
  10. Operate the A/C system for 5 minutes.
  11. Inspect for the following:
    12. •  Abnormal frost areas
    • Unusual noises
  12. Record the following information:
    13. • The outlet air temperatures
    • The low-side pressure
    • The high-side pressure
  13. 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 4

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 4

Go to VDOT Air Conditioning (A/C) System Diagnosis

4

Operate the system in order to verify the test results.

Did you find the same results?

--

System OK

Go to Symptoms in HVAC-Automatic or Symptoms in HVAC-Manual

A/C Performance Table

Ambient Temperature

Relative Humidity

Low Side Service Port Pressure

High Side Service Port Pressure

Maximum Left Center Discharge Air Temperature

16°C (60°F)

0-100 %

193-234 kPa

(28-34 psi)

896-1103 kPa

(130-160 psi)

9°C (49°F)

21°C (70°F)

Below 40 %

221-262 kPa

(32-38 psi)

1103-1310 kPa

(160-190 psi)

11°C (52°F)

Above 40 %

234-276 kPa

(34-40 psi)

1207-1413 kPa

(175-205 psi)

11°C (52°F)

27°C (80°F)

Below 40 %

255-296 kPa

(37-43 psi)

1138-1345 kPa

(165-195 psi)

13°C (55°F)

Above 40 %

296-331 kPa

(43-48 psi)

1207-1413 kPa

(175-205 psi)

14°C (58°F)

32°C (90°F)

Below 30 %

262-303 kPa

(38-44 psi)

1241-1448 kPa

(180-210 psi)

12°C (53°F)

Above 30 %

283-324 kPa

(41-47 psi)

1241-1448 kPa

(180-210 psi)

16°C (60°F)

38°C (100°F)

Below 30 %

317-379 kPa

(46-56 psi)

1413-1689 kPa

(205-245 psi)

18°C (65°F)

Above 30 %

317-379 kPa

(46-56 psi)

1448-1724 kPa

(210-250 psi)

16°C (63°F)

43°C (110°F)

Below 25 %

331-400 kPa

(48-58 psi)

1655-1931 kPa

(240-280 psi)

17°C (62°F)

Above 25 %

352-421 kPa

(51-61 psi)

1655-1931 kPa

(240-280 psi)

22°C (71°F)

49°C (120°F)

Below 30 %

400-469 kPa

(58-68 psi)

1896-2172 kPa

(275-315 psi)

23°C (73°F)