Air Conditioning (A/C) System Performance Test. Buick Lucerne 2009

For 1990-2009 cars only

Makes 🢒 Buick 🢒 2009 🢒 Lucerne 🢒 HVAC 🢒 Heating, Ventilation, and Air Conditioning 🢒 Air Conditioning (A/C) System Performance Test

Air Conditioning (A/C) System Performance Test 3.8L L26

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.

This step determines if the A/C system has at least the minimum refrigerant charge required to operate the system without damage.

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

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

Step

Action

Values

Yes

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.

•	Use a scan tool to command the cooling fans to high speed.

Park the vehicle inside or in the shade.
Open the windows in order to ventilate the interior of the vehicle.
If the A/C system was operating, allow the A/C system to equalize for about 2 minutes.
Turn OFF the ignition.
Install the J 43600 ACR 2000 Air Conditioning Service Center.
Record the ambient air temperature displayed on the J 43600 .
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

Important: Record the relative humidity and the ambient air temperature at the time of the test.

Close the vehicle doors and windows.
Open the drivers door window 12.7-15.2 cm (5-6 in).
Select the following HVAC control settings:

•	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

Install the temperature probes of the J 43600 in the left and right center panel air outlets.
Apply the parking brake.
Place the transaxle/transmission in one of the following positions:

•	PARK (Automatic)

•	NEUTRAL (Manual)

Start the engine.
Using a scan tool, command the engine cooling fans to high speed.
Operate the A/C system for 5 minutes.
Inspect the A/C components for the following conditions:

•	Abnormal frost areas

•	Unusual noises

Important: Press the RESET button before using the print function of the J 43600 .

Print the following information:

•	The panel outlet air temperatures

•	The low-side pressure

•	The high-side pressure

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

If the pressures and temperatures recorded do not fall within the specified ranges:

Continue to operate the A/C system for an additional 5 minutes.
Reset the J 43600 and record the pressures and temperatures again.
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

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

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

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

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

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

A/C Performance Table

Ambient Air Temperature	Relative Humidity	Service Port Pressure		Maximum Left Center Discharge Air Temperature
Ambient Air Temperature	Relative Humidity	Low Side	High Side	Maximum Left Center Discharge Air Temperature
13-18°C (55-65°F)	0-100%	130-227 kPa (19-33 psi)	482-799 kPa (70-116 psi)	9°C (48°F)
19-24°C (66-75°F)	Below 40%	130-234 kPa (19-34 psi)	613-950 kPa (89-138 psi)	10°C (50°F)
19-24°C (66-75°F)	Above 40%	130-254 kPa (19-37 psi)	661-999 kPa (96-145 psi)	13°C (54°F)
25-29°C (76-85°F)	Below 35%	179-254 kPa (26-37 psi)	840-1123 kPa (122-163 psi)	13°C (54°F)
	35-50%	192-261 kPa (28-38 psi)	861-1129 kPa (125-164 psi)	13°C (55°F)
	Above 50%	199-268 kPa (29-39 psi)	881-1157 kPa (128-168 psi)	14°C (57°F)
30-35°C (86-95°F)	Below 30%	206-282 kPa (30-41 psi)	1019-1329 kPa (148-193 psi)	15°C (59°F)
	30-50%	213-289 kPa (31-42 psi)	1040-1336 kPa (151-194 psi)	15°C (59°F)
	Above 50%	220-289 kPa (32-42 psi)	1047-1357 kPa (152-197 psi)	18°C (63°F)
36-41°C (96-105°F)	Below 20%	234-310 kPa (34-45 psi)	1240-1550 kPa (180-225 psi)	18°C (63°F)
	20-40%	241-310 kPa (35-45 psi)	1247-1550 kPa (181-225 psi)	18°C (64°F)
	Above 40%	241-310 kPa (35-45 psi)	1260-1550 kPa (183-225 psi)	19°C (66°F)
42-46°C (106-115°F)	Below 20%	268-337 kPa (39-49 psi)	1460-1729 kPa (212-251 psi)	19°C (66°F)
42-46°C (106-115°F)	Above 20%	268-330 kPa (39-48 psi)	1467-1729 kPa (213-251 psi)	20°C (68°F)
47-49°C (116-120°F)	Below 30%	296-358 kPa (43-52 psi)	1646-1908 kPa (239-277 psi)	23°C (72°F)