Air Conditioning (A/C) System Performance Test. Buick LaCrosse 2007

For 1990-2009 cars only

Makes 🢒 Buick 🢒 2007 🢒 LaCrosse 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Air Conditioning (A/C) System Performance Test

Air Conditioning (A/C) System Performance Test LY7

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.

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 (AATs).

Step

Action

Values

Yes

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.

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 (AAT) displayed on the J 43600 .
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

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

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

•	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

Install the temperature probes of the J 43600 in the left and right center panel air outlets.
Apply the parking brake.
Place the transmission in PARK.
Start the engine.
Operate the A/C system for 5 minutes.
Inspect A/C components for the following conditions:

•	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.

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.
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 is 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 - Manual or 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%	158-254 kPa (23-37 psi)	881-1288 kPa (128-187 psi)	18°C (64°F)
19-24°C (65-75°F)	Below 40%	151-227 kPa (22-33 psi)	923-1329 kPa (134-193 psi)	15°C (59°F)
19-24°C (65-75°F)	Above 40%	172-275 kPa (25-40 psi)	1047-1460 kPa (152-212 psi)	20°C (68°F)
25-29°C (75-85°F)	Below 35%	158-241 kPa (25-35 psi)	1157-1481 kPa (168-215 psi)	18°C (63°F)
	35-50%	186-254 kPa (27-37 psi)	1233-1522 kPa (179-221 psi)	19°C (66°F)
	Above 50%	199-282 kPa (29-41 psi)	1281-1598 kPa (186-232 psi)	23°C (72°F)
30-35°C (85-95°F)	Below 30%	179-254 kPa (26-37 psi)	1336-1667 kPa (194-242 psi)	20°C (68°F)
	30-50%	192-268 kPa (28-39 psi)	1378-1708 kPa (200-248 psi)	22°C (70°F)
	Above 50%	213-296 kPa (31-43 psi)	1440-1770 kPa (209-256 psi)	24°C (75°F)
36-41°C (95-105°F)	Below 20%	199-268 kPa (29-39 psi)	1550-1867 kPa (225-271 psi)	23°C (73°F)
	20-40%	206-282 kPa (30-41 psi)	1570-1887 kPa (228-274 psi)	24°C (75°F)
	Above 40%	220-296 kPa (32-43 psi)	1612-1908 kPa (234-277 psi)	25°C (77°F)
42-46°C (105-115°F)	Below 20%	220-289 kPa (32-42 psi)	1777-2053 kPa (258-298 psi)	25°C (77°F)
42-46°C (105-115°F)	Above 20%	227-296 kPa (33-43 psi)	1791-2060 kPa (260-299 psi)	27°C (79°F)
47-49°C (115-120°F)	Below 30%	248-310 kPa (36-45 psi)	1970-2218 kPa (286-322 psi)	28°C (82°F)

Air Conditioning (A/C) System Performance Test 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 (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.

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 (AATs).

Step

Action

Values

Yes

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.

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 (AAT) displayed on the J 43600 .
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

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

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

•	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

Install the temperature probes of the J 43600 in the left and right center panel air outlets.
Apply the parking brake.
Place the transmission in PARK.
Start the engine.
Operate the A/C system for 5 minutes.
Inspect A/C components for the following conditions:

•	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.

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.
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 is 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 - Manual or 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%	151-179 kPa (22-26 psi)	868-1267 kPa (126-184 psi)	8°C (46°F)
19-24°C (65-75°F)	Below 40%	151-186 kPa (22-27 psi)	888-1281 kPa (129-186 psi)	8°C (46°F)
19-24°C (65-75°F)	Above 40%	151-206 kPa (22-30 psi)	1019-1419 kPa (148-206 psi)	10°C (50°F)
25-29°C (76-85°F)	Below 35%	151-192 kPa (22-28 psi)	1109-1412 kPa (161-205 psi)	8°C (46°F)
	35-50%	151-199 kPa (22-29 psi)	1178-1460 kPa (171-212 psi)	10°C (50°F)
	Above 50%	151-220 kPa (22-32 psi)	1240-1550 kPa (180-225 psi)	13°C (54°F)
30-35°C (85-95°F)	Below 30%	151-206 kPa (22-30 psi)	1267-1591 kPa (184-231 psi)	10°C (50°F)
	30-50%	151-220 kPa (22-32 psi)	1322-1639 kPa (192-238 psi)	13°C (54°F)
	Above 50%	165-241 kPa (24-35 psi)	1378-1708 kPa (200-248 psi)	14°C (57°F)
36-41°C (95-105°F)	Below 20%	151-213 kPa (22-31 psi)	1460-1756 kPa (212-255 psi)	12°C (52°F)
	20-40%	158-227 kPa (23-33 psi)	1481-1791 kPa (215-260 psi)	13°C (55°F)
	Above 40%	172-241 kPa (25-35 psi)	1529-1832 kPa (222-266 psi)	14°C (57°F)
42-46°C (105-115°F)	Below 20%	172-227 kPa (25-33 psi)	1660-1922 kPa (241-279 psi)	13°C (54°F)
42-46°C (105-115°F)	Above 20%	179-241 kPa (26-35 psi)	1681-1942 kPa (244-282 psi)	14°C (57°F)
47-49°C (115-120°F)	Below 30%	186-248 kPa (27-36 psi)	1839-2087 kPa (267-303 psi)	15°C (59°F)