Air Conditioning (A/C) System Performance Test. GMC Truck GMC C Sierra

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2003 🢒 GMC C Sierra - 2WD 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 Air Conditioning (A/C) System Performance Test

Table 1:	A/C Performance Table - 4.3L, 4.8L. 5.3L, 6.0, and 8.1L Engines
Table 2:	A/C Performance Table - 6.6L

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

Test Description

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 air 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.

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 Refrigerant Station.
Record the ambient air temperature displayed on the J 43600 .
Record the low and high side STATIC pressure readings.

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 ambient air temperature at the time of the test.

Close the vehicle doors and windows.
Open the drivers door window 127-152 mm (5-6 inches).
Select the following HVAC control settings:

•	The A/C ON

•	The coldest temperature setting

•	The maximum blower speed

•	The IP panel outlet mode

•	All IP panel outlets are OPEN

•	Recirculation mode

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

•	PARK for Automatic

•	NEUTRAL for Manual

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: 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 table below.

Does all the data recorded fall within the specified ranges of the table below?

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 table below.

Does all the data recorded fall within the specified ranges of the table below?

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 - Manual in HVAC Systems - Manual or Symptoms - HVAC Systems - Automatic in HVAC Systems - Automatic

A/C System Pressure -- Zone Classification

A/C Performance Table - 4.3L, 4.8L. 5.3L, 6.0, and 8.1L Engines

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
13-16°C (55-65°F)	0-100%	150-246 kPa (22-36 psi)	730-1190 kPa (106-173 psi)	12°C (54°F)
19-24°C (66-75°F)	Below 40%	150-280 kPa (22-41 psi)	900-1390 kPa (131-202 psi)	14°C (57°F)
19-24°C (66-75°F)	Above 40%	179-137 kPa (26-46 psi)	990-1500 kPa (144-218 psi)	16°C (61°F)
25-29°C (76-85°F)	Below 35%	218-328 kPa (32-48 psi)	1240-1640 kPa (180-238 psi)	17°C (63°F)
	35-60%	236-342 kPa (34-50 psi)	1290-1680 kPa (187-244 psi)	18°C (64°F)
	Above 60%	250-365 kPa (36-53 psi)	1340-1760 kPa (194-255 psi)	20°C (68°F)
30-35°C (86-95°F)	Below 30%	266-386 kPa (39-56 psi)	1500-1940 kPa (218-282 psi)	21°C (70°F)
	30-50%	280-397 kPa (41-58 psi)	1540-1990 kPa (224-289 psi)	22°C (72°F)
	Above 50%	300-430 kPa (44-62 psi)	1600-2070 kPa (232-300 psi)	24°C (75°F)
36-41°C (96-105°F)	Below 20%	328-439 kPa (48-64 psi)	1810-2240 kPa (263-325 psi)	25°C (77°F)
	20-40%	337-457 kPa (49-66 psi)	1840-2290 kPa (267-332 psi)	26°C (79°F)
	Above 40%	355-474 kPa (52-69 psi)	1890-2340 kPa (274-340 psi)	27°C (81°F)
42-46°C (106-115°F)	Below 20%	391-491 kPa (57-71 psi)	2130-2500 kPa (309-363 psi)	29°C (84°F)
42-46°C (106-115°F)	Above 20%	397-508 kPa (58-74 psi)	2160-2550 kPa (313-370 psi)	30°C (86°F)
47-49°C (116-120°F)	Below 30%	451-552 kPa (65-80 psi)	2420-2790 kPa (351-405 psi)	33°C (92°F)

A/C System Pressure Zone Classification

A/C Performance Table - 6.6L

Ambient Air Temperature	Relative Humidity	Service Port Pressure		Maximum Discharge Air Temperature
Ambient Air Temperature	Relative Humidity	Low Side	High Side	Maximum Discharge Air Temperature
13-18°C (55-65°F)	0-100%	150-279 kPa (22-41 psi)	420-1140 kPa (61-165 psi)	9°C (48°F)
19-24°C (66-75°F)	Below 40%	150-298 kPa (22-43 psi)	531-1240 kPa (77-180 psi)	11°C (52°F)
19-24°C (66-75°F)	Above 40%	176-366 kPa (26-53 psi)	760-1510 kPa (110-219 psi)	14°C (57°F)
25-29°C (76-85°F)	Below 35%	216-359 kPa (31-52 psi)	990-1550 kPa (143-225 psi)	15°C (59°F)
	35-50%	250-382 kPa (36-55 psi)	1130-1640 kPa (164-238 psi)	16°C (61°F)
	Above 50%	275-430 kPa (40-62 psi)	1230-1820 kPa (178-264 psi)	18°C (64°F)
30-35°C (86-95°F)	Below 30%	287-434 kPa (42-63 psi)	1350-1930 kPa (195-280 psi)	19°C (66°F)
	30-50%	311-463 kPa (45-67 psi)	1440-2040 kPa (209-296 psi)	21°C (70°F)
	Above 50%	342-506 kPa (50-73 psi)	1560-2190 kPa (226-318 psi)	23°C (73°F)
36-41°C (96-105°F)	Below 20%	366-506 kPa (53-73 psi)	1750-2300 kPa (254-334 psi)	23°C (73°F)
	20-40%	382-531 kPa (55-77 psi)	1800-2390 kPa (261-347 psi)	25°C (77°F)
	Above 40%	409-557 kPa (59-81 psi)	1900-2480 kPa (276-360 psi)	27°C (81°F)
42-46°C (106-115°F)	Below 20%	452-575 kPa (66-84 psi)	2180-2660 kPa (316-386 psi)	27°C (81°F)
42-46°C (106-115°F)	Above 20%	465-599 kPa (68-87 psi)	2220-2730 kPa (322-396 psi)	29°C (84°F)
47-49°C (116-120°F)	Below 30%	535-629 kPa (78-91 psi)	2580-2900 kPa (375-421 psi)	30°C (86°F)