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

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2002 🢒 GMC C Sierra - 2WD 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Air Conditioning (A/C) System Performance Test

Table 1:

A/C Performance Table

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 .
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 theJ 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 theJ 43600 and record the pressures and temperatures again.
Compare the low and high side pressures and the paneln 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

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%	175-206 kPa (25-30 psi)	340-850 kPa (49-123 psi)	7°C (45°F)
19-24°C (66-75°F)	Below 40%	175-215 kPa (25-31 psi)	430-930 kPa (62-135 psi)	6°C (43°F)
19-24°C (66-75°F)	Above 40%	175-254 kPa (25-37 psi)	570-1070 kPa (83-155 psi)	9°C (48°F)
25-29°C (76-85°F)	Below 35%	175-249 kPa (25-36 psi)	760-1410 kPa (147-205 psi)	9°C (42°F)
	35-60%	175-261 kPa (26-38 psi)	830-1180 kPa (120-171 psi)	10°C (50°F)
	Above 60%	185-286 kPa (27-42 psi)	880-1250 kPa (128-181 psi)	11°C (52°F)
30-35°C (86-95°F)	Below 30%	193-293 kPa (28-43 psi)	1010-1410 kPa (146-205 psi)	12°C (54°F)
	30-50%	228-269 kPa (30-44 psi)	1050-1440 kPa (153-209 psi)	13°C (55°F)
	Above 50%	221-324 kPa (32-47 psi)	1100-1470 kPa (160-213 psi)	14°C (58°F)
36-41°C (96-105°F)	Below 20%	241-337 kPa (35-47 psi)	1310-1700 kPa (190-246 psi)	16°C (61°F)
	20-40%	247-345 kPa (36-50 psi)	1320-1700 kPa (190-230 psi)	16°C (61°F)
	Above 40%	259-353 kPa (37-52 psi)	1350-1690 kPa (196-246 psi)	16°C (61°F)
42-46°C (106-115°F)	Below 20%	292-378 kPa (42-55 psi)	1630-1950 kPa (238-283 psi)	17°C (62°F)
42-46°C (106-115°F)	Above 20%	297-383 kPa (43-55 psi)	1620-1930 kPa (235-280 psi)	19°C (66°F)
47-49°C (116-120°F)	Below 30%	338-405 kPa (50-59 psi)	187-2080 kPa (271-302 psi)	20°C (68°F)