Chevrolet Silverado / GMC Sierra. Service manual — part 2299

Fig. 1: A/C System Pressure (6.6L)
Courtesy of GENERAL MOTORS CORP.

A/C Performance Table - Diesel Engine

Ambient Air

Temperature

Relative

Humidity

Service Port Pressure

Maximum

Discharge

Air

Temperature

Low Side

High Side

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)

Above 40%

176-366 kPa (26-53

psi)

760-1510 kPa (110-

219 psi)

14°C (57°F)

216-359 kPa (31-52

990-1550 kPa (143-

2008 Chevrolet Silverado 1500

2008 HVAC Heating, Ventilation, and Air Conditioning - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

AIR CONDITIONING (A/C) SYSTEM PERFORMANCE TEST (GAS ENGINE W/ ELECTRIC
COOLING FAN)

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.

25-29°C (76-

85°F)

Below 35%

psi)

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)

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)

2008 Chevrolet Silverado 1500

2008 HVAC Heating, Ventilation, and Air Conditioning - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

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

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

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

Step

Action

Values

Yes

No

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.

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 for
about 2 minutes.

4. Turn OFF the ignition.

5. Install the J 43600 ACR 2000

Refrigerant Station. See Special
Tools.

6. Record the ambient air temperature

displayed on the J 43600 . See
Special Tools.

7. 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

1. Close the vehicle doors and

windows.

IMPORTANT:

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

2008 Chevrolet Silverado 1500

2008 HVAC Heating, Ventilation, and Air Conditioning - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

2

2. Open the drivers door window 127-

152 mm (5-6 inches).

3. 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

4. Install the temperature probes to the

J 43600 in the left and right center
air outlets. See Special Tools.

5. Apply the parking brake.

6. Place the transaxle/transmission in

one of the following positions:

PARK for Automatic

NEUTRAL for Manual

7. Start the engine.

8. Operate the A/C system for 5

minutes.

9. Inspect A/C components for the

following conditions:

Abnormal frost areas

Unusual noises

10. Print the following information:

The panel outlet air
temperatures

IMPORTANT:

Press the RESET button, before using
the print function of the J 43600 . See
Special Tools.

-

2008 Chevrolet Silverado 1500

2008 HVAC Heating, Ventilation, and Air Conditioning - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado