Chevrolet Silverado / GMC Sierra. Service manual — part 2300

The low-side pressure

The high-side pressure

11. 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

3

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

1. Continue to operate the A/C system

for an additional 5 minutes.

2. RESET the J 43600 and record the

pressures and temperatures again.
See Special Tools.

3. 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

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

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

2008 Chevrolet Silverado 1500

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

Silverado

A/C System Pressure Zone Classification - Gas Engine With Electric Cooling Fan or RPO HP2

6

-

(A/C)
Diagnostics -
Pressure
Zone C

Go to Step 7

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

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
Go to
Symptoms -
HVAC
Systems -
Automatic

2008 Chevrolet Silverado 1500

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

Silverado

Fig. 2: A/C System Pressure Zone Classification - Gas Engine With Engine Driven
Cooling Fan
Courtesy of GENERAL MOTORS CORP.

A/C Performance Table - Gas Engine With Electric Cooling Fan or RPO HP2

Ambient Air

Temperature

Relative

Humidity

Service Port Pressure

Maximum

Discharge

Air

Temperature

Low Side

High Side

13-18°C (55-

65°F)

0-100%

165-257 kPa (24-37

psi)

830-1180 kPa (120-

171 psi)

10°C (50°F)

19-24°C (66-

75°F)

Below 40%

185-290 kPa (27-42

psi)

1010-1340 kPa (147-

194 psi)

11°C (52°F)

Above 40%

202-313 kPa (29-45

psi)

990-1370 kPa (144-

199 psi)

13°C (55°F)

Below 35% 225-319 kPa (33-46 1180-1470 kPa (171- 14°C (57°F)

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/ENGINE DRIVE
DRIVEN 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)

psi)

213 psi)

35-50%

238-330 kPa (35-48

psi)

1180-1490 kPa (171-

216 psi)

14°C (57°F)

Above 50%

248-352 kPa (36-51

psi)

1190-1520 kPa (173-

221 psi)

16°C (61°F)

30-35°C (86-

95°F)

Below 30%

257-359 kPa (37-52

psi)

1320-1610 kPa (192-

234 psi)

17°C (63°F)

30-50%

267-375 kPa (39-54

psi)

1340-1650 kPa (194-

239 psi)

18°C (64°F)

Above 50%

281-399 kPa (41-58

psi)

1360-1710 kPa (197-

248 psi)

20°C (68°F)

36-41°C (96-

105°F)

Below 20%

290-393 kPa (42-57

psi)

1480-1760 kPa (215-

255 psi)

19°C (66°F)

20-40%

298-411 kPa (43-60

psi)

1500-1820 kPa (218-

264 psi)

21°C (70°F)

Above 40%

313-429 kPa (45-62

psi)

1540-1880 kPa (224-

273 psi)

22°C (72°F)

42-46°C (106-

115°F)

Below 20%

327-428 kPa (47-62

psi)

1650-1910 kPa (239-

277 psi)

21°C (70°F)

Above 20%

336-448 kPa (49-65

psi)

1680-1980 kPa (244-

287 psi)

23°C (73°F)

47-49°C (116-

120°F)

Below 30%

367-474 kPa (53-69

psi)

1830-2100 kPa (266-

305 psi)

25°C (77°F)

2008 Chevrolet Silverado 1500

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

Silverado