Chevrolet Silverado / GMC Sierra. Service manual — part 2301

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

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 Engine Driven Cooling Fan

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