GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2003 🢒 Century 🢒 HVAC 🢒 Heating, Ventilation and Air Conditioning 🢒 Air Conditioning (A/C) Diagnostics - Pressure Zone C

Step

Action

Yes

No

DEFINITION: The low and the high side pressures are both higher than normal.

    • Restricted Condenser Air Flow
    • Cooling Fan Malfunction
    • Expansion Device Malfunction

1

Were you sent here from the A/C System Performance Test?

Go to Step 2

Go to Air Conditioning (A/C) System Performance Test

2
  1. With the engine idling, turn ON the A/C.
  2. Inspect for proper cooling fan operation. Refer to Cooling System Description and Operation in Engine Cooling.

Are the cooling fans ON and operating properly?

Go to Step 3

Go to Step 5

3

Visually inspect for the following:

    • Restricted airflow
    • Damaged condenser cooling fins
    • Inspect for missing or misaligned air baffles

Do the following conditions exist?

Go to Step 4

Go to Step 6

4

Repair the air flow restriction.

Is the repair complete?

Go to Step 9

--

5

Repair the cooling fan operation fault. Refer to Cooling Fan Inoperative in Engine Cooling.

Is the repair complete?

Go to Step 9

--

6

Caution: Refer to Moving Parts and Hot Surfaces Caution in the Preface section.

Feel the liquid line on both sides of the expansion device.

Is the temperature the same before and after the expansion device?

Go to Step 7

Go to Step 8

7

Replace the damaged/faulty orifice tube. Refer to Expansion (Orifice) Tube Replacement .

Is the repair complete?

Go to Step 9

--

8

Air is in the A/C refrigerant system, or the A/C system is overcharged. Refer to the view screen on the J 43600 ACR 2000 Air Conditioning Center for foreign gas content in the A/C refrigerant.

Recover and recharge the A/C system. Refer to Refrigerant Recovery and Recharging .

Is the repair complete?

Go to Step 9

--

9
  1. Record the low and high side pressures and the instrument panel (I/P) outlet air temperature after repairs are performed.
  2. Compare the pressures and the I/P panel outlet air temperature to those listed in the A/C Performance Chart. Refer to Air Conditioning (A/C) System Performance Test .

Are the readings within the specified ranges?

Go to Step 10

Go to Air Conditioning (A/C) System Performance Test

10

Operate the A/C system in order to verify the repair.

Did you find and correct the condition?

System OK

Go to Symptoms - HVAC Systems - Manual in HVAC Systems-Manual

or

Symptoms - HVAC Systems - Automatic in HVAC Systems-Automatic