GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2005 🢒 Park Avenue 🢒 HVAC 🢒 Heating, Ventilation and Air Conditioning 🢒 Air Conditioning (A/C) Diagnostics - Pressure Zone C

Step

Action

Yes

No

DEFINITION: The low and 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 air conditioning (A/C) System Performance Test?

Go to Step 2

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

2
  1. Start the engine.
  2. Turn ON the A/C.
  3. 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:

    • Damaged condenser cooling fins
    • Missing or misaligned air baffles
    • Restricted air flow

Do any of these conditions exist?

Go to Step 4

Go to Step 6

4

Repair the air flow restriction.

Is the action complete?

Go to Step 9

--

5

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

Is the action complete?

Go to Step 9

--

6

Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury.

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 or faulty expansion tube. Refer to Expansion (Orifice) Tube Replacement .

Is the action complete?

Go to Step 9

--

8
  1. Air is in the refrigerant system, or the system is overcharged. Refer to the view screen on the J 43600 ACR 2000 Air Conditioning Service Center for foreign gas content in the refrigerant.
  2. Recover and recharge the A/C system. Refer to Refrigerant Recovery and Recharging .

Is the action complete?

Go to Step 9

--

9
  1. Record the low and high side pressures and the instrument panel (I/P) outlet air temperature after you have performed the repairs.
  2. Compare the pressures and I/P 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 listed in the A/C Performance Chart?

Go to Step 10

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

10

Operate the system in order to verify the repair.

Did you find and correct the condition?

System OK

Go to Symptoms - HVAC Systems - Automatic in HVAC Systems - Automatic