GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2003 🢒 Seville 🢒 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

Tools Required

J 43600

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 restricted air flow at the condenser.

    • Inspect between the condenser and the radiator.
    • Inspect for missing or misaligned air baffles.

Is the air flow through the condenser restricted?

Go to Step 4

Go to Step 6

4
  1. Repair the air flow restriction.
  2. Replace the condenser, if damaged. Refer to Condenser Replacement .

Is the repair complete?

Go to Step 6

--

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: 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 on both sides of the expansion device?

Go to Step 7

Go to Step 8

7
  1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging .
  2. 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 refrigerant system, or the system is overcharged. Recover and recharge the A/C system. Refer to Refrigerant Recovery and Recharging .

Is the repair complete?

Go to Step 9

--

9
  1. Take readings of the low and high side pressures as well as the I/P outlet air temperature after repairs are performed.
  2. Compare the pressures and outlet 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 system in order to verify the repair.

Did you find and correct the condition?

System OK

Go to Symptoms - HVAC Systems - Automatic