GM Service Manual Online
For 1990-2009 cars only

A/C System Pressure -- Zone Classification


Object Number: 466373  Size: MF

Step

Action

Value(s)

Yes

No

1

Were you sent here from the Cooling Insufficient, A/C System diagnostic table?

--

Go to Step 2

Go to Cooling Insufficient - Air Conditioning (A/C) System

2

Visually inspect for restricted air flow at the condenser.

Is the air flow through the condenser restricted

--

Go to Step 3

Go to Step 4

3

  1. Repair the condition (air flow restriction) or replace the condenser, if damaged.
  2. If replacement of the condenser is necessary, recover the refrigerant, then refer to Condenser Replacement
  3. Evacuate and charge the refrigerant system.
  4. Leak test the refrigerant system. Refer to Leak Testing .

Is the repair complete?

--

Go to Step 4

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4

  1. Start the engine and allow the engine to idle.
  2. Turn ON the A/C, using the A/C button.
  3. Inspect for proper cooling fan operation. Refer to Engine Cooling Fan Description - Electric in Engine Controls.

Are the cooling fans ON and operating properly?

--

Go to Step 6

Go to Step 5

5

Repair the cooling fan operation fault. Refer to Engine Oil Level Sensor and/or Switch Diagnosis in Engine Controls.

Is the repair complete?

--

Go to Step 9

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6

  1. The engine still idling in PARK.
  2. The A/C still turned ON.
  3. Feel the liquid line on both sides of the expansion (orifice) tube.

Is the temperature the same before and after the orifice?

--

Go to Step 7

Go to Step 8

7

  1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging .
  2. Replace the damaged/faulty expansion (orifice) tube (orifice opening too large and/or the O-ring is damaged or missing). 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

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9

Take readings of the low and high side pressures as well as the dash outlet air temperature after repairs are performed.

Compair the pressures and outlet temperature to those listed in the A/C Performance Chart.

Are the readings within the specified ranges ?

--

Got to Step 10

Go to Cooling Insufficient - Air Conditioning (A/C) System

10

Operate the system in order to verify the repair.

Did you correct the condition ?

--

System OK

Go to Symptoms in HVAC System - Manual