DEFINITION: The low side pressure is higher than normal and the high side pressure is lower than normal.

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

Go to Step 2

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

After continued operation of the A/C system, do the low and the high side pressures equalize or become static?

Go to Step 5

Go to Step 3

1. Refer to the pressures recorded during the A/C System Performance Test.
2. Inspect for the following conditions:

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

•	The low side pressure is equal to or greater than the specified pressure range of the A/C Performance Table. Refer to Air Conditioning (A/C) System Performance Test .

•	The high side pressure is less than the specified pressure range of the A/C Performance Table. Refer to Air Conditioning (A/C) System Performance Test .

•	The low side refrigerant line at the compressor feels cool-to-warm.

•	The high side refrigerant line at the compressor feels warm-to-hot.

Do the listed conditions exist?

Go to Step 5

Go to Step 4

1. Refer to the pressures recorded during the A/C System Performance Test.
2. Inspect for the following conditions:

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

•	The low side pressure is greater than the specified pressure range of the A/C Performance Table. Refer to Air Conditioning (A/C) System Performance Test .

•	The high side pressure is less than the specified pressure range of the A/C Performance Table. Refer to Air Conditioning (A/C) System Performance Test .

•	The low side refrigerant line at the compressor feels warm.

•	The high side refrigerant line at the compressor feels warm-to-hot.

Do the listed conditions exist?

Go to Step 5

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

The A/C system has a low refrigerant charge.

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

Is the action complete?

Go to Step 6

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1. After you perform the repairs, record the following:

•	The low and the high side pressures

•	The instrument panel outlet air temperature

2. Compare the pressures and the 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 found on the A/C Performance Chart?

Go to Step 13

Go to Step 7

The A/C compressor is malfunctioning.

Remove the expansion device and inspect for contamination. Refer to Thermal Expansion Valve Replacement .

Did you find metal flakes on the expansion device?

Go to Step 9

Go to Step 8

Inspect the expansion device for a brown, powdery residue indicating desiccant in the A/C system.

Is a brown, powdery residue present?

Go to Step 11

Go to Step 12

1. Remove the compressor hose from the compressor. Refer to Compressor Hose Assembly Replacement .
2. Inspect for metal flake contamination at the line connections and the compressor ports.

Is metal flake contamination present?

Go to Step 10

Go to Step 12

1. Replace the A/C compressor. Refer to Air Conditioning Compressor Replacement .
2. Replace the thermal expansion valve. Refer to Thermal Expansion Valve Replacement .
3. Replace the A/C refrigerant filter. Refer to Air Conditioning (AC) Refrigerant Filter Replacement .
4. Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging .

Is the action complete?

Go to Step 13

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1. Flush the A/C system. Refer to Flushing .
2. Replace the thermal expansion valve. Refer to Thermal Expansion Valve Replacement .
3. Replace the A/C compressor. Refer to Air Conditioning Compressor Replacement .
4. Replace the A/C refrigerant filter. Refer to Air Conditioning (AC) Refrigerant Filter Replacement .
5. Replace the condense. Refer to Condenser Replacement .
6. Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging .

Is the action complete?

Go to Step 13

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1. Replace the A/C compressor. Refer to Air Conditioning Compressor Replacement .
2. Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging .

Is the action complete?

Go to Step 13

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Operate the system in order to verify the repair

Did you find and correct the condition?

System OK

Go to Symptoms - HVAC Systems - Manual

or

Symptoms - HVAC Systems - Automatic