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

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

Feel the liquid line before the expansion device.

Is the liquid line cold before the expansion device?

Go to Step 3

Go to Step 8

Feel along the surfaces of the following high side components:

Did you detect an abrupt drop in temperature along the surfaces of any of the listed components?

Go to Step 7

Go to Step 4

1. Feel the liquid line at the expansion device location for extreme cold, possibly accompanied by heavy frost.
2. Feel along the liquid line beyond the expansion device location for warm temperature.

Is the liquid line extremely cold at the expansion device location and warm beyond the expansion device location?

Go to Step 11

Go to Step 5

Feel along the surfaces of the following low side components:

Did you feel an abrupt temperature change along the surfaces of any of the listed components?

Go to Step 7

Go to Step 6

Feel along the surfaces of the low and the high side components:

Are all the temperatures of these components only mildly warm?

Go to Step 14

Go to Step 8

1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging.
2. Remove the restriction from the component, or replace the component which produced an abrupt temperature drop.

Is the repair complete?

Go to Step 9

--

1. Recover the refrigerant and evacuate the system. Refer to Refrigerant Recovery and Recharging.
2. Record the weight of the recovered refrigerant.
3. Compare the weight of the recovered refrigerant with the system capacity. Refer to Refrigerant System Capacities.

Is the weight of the recovered refrigerant charge greater than 75 percent of the total system capacity?

Go to Step 9

Go to Step 10

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

Is the cooling performance improved?

Go to Step 18

Go to Step 10

1. Leak test the system. Refer to Leak Testing.
2. Repair any leaks.

Is the repair complete?

Go to Step 9

--

1. Replace the A/C refrigerant filter. Refer to Air Conditioning (AC) Refrigerant Filter Replacement.
2. Replace the expansion device. Refer to Air Conditioning Evaporator Thermal Expansion Valve Replacement.

Are metal flakes present?

Go to Step 12

Go to Step 13

1. Remove the compressor hose assembly from the vehicle. Refer to Air Conditioning Compressor and Condenser Hose Replacement.
2. Inspect the hose for debris by blowing shop air through one end of the hose while covering the other end with a shop towel.
3. Observe the amount of debris collected in the shop towel.

Did a large amount of debris collect in the shop towel?

Go to Step 16

Go to Step 17

If the expansion device was restricted with a brown or black residue, perform the following procedure:

1. Replace the condenser. Refer to Air Conditioning Condenser Replacement.
2. Flush the A/C system. Refer to Flushing.

Are the repairs complete?

Go to Step 18

--

1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging.
2. Disconnect the compressor hose from the compressor. Refer to Air Conditioning Compressor and Condenser Hose Replacement.
3. Inspect for the presence of debris in the compressor suction port.

Is debris present in the compressor suction port?

Go to Step 15

Go to Step 17

1. Remove the debris from the suction port.
2. Inspect the A/C refrigerant filter for damage or debris. Refer to Air Conditioning (AC) Refrigerant Filter Replacement.
3. Inspect the expansion device for damage or debris. Refer to Air Conditioning Evaporator Thermal Expansion Valve Replacement.

Did you find evidence of damage or debris?

Go to Step 11

Go to Step 12

1. Replace the condenser. Refer to Air Conditioning Condenser Replacement.
2. Install a suction screen. Refer to Suction Screen Replacement.

Is the repair complete?

Go to Step 17

--

1. Install the compressor hose assembly. Refer to Air Conditioning Compressor and Condenser Hose Replacement.
2. Recharge the A/C system. Refer to Refrigerant Recovery and Recharging.

Are the repairs complete?

Go to Step 18

--

1. Record the low and the high side pressures and the panel outlet air temperature after you perform the repairs.
2. Compare the pressures and the panel 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 as shown on the A/C Performance Chart?

Go to Step 19

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

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

Go to Symptoms - HVAC Systems - Automatic