DEFINITION: The high and low side pressures may be normal or slightly less than normal.

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

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Go to Step 2

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

Refer to the instrument panel outlet air temperatures recorded during the A/C system performance test.

Does the discharge air temperature between the right and left center instrument panel outlets vary by more than 1-2°C (2-3°F)?

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Go to Step 7

Go to Step 3

Did the customer mention that the A/C system output temperatures are good at first, but then turn warm during extended drives?

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Go to Step 4

Go to Step 5

Increase engine speed to 2000 RPM.

During extended operation of the A/C system, does the low side pressure decrease, possibly accompanied by heavy frost on the liquid line between the expansion device and the evaporator?

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Go to Air Conditioning (A/C) Diagnostics - Pressure Zone D

Go to Step 5

1. Refer to the pressures recorded during the A/C system performance test.

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

2. Inspect for the following conditions:

•	The high side pressure is slightly greater than the specified pressure ranges but still within Zone A on the A/C Pressure-Zone Classification Chart in the A/C System Performance Test. Refer to Air Conditioning (A/C) System Performance Test.

•	The discharge line is hot.

•	The suction line is cool.

Do the listed conditions exist?

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Go to Step 7

Go to Step 6

1. Refer to the pressures recorded during the A/C system performance test.
2. Inspect for the following conditions:

•	The low side pressure is slightly lower than the specified pressure ranges but still within Zone A on the A/C Pressure-Zone Classification Chart in the A/C System Performance Test. Refer to Air Conditioning (A/C) System Performance Test.

•	The discharge line is warm to hot.

•	The suction line is cool to warm.

Do the listed conditions exist?

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Go to Step 8

Go to Diagnostic Starting Point - Heating, Ventilation and Air Conditioning

The A/C system may be undercharged.

1. Leak test A/C system. Refer to Leak Testing.
2. Recharge the A/C system to specifications. Refer to Refrigerant Recovery and Recharging.

Is the action complete?

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Go to Step 13

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The A/C system may be contaminated.

View the information screen on the J 43600 ACR 2000 Air Conditioning Service Center for detection of foreign gases in the A/C system.

Do foreign gases exist?

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Go to Step 9

Go to Step 10

1. Evacuate the A/C system to a scavenging tank. Refer to Refrigerant Recovery and Recharging.
2. Recharge the A/C system to specifications.

Is the action complete?

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Go to Step 13

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The A/C system may contain too much moisture or air.

1. Evacuate and recharge the A/C system to specifications. Refer to Refrigerant Recovery and Recharging.
2. Operate the A/C system and inspect the instrument panel outlet air temperatures. Refer to Air Conditioning (A/C) System Performance Test.

Are the instrument panel outlet air temperatures within the specified ranges of the A/C Performance Test Table?

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Go to Step 14

Go to Step 11

The A/C system may contain too much refrigerant oil.

Important: Review the vehicle's A/C repair history.

If the vehicle history shows multiple A/C repairs and is suspected of improper PAG oil balancing in the previous repairs, perform the following procedure:

1. Drain all of the PAG oil drain bottle on the ACR 2000.
2. Flush the A/C system. Refer to Flushing.

Was more than the total system capacity of refrigerant oil recovered from the ACR 2000 oil drain bottle?

150 ml (5 oz)

Go to Step 12

Go to Step 13

1. Add the specified amount of refrigerant oil. Refer to Refrigerant System Capacities.
2. Recharge the A/C system. Refer to Refrigerant Recovery and Recharging.

Are the actions complete?

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Go to Step 13

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1. Record the low and high side pressures and the instrument panel outlet air temperature.
2. Compare the instrument panel outlet air temperatures to those listed in the A/C System Performance Chart. Refer to Air Conditioning (A/C) System Performance Test.

Are the high and low side pressures and the instrument panel outlet air temperatures within specifications?

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Go to Step 14

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Operate the system in order to verify the repair.

Did you find and correct the condition?

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System OK

Go to Symptoms - HVAC Systems - Manual