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 for Manual Systemor Air Temperature Malfunction for Automatic System

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. If the vehicle history shows multiple A/C repairs and is suspected of improper polyalkylene glycol (PAG) oil balancing in the previous repairs, 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 vehicles A/C repair history.

1. Drain all of the PAG oil drain bottle on the J 43600 ACR 2000.
2. Flush the A/C system. Refer to Flushing .

Was more than the total system capacity of refrigerant oil recovered from the J 43600 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

or

Go to Symptoms - HVAC Systems - Automatic