For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
DEFINITION: The low side pressure is higher than normal and the high side pressure is lower than normal.

• | Malfunctioning A/C Compressor

• | Refrigerant Under Charge

1 | Were you sent here from the A/C System Performance Test? | Go to Step 2 | Go to Air Conditioning (A/C) System Performance Test
2 | 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
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

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

5 | 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 | --
6 |

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

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
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
9 |

1. Remove the suction and the discharge lines from the compressor. Refer to Suction Hose Replacement and to Discharge Hose 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

10 |

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

Is the action complete?

Go to Step 13

--

11 |

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 receiver dehydrator. Refer to Receiver Dehydrator Replacement .
5. Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging .

Is the action complete?

Go to Step 13

--

12 |

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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13 | Operate the system in order to verify the repair Did you find and correct the condition? | System OK | Go to Symptoms - HVAC Systems - Manual