Step
| Action
| Yes
| No
|
DEFINITION: The low side pressure is lower than normal and the high side pressure is higher than normal.
• | A restriction in the Air Conditioning (A/C) system |
|
1
| Were you sent here from the air conditioning (A/C) System Performance Test?
| Go to Step 2
| Go to Air Conditioning (A/C) System Performance Test
|
2
| Feel the liquid line before the thermal expansion valve (TXV).
Is the liquid line cold before the TXV?
| Go to Step 3
| Go to Step 8
|
3
| Feel along the surfaces of the following high side components:
• | The compressor hose between the compressor and the condenser |
• | The liquid line between the condenser and the TXV |
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
|
4
|
- Feel the liquid line at the TXV location for extreme cold, possibly accompanied by heavy frost.
- Feel along the liquid line beyond the TXV location for warm temperature.
Is the liquid line extremely cold at the TXV location and warm beyond the TXV location?
| Go to Step 11
| Go to Step 5
|
5
| Feel along the surfaces of the following low side components:
• | The evaporator inlet tube between the TXV and the evaporator core |
• | The evaporator outlet tube between the evaporator core and the compressor suction hose |
• | The compressor suction hose |
Did you feel an abrupt temperature change along the surfaces of any of the listed components?
| Go to Step 7
| Go to Step 6
|
6
| Feel along the surfaces of the low and the high side components.
• | The evaporator inlet tube between the TXV and the evaporator core |
• | The evaporator outlet hose between the TXV and the compressor |
• | The compressor hose assembly |
• | The liquid line between the condenser and the TXV |
Are the temperatures of these components only mildly warm?
| Go to Step 14
| Go to Step 8
|
7
|
- Recover the refrigerant. Refer to Refrigerant Recovery and Recharging .
- Remove the restriction from the component, or replace the component which produced an abrupt temperature drop.
Is the action complete?
| Go to Step 9
| -
|
8
|
- Recover the refrigerant and evacuate the system. Refer to Refrigerant Recovery and Recharging .
- Record the weight of the recovered refrigerant.
- Compare the weight of the recovered refrigerant with the system capacity. Refer to Refrigerant System Specifications .
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
|
9
| Recharge the A/C system. Refer to Refrigerant Recovery and Recharging .
Is the cooling performance improved?
| Go to Step 20
| Go to Step 10
|
10
|
- Leak test the system. Refer to Leak Testing .
- Repair any leaks.
Is the action complete?
| Go to Step 20
| -
|
11
| The TXV is restricted.
- Replace the TXV. Refer to Air Conditioning Evaporator Thermal Expansion Valve Replacement .
- If the TXV was restricted, note the type of debris present.
Are metal flakes present?
| Go to Step 12
| Go to Step 13
|
12
|
- Remove the compressor hose assembly from the vehicle. Refer to
Air Conditioning Compressor Hose Replacement : Diesel → L4 → V6 .
- Inspect the hose for debris by blowing compressed air through one end of the hose while covering the other end with a workshop cloth.
- Observe the amount of debris collected in the workshop cloth.
Did a large amount of debris collect in the workshop cloth?
| Go to Step 18
| Go to Step 19
|
13
| If the TXV was restricted with a brown or black residue, replace the refrigerant desiccant.
Are the actions complete?
| Go to Step 20
| -
|
14
|
- Recover the refrigerant. Refer to Refrigerant Recovery and Recharging .
- Disconnect the compressor hose from the compressor. Refer to
Air Conditioning Compressor Hose Replacement : Diesel → L4 → V6 .
- Inspect for the presence of debris in the compressor suction port.
Are debris present in the compressor suction port?
| Go to Step 15
| Go to Step 19
|
15
|
- Remove the debris from the suction port.
- Inspect the TXV for damage or debris. Refer to Air Conditioning Evaporator Thermal Expansion Valve Replacement .
Did you find evidence of damage or debris?
| Go to Step 17
| Go to Step 16
|
16
| If the TXV does not show any signs of damage or debris, perform the following procedure:
- Remove the compressor hose assembly from the vehicle. Refer to
Air Conditioning Compressor Hose Replacement : Diesel → L4 → V6 .
- Inspect the hose for debris by blowing compressed air through one end of the hose while covering the other end with a workshop cloth.
- Observe the amount of debris collected in the workshop cloth.
Did a large amount of debris collect in the workshop cloth?
| Go to Step 18
| Go to Step 19
|
17
|
- Replace the TXV. Refer to Air Conditioning Evaporator Thermal Expansion Valve Replacement .
- If the TXV was restricted, observe the type of debris present.
Are metal flakes present?
| Go to Step 12
| Go to Step 13
|
18
| If a large amount of debris was collected in the workshop cloth from the compressor hose assembly, replace the refrigerant desiccant.
Is the action complete?
| Go to Step 19
| -
|
19
|
- Install the compressor hose assembly. Refer to
Air Conditioning Compressor Hose Replacement : Diesel → L4 → V6 .
- Recharge the A/C system. Refer to Refrigerant Recovery and Recharging .
Are the actions complete?
| Go to Step 20
| -
|
20
|
- Record the low and the high side pressures and the instrument panel outlet air temperature after you perform the repairs.
- Compare the pressures and the instrument panel outlet air 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 21
| Go to Air Conditioning (A/C) System Performance Test
|
21
| Operate the system in order to verify the repair.
Did you find and correct the condition?
| System OK
| Go to Symptoms - HVAC Systems - Automatic .
|