For 1990-2009 cars

#### V5/TXV A/C System Pressure/Temperature 21°C(70°F)

#### V5/TXV A/C System Pressure/Temperature 27°C(80°F)

#### V5/TXV A/C System Pressure/Temperature 32°C(90°F)

#### V5/TXV A/C System Pressure/Temperature 38°C(100°F)

#### V5/TXV A/C System Pressure/Temperature 43°C(110°F)

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Perform the following preliminary tests to the A/C system:

1. Connect the scan tool . Test for diagnostic codes. If you find any codes, refer to Diagnostic Trouble Code (DTC) List (2.4L) or Diagnostic Trouble Code (DTC) List (3.1L).
2. Test and repair the following A/C components as necessary:

• | The A/C fuse

• | The A/C blower operation

• | The A/C compressor clutch coil connection

• | The A/C pressure transducer connection

3. Inspect the temperature door and correct as necessary:

• | Move the temperature door dial rapidly from HOT to COLD.

• | Listen for a change in airflow.

• | Listen for the temperature door hitting at each end.

4. Inspect the A/C compressor belt. Replace the belt if the belt is damaged or missing.
5. Test the condenser for a restricted air flow.
6. Verify that the engine cooling fan is operating in the correct direction, pulling outside air through the condenser toward the engine.

At idle the cooling fan must be ON at any A/C mode, except for vehicles with 3.1L/V6 engines.

7. Refer to the dealer technical bulletins for updates to the A/C system, as needed.
8. Turn on the A/C.

Is the discharge temperature normal?

--

System OK

Go to Step 2

2 |

1. Connect the ACR. Refer to the manufacturer's instructions.
2. Verify that the ambient air temperature is at least 16°C (60°F).
3. Turn the ignition key to the OFF position.
4. Read the high side pressure.

Is the high side pressure greater than the specified value?

413 kPa (60 psi)

Go to Step 6

Go to Step 3

3 |

1. Add 0.45 kg (1 lb) of R-134a.
2. Perform the A/C system leak test . Refer to Leak Testing .

Did you perform the system leak test?

--

Go to Step 4

--

4 |

1. Complete the recovery of the refrigerant according to the instructions from the equipment manufacturer.
2. Repair the leak.

Is the repair complete?

--

Go to Step 5

--

5 | Evacuate and charge the system to system specifications. Did you charge the system? | -- | Go to Step 6 | --
6 |

• | Set the A/C controls to NORMAL.

• | Set the A/C mode to HIGH blower.

• | Set the temperature to full cold.

• | Run the engine at IDLE.

Does the clutch engage?

--

Go to Step 10

Go to Step 7

7 |

1. Turn the ignition switch to OFF.
2. Disconnect the clutch wires at the compressor.
3. Connect a jumper wire from ground to one compressor clutch terminal.
4. Connect a fused jumper wire from the positive battery post to the other compressor clutch terminal.

Does the clutch engage?

--

Go to Step 8

Go to Step 9

8 | Repair the electrical circuit to the compressor clutch. Refer to HVAC Compressor Control Schematics for further diagnostics. Is the repair complete? | -- | Go to Step 10 | --
9 | Replace the clutch coil. Refer to Air Conditioning Clutch Coil Removal . Is the repair complete? | -- | Go to Step 10 | --
10 | Listen carefully for a loud noise, such as a knocking noise from the compressor or a belt-slipping condition. Do you hear an unusual noise? | -- | Go to Step 11 | Go to Step 19
11 | Cycle the compressor ON and OFF in order to verify the source of the noise. Is belt slippage the probable source of the noise? | -- | Go to Step 12 | Go to Step 13
12 | Correct the condition. Refer to Drive Belt Tensioner Diagnosis (2.4L) or Drive Belt Tensioner Diagnosis (3.1L) in Engine Mechanical. Is the noise corrected? | -- | Go to Step 19 | Go to Step 13
13 | The noise probably occurs in the compressor. Does the noise last for longer than 30 seconds? | -- | Go to Step 15 | Go to Step 14
14 | Important: You may observe a liquid slugging condition after an extended system shutdown. This condition occurs at warmer ambient temperatures, followed by an overnight ambient drop. This condition is normal. Is the noise repeatable? | -- | Go to Step 15 | Go to Step 19
15 | The noise condition may be caused by a low charge or by a stuck closed TXV. Test the system performance in order to confirm this diagnosis. Did you test the system performance? | -- | Go to Step 16 | Go to Step 19
16 | The pressures are normal. Inspect the compressor for loose bolts or for hard contact of the A/C plumbing. Repair as needed. Is the system OK? | -- | Go to Step 17 | --
17 | Recover the refrigerant and replace the compressor. Did you replace the compressor? | -- | Go to Step 18 | --
18 | Recharge the system. Did you recharge the system? | -- | Go to Step 19 | --
19 | Important: This test was designed for typical garage conditions:

• | 21-43°C (70-110°F)

• | Various humidities

• | No sun load

Follow this test procedure exactly. This procedure creates a low cooling load in order to cause the V5 compressor to operate at less than full stroke. This is absolutely necessary for accurate test results.

Use the following steps in order to prepare the vehicle for the procedure:

• | Neutralize the internal vehicle temperature to the garage ambient conditions.

• | Lift the hood.

• | Open the windows.

• | Set the temperature lever at full cold.

• | Set the A/C mode to NORMAL.

• | Set the blower motor to HIGH.

1. Set the engine at idle.

Important: The V6 engine cooling fan only operates when the high side pressure exceeds 1 309 kPa (190 psi) or 106°C (223°F) coolant temperature.

2. Turn the engine cooling fan to ON.
3. Refer to HVAC Blower Control Schematics for correct fan operation before proceeding.

Does the fan operate correctly during all A/C modes?

--

Go to Step 21

Go to Step 20

20 | Refer to HVAC Blower Controls System Check for cooling fan diagnostics and correct the fan operation. Is the repair complete? | -- | Go to Step 19 | --
21 |

1. Open the windows.
2. Set the temperature lever at full cold.
3. Set the A/C mode to NORMAL.
4. Set the blower motor to HIGH.
5. Run the engine at idle for 3 minutes.
6. After the A/C system has been operating for 3 minutes, record the following statistics:

• | The low side pressure

• | The high side pressure

• | The center A/C outlet duct temperature

Have you recorded the temperature and the pressures?

--

Go to Step 22

--

22 | Determine if the following conditions exist:

• | The low side pressure and the high side pressure are higher than normal.

• | The compressor cycles off due to a side pressure that is higher than the specified value.

Do the above conditions exist?

2 928 kPa (425 psi)

Go to Step 23

Go to Step 24

23 | The compressor may re-engage later and then cycle OFF again. A high charge may cause this condition. If the charge is high, complete the recovery according to the equipment manufacturer's instructions. Evacuate and charge to system specifications.

Is the repair complete?

--

System OK

--

24 | Determine if the temperature drops abruptly in one of the following areas:

• | The high side plumbing

• | The condensor

| The receiver/dryer

Does the temperature drop in one of the above areas?

--

Go to Step 25

Go to Step 26

25 | The high side should be warm or hot all the way to the TXV. This heat results from the compressor discharge. A high side restriction may be the cause of the condition. Replace the component where the restriction is occurring. Is the repair complete? | -- | System OK | --
26 | Determine if the following conditions exist:

• | The system warms temporarily on extended drives.

• | The system corrects itself after vehicle shut-down.

• | A large puddle of water appears under the vehicle.

Does the system operate correctly except for the above conditions?

--

Go to Step 42

--

27 |

1. Refer to the above chart that corresponds to the current ambient temperature:

• | V5/ TXV A/C System Pressure/Temperature 21°C(70°F)

• | V5/TCV A/C System Pressure/Temperature 27°C(80°F)

• | V5/TCV A/C System Pressure/Temperature 32°C(90°F)

• | V5/TCV A/C System Pressure/Temperature 38°C(100°F]

• | V5/TCV A/C System Pressure/Temperature 43°C(110°F)

2. Read the high side pressure and the low side pressure, and observe the numerically coded area in which the two pressures intersect.

Do the high side pressure and the low side pressure intersect in area 1?

--

Go to Step 36

Go to Step 28

28 | Do the high side pressure and the low side pressure intersect in area 2? | -- | Go to Step 29 | Go to Step 30
29 | The high side pressure and the low side pressure equalize quickly upon turning the A/C OFF. This condition may also be accompanied by a slugging noise during vehicle start-up.

• | Determine if the TXV is stuck open.

• | If the TXV is stuck open, replace the TXV.

Is the repair complete?

--

System OK

--

30 | Do the high side pressure and the low side pressure intersect in area 3? | -- | Go to Step 31 | Go to Step 32
31 | Important: You may discover that the outlet temperature is approximately 11°C (20°F) less than the outside air temperature. This condition is normal. The pressures are normal. Did you perform this test as part of a noise consideration to confirm a possible low charge or a stuck closed TXV? | -- | Go to Step 16 | System OK
32 | Do the high side pressure and the low side pressure intersect in area 4? | -- | Go to Step 33 | --
33 | Important:

• | You may hear a noise like a motorboat inside the vehicle when the following conditions exist:

- | The windows are closed.

- | The blower motor is operating at LOW speed.

• | You may notice a rapid fluctuation of the low side gauge.

Evacuate the system and weigh the charge.

Is the weight of the charge less than the specified value, and did the low side gauge remain steady?

0.8 kg (1.75 lb)

Go to Step 34

Go to Step 35

34 | Recharge the system to specifications. Did you recharge the system? | -- | System OK | --
35 | The charge removed is within specifications and you noticed a rapid fluctuation of the low side gauge. Replace the TXV. Is the repair complete? | -- | System OK | --
36 | A destroked compressor or a no-pump compressor may be the cause of the condition. You may have already tested for this condition and made tentative repairs. Have you already performed a control valve diagnosis? | -- | Go to Step 47 | Go to Step 37
37 |

1. Lower the hood.
2. Set the A/C mode to NORMAL.
3. Set the blower motor to HIGH.
4. Set the temperature lever at full cold.
5. Open the windows and the doors of the vehicle.
6. Run the engine at 3,000 RPM.
7. Cycle the mode lever from VENT to A/C every 20 seconds for 3 minutes

Is the difference between the high side pressure and the low side pressure within the specified value?

207 kPa (30 psi)

Go to Step 38

Go to Step 19

38 | Determine whether the compressor is broken internally:

• | With the engine running, the clutch engages but the high side pressure and the low side pressure remain equal.

• | With the engine OFF and the clutch disengaged, the compressor clutch driver (NOT the pulley) freewheels when rotated by hand.

Is the compressor broken?

--

Go to Step 39

Go to Step 42

39 | Replace the compressor. Is the repair complete? | -- | Go to Step 40 | --
40 | Recover the refrigerant. Evacuate and charge the system according to the equipment manufacturer's instructions. Did you recharge the system? | -- | Go to Step 41 | --
41 | Perform the leak test. Refer to Leak Testing . Did you perform the leak test? | -- | Go to Step 19 | --
42 | Important: Follow this test procedure exactly. This procedure creates a low cooling load in order to cause the V5 compressor to operate at less than full stroke. This is absolutely necessary for accurate test results.

1. A freeze-up in the evaporator core may be the cause of the condition. Confirm that the compressor control valve has failed low.
2. Disconnect the blower motor.
3. Set the A/C mode to MAX.
4. Open the hood.
5. Close the windows and the doors.
6. Start the engine.
7. Run the engine at fast idle speed.

Is the low side pressure within the range specified?

161-238 kPa (23-35 psi)

Go to Step 47

Go to Step 43

43 | Recover the refrigerant according to the equipment manufacturer's instructions. Did you recover the refrigerant? | -- | Go to Step 44 | --
44 | Replace the control valve. Did you replace the control valve? | -- | Go to Step 45 | --
45 | Evacuate and charge the system according to the manufacturer's instructions. Did you charge the system? | -- | Go to Step 46 | --
46 | Perform the leak test. Refer to Leak Testing . Did you perform the leak test? | -- | Go to Step 47 | --
47 | The system should now function normally. Test the system performance again in order to confirm this diagnosis. Did you test the system performance a second time? | -- | Go to Step 48 | Go to Step 19
48 | Do the high side pressure and the low side pressure again intersect in area 1? | -- | Go to Step 49 | System OK
49 | Replace the compressor. Is the repair complete? | -- | System OK | --