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Performance Test Procedure

WARNING: This page is about a different car, the 2005 Dodge Grand Caravan, 2005 Dodge Caravan, and 2005 Chrysler Town & Country. However, it is still accessible from the selected car via links, so may be relevant.
WARNING: Refer to the applicable warnings and cautions for this system before performing the following operation (Refer to HEATING & AIR CONDITIONING/PLUMBING - FRONT - WARNINGS)  and (Refer to HEATING & AIR CONDITIONING/PLUMBING - FRONT - CAUTIONS) . Failure to follow the warnings and cautions could result in possible personal injury or death.
NOTE: When connecting the service equipment coupling to the line fitting, verify that the valve of the coupling is fully closed. This will reduce the amount of effort required to make the connection.
  1. Connect a tachometer and a manifold gauge set.
  2. Set the mode control to the Recirculation Mode position, the temperature control to the full cool position and the blower to the highest speed position.
  3. Start the engine and hold at 1,000 rpm with the A/C compressor clutch engaged.
  4. The engine should be warmed up to operating temperature with the doors closed and windows open.
  5. Insert a thermometer in the driver's side center panel A/C-heater outlet and operate the engine for five minutes.
  6. If the compressor clutch does not engage, proceed with diagnosis of the compressor clutch coil. (Refer to A/C COMPRESSOR CLUTCH COIL ).
  7. With the A/C compressor clutch engaged, compare the air temperature at the center panel outlet and the compressor discharge pressure to the A/C Performance Temperature and Pressure chart. The compressor clutch may cycle, depending upon the ambient temperature and humidity. If the clutch cycles, use the readings obtained before the clutch disengaged.
    A/C PERFORMANCE TEMPERATURE AND PRESSURE

    Ambient Temperature 

    21° C

    (70° F)

    27° C

    (80° F)

    32° C

    (90° F)

    38° C

    (100° F)

    43° C

    (110° F)
    Left Center Panel Outlet Discharge Air Temperature 

    1 to 8° C

    (34 to 46° F)

    3 to 9° C

    (37 to 49° F)

    4 to 10°C

    (39 to 50° F)

    6 to 11°C

    (43 to 52° F)

    7 to 18° C

    (45 to 65° F)
    Discharge Pressure (High Side Service Port) 

    1034 to 1724 kPa

    (150 to 250 psi)

    1517 to 2275 kPa

    (220 to 330 psi)

    1999 to 2620 kPa

    (290 to 380 psi)

    2068 to 2965 kPa

    (300 to 430 psi)

    2275 to 3421 kPa

    (330 to 450 psi)
    Suction Pressure (Low Side Service Port) 

    103 to 207 kPa

    (15 to 30 psi)

    117 to 221 kPa

    (17 to 32 psi)

    138 to 241 kPa

    (20 to 35 psi)

    172 to 269 kPa

    (25 to 39 psi)

    207 to 345 kPa

    (30 to 50 psi)
  8. If the air outlet temperature fails to meet the specifications in A/C PERFORMANCE TEMPERATURE AND PRESSURE , or if the compressor discharge pressure is high, refer to A/C PRESSURE DIAGNOSIS .
A/C PRESSURE DIAGNOSIS

Condition Possible Causes Correction
Rapid A/C compressor clutch cycling (ten or more cycles per minute).

1. Low refrigerant system charge.

1. See REFRIGERANT SYSTEM LEAKS . Test the refrigerant system for leaks. Repair, evacuate and charge the refrigerant system, if required.
Equal pressures, but the compressor clutch does not engage.

1. No refrigerant in the refrigerant system.

1. See REFRIGERANT SYSTEM LEAKS . Test the refrigerant system for leaks. Repair, evacuate and charge the refrigerant system, if required.

2. Faulty fuse.

2. Check the fuses in the Integrated Power Module. Repair the shorted circuit or component and replace the fuses, if required. Refer to appropriate service information.

3. Faulty A/C compressor clutch coil.

3. See A/C COMPRESSOR CLUTCH COIL . Test the compressor clutch coil and replace, if required.

4. Faulty A/C compressor clutch relay.

4. See A/C COMPRESSOR CLUTCH RELAY . Test the compressor clutch relay and relay circuits. Repair the circuits or replace the relay, if required.

5. Improperly installed or faulty evaporator temperature sensor.

5. See EVAPORATOR TEMPERATURE SENSOR . Test the sensor and replace, if required.

6. Faulty A/C pressure transducer.

6. See A/C Pressure Transducer in this service information. Test the sensor and replace, if required.

7. Faulty Powertrain Control Module (PCM).

7. Refer to POWERTRAIN DIAGNOSTIC PROCEDURES for testing of the PCM. Test the PCM and replace, if required.
Normal pressures, but A/C Performance Test air temperatures at center panel outlet are too high.

1. Excessive refrigerant oil in system.

1. See REFRIGERANT OIL LEVEL . Recover the refrigerant from the refrigerant system and inspect the refrigerant oil content. Restore the refrigerant oil to the proper level, if required.

2. Blend door actuator improperly installed or faulty.

2. See BLEND DOOR ACTUATOR . Inspect the actuator for proper operation and replace, if required.

3. Blend door inoperative or sealing improperly.

3. See HVAC HOUSING . Inspect the blend door for proper operation and sealing. Repair if required.
-

4. Blend door not in full cold position.

 Use a DRBIII Scan Tool to check for DTCs and blend door position. Refer to BODY DIAGNOSTIC PROCEDURES .
The low side pressure is normal or slightly low, and the high side pressure is too low.

1. Low refrigerant system charge.

1. See REFRIGERANT SYSTEM LEAKS . Test the refrigerant system for leaks. Repair, evacuate and charge the refrigerant system, if required.

2. Refrigerant flow through the A/C evaporator is restricted.

2. See A/C EVAPORATOR . Replace the restricted A/C evaporator, if required.

3. Faulty A/C compressor.

3. See A/C Compressor in this article. Replace the compressor, if required.
The low side pressure is normal or slightly high, and the high side pressure is too high.

1. A/C condenser air flow restricted.

1. Check the A/C condenser for damaged fins, foreign objects obstructing air flow through the condenser fins, and missing or improperly installed air seals. Clean, repair, or replace components as required.

2. Refrigerant flow through the receiver/drier is restricted.

2. See RECEIVER / DRIER . Replace the restricted receiver/drier, if required.

3. Inoperative radiator cooling fan.

3. Test the radiator cooling fan and replace, if required. Refer to COOLING .

4. Refrigerant system overcharged.

4. See REFRIGERANT SYSTEM CHARGE . Recover the refrigerant from the refrigerant system. Charge the refrigerant system to the proper level, if required.

5. Air in the refrigerant system.

5. See REFRIGERANT SYSTEM LEAKS . Test the refrigerant system for leaks. Repair, evacuate and charge the refrigerant system, if required.

6. Engine overheating.

6. Test the engine cooling system and repair, if required. Refer to COOLING .
The low side pressure is too high, and the high side pressure is too low.

1. Accessory drive belt slipping.

1. Inspect the accessory drive belt condition and tension. Tighten or replace the accessory drive belt, if required. Refer to COOLING .

2. Faulty A/C expansion valve.

2. See EXPANSION VALVE . Replace the valve, if required.

3. Faulty A/C compressor.

3. See A/C Compressor in this article. Replace the compressor, if required.
The low side pressure is too low, and the high side pressure is too high.

1. Restricted refrigerant flow through the refrigerant lines.

1. See LIQUID LINE , SUCTION LINE  and A/C DISCHARGE LINE . Inspect the refrigerant lines for kinks, tight bends or improper routing. Correct the routing or replace the refrigerant line, if required.

2. Restricted refrigerant flow through the A/C expansion valve.

2. See EXPANSION VALVE . Replace the valve, if required.

3. Restricted refrigerant flow through the A/C condenser.

3. See A/C CONDENSER . Replace the restricted condenser, if required.
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