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A/C Performance Test

WARNING: This page is about a different car, the 2009 Jeep Patriot and 2009 Jeep Compass. 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. See Heating and Air Conditioning/Plumbing - Warning  and Heating and Air Conditioning/Plumbing - Caution . Failure to follow the warnings and cautions could result in possible serious or fatal injury.
CAUTION: The use of an A/C recycling/charging station for purposes of determining the actual charge level of an A/C system is not recommend. Service recycling/charging stations do not reflect the correct amount of refrigerant charge in the A/C system after a single "reclaim" cycle. Tests have shown that it can take up to 3 or 4 "reclaim" cycles to remove all of the refrigerant charge, depending on the equipment being used. Use only the following procedure for determining the proper charge level.
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. Using a scan tool, check for Diagnostic Trouble Codes (DTCs) in the Powertrain Control Module (PCM) or Engine Control Module (ECM) (depending on engine application), Cabin Compartment Node (CCN), gateway module and the Totally Integrated Power Module (TIPM). If no DTCs are found, go to  2. If any DTCs are found, repair as required, then proceed to  2.
  2. Connect a tachometer and a manifold gauge set or an A/C recycling/charging station.
  3. Operate the heating-A/C system under the following conditions.
    • Engine at idle and operating temperature
    • Doors or windows open
    • Transaxle in Park or Neutral with parking brake set (depending on transaxle application)
    • A/C-heater controls set to Recirculation mode (max-A/C), full cool, panel mode, high blower and A/C on.
    NOTE: This procedure requires the technician to know what the temperature and relative humidity is at the time of the test. This information can be obtained from multiple sources, such as the internet or local news media. When the temperature is above 21°C (70°F), it must be combined with humidity to calculate the apparent ambient air temperature. Use the current ambient temperature and the relative humidity in your location.
  4. Insert a thermometer in the driver side center panel air outlet and operate the vehicle a minimum of ten minutes to allow the thermometer temperature to stabilize.
  5. Compare the air temperature at the center panel outlet and the A/C system pressures to the A/C Performance Temperature and Pressure chart.
    A/C PERFORMANCE TEMPERATURE AND PRESSURE

    Ambient Temperature (Apparent)  21°C (70°F) 27°C (80°F) 32°C (90°F) 38°C (100°F) 43°C (110°F)
    Air Temperature at Center Panel Outlet  6 -15°C (42 - 59°F) 7 -18°C (45 - 64°F) 9 - 21°C (48 - 69°F) 11 - 22°C (52 - 72°F) 13 - 24°C (56 - 75°F)
    A/C High Side Pressure  1034 - 1896 kPa (150 - 275 psi) 1207 - 2068 kPa (175 - 300 psi) 1379 - 2241 kPa (200 - 325 psi) 1551 - 2413 kPa (225 - 350 psi) 1724 - 2241 kPa (250 - 375 psi)
    A/C Low Side Pressure  214 - 365 kPa (31 - 53 psi) 248 - 407 kPa (36 - 59 psi) 283 - 476 kPa (41 - 69 psi) 317 - 483 kPa (46 - 70 psi) 359 - 496 kPa (52 - 72 psi)
  6. If the air outlet temperature or the A/C system pressures are not within specifications, see A/C SYSTEM DIAGNOSIS .
A/C SYSTEM DIAGNOSIS

Condition Possible Causes Correction
Equal refrigerant pressures

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. Inoperative A/C compressor

2. See A/C COMPRESSOR . Test the compressor and replace, if required.

3. Improperly installed or inoperative A/C pressure transducer

4. See TRANSDUCER, A/C PRESSURE . Test the transducer and replace, if required.

4. Inoperative PCM/ECM (depending on engine application), CCN, gateway module or TIPM

4. See the appropriate Electrical Diagnostic Procedures for testing of the PCM/ECM (depending on engine application), CCN, gateway module and TIPM. Test the modules and replace, if required.
Normal refrigerant pressures, but A/C Performance Test air temperatures at center panel outlet are too high

1. Excessive refrigerant oil in system

1. See Heating and Air Conditioning/Plumbing/OIL, Refrigerant - Standard Procedure . Recover the refrigerant from the refrigerant system and inspect the refrigerant oil content. Restore the refrigerant oil to the proper level, if required.

2. Temperature control cable improperly installed or inoperative

2. See Body/Instrument Panel/BEZEL, Instrument Panel - Removal . Inspect the cable for proper operation. Replace the cable as required.

3. Blend door inoperative or sealing improperly

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

4. Blend door not in full cold position

4. See Body/Instrument Panel/BEZEL, Instrument Panel - Removal . Inspect the cable for proper operation. Replace the cable as required.
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 EVAPORATOR, A/C . Replace the restricted A/C evaporator, if required.

3. Inoperative A/C compressor

3. See A/C COMPRESSOR . 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. See CONDENSER, A/C . 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 accumulator is restricted

2. See Accumulator. Replace the restricted accumulator, if required.

3. Inoperative radiator cooling fan

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

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

1. Accessory drive belt slipping

1. See COOLING . Inspect the accessory drive belt condition and tension. Replace the accessory drive belt or tensioner, if required.

2. Inoperative A/C orifice tube

2. See TUBE, A/C ORIFICE . Replace A/C liquid line if required.

3. Inoperative A/C compressor

3. See A/C COMPRESSOR . 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 LINE, A/C LIQUID , LINE, A/C DISCHARGE  and LINE, A/C SUCTION . 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 orifice tube

2. See TUBE, A/C ORIFICE . Replace A/C liquid line if required.

3. Restricted refrigerant flow through the A/C condenser

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