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A/C Performance Test

WARNING: This page is about a different car, the 2017 Jeep Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
WARNING:

Review the warnings and cautions for this system before performing the procedure. Failure to follow these instructions may result in serious injury or death.

  1. Make sure the following conditions are met in the area where this test is to be performed:
    • Maximum ambient temperature: 43.3°C (110°F)
    • Minimum ambient temperature: 15.5°C (60°F)
    • Maximum relative humidity: 90%
    • Minimum relative humidity: 20%
  2. Using a scan tool, check for Diagnostic Trouble Codes (DTCs) related to the Controller Area Network (CAN) data bus, HVAC module, Body Control Module (BCM) and Powertrain Control Module (PCM). If no DTCs are found, go to Step 3. If any DTCs are found, repair as required, then proceed to Step 3.
  3. Operate the heating and A/C system under the following conditions.
    • Engine at normal operating temperature
    • Engine at normal idle speed
    • No sun-load in the cabin of the vehicle
    • Vehicle doors and windows closed
    • Transmission in Park or Neutral with the park brake ON.
    • A/C heater controls set to Recirculation mode, full cool, panel mode, high blower and with A/C compressor engaged. If the A/C compressor does not engage, see the A/C System Diagnosis table
    • All panel outlet vanes open and positioned straight rearward
    NOTE:

    If the following step is not performed, the results of this test will not be accurate.

  4. Using a scan tool, operate the engine cooling fans at high speed from the PCM View>Actuators.
  5. Insert a thermometer in the driver side center panel air outlet and operate the A/C system until the thermometer temperature stabilizes or a minimum of five minutes.
    NOTE:

    This procedure requires you to know what the temperature and relative humidity is in your location at the time of the test.

  6. With the A/C clutch engaged, compare the observed panel outlet air temperature along with the ambient temperature of the work area and the relative humidity to the Maximum Panel Outlet Temperature chart.
    A/C PERFORMANCE TEMPERATURE AND PRESSURE

    Ambient Air Temperature (Apparent) 21°C
    (70°F)    		 27°C
    (80°F)    		 32°C
    (90°F)    		 38°C
    (100°F)    		 43°C
    (110°F)
    Maximum Allowable Air Temperature at Center Panel Outlet  9°C
    (48°F)    		 9°C
    (48°F)    		 12°C
    (54°F)    		 15°C
    (59°F)    		 18°C
    (65°F)
    Suction Pressure at Service Port (Low Side)  138 to 207 kPa
    (20 to 30 psi)    		 138 to 207 kPa
    (20 to 30 psi)    		 207 to 276 kPa
    (30 to 40 psi)    		 207 to 276 kPa
    (30 to 40 psi)    		 241 to 310 kPa
    (35 to 45 psi)
    Discharge Pressure at Service Port (High Side)  1034 to 1724 kPa
    (150 to 250 psi)    		 1379 to 2068 kPa
    (200 to 300 psi)    		 1551 to 2241 kPa
    (225 to 325 psi)    		 1724 to 2413 kPa
    (250 to 350 psi)    		 2068 to 2758 kPa
    (300 to 400 psi)
  7. If the air outlet temperature fails to meet the specifications shown in the Maximum Panel Outlet Temperature chart, see the A/C System Diagnosis table.
GC0144949Courtesy of CHRYSLER GROUP, LLC
A/C SYSTEM DIAGNOSIS

Condition Possible Causes Correction
Rapid A/C clutch cycling (ten or more cycles per minute). 1. Low refrigerant system charge. 1. See Refrigerant System Leaks . Refer to PLUMBING, DIAGNOSIS AND TESTING . Test the refrigerant system for leaks. Repair, evacuate and charge the refrigerant system, if required.
Equal pressures, but the A/C clutch does not engage. 1. No refrigerant in the refrigerant system. 1. See Refrigerant System Leaks . Refer to PLUMBING, DIAGNOSIS AND TESTING . Test the refrigerant system for leaks. Repair, evacuate and charge the refrigerant system, if required.
  2. Open fuse. 2. See Wiring Information. Check the fuses in the Power Distribution Center (PDC). Repair the shorted circuit or component and replace the fuse(s), if required.
  3. Inoperative A/C clutch. 3. See A/C Compressor . Test the A/C clutch and coil and replace, if required. Refer to A/C CLUTCH COIL .
  4. Improperly installed or inoperative evaporator temperature sensor. 4. See Evaporator Temperature Sensor . Test the sensor and replace, if required. Refer to SENSOR, EVAPORATOR TEMPERATURE .
  5. Inoperative A/C pressure transducer. 5. See A/C Pressure Transducer . Test the sensor and replace, if required. Refer to TRANSDUCER, A/C PRESSURE 
  6. Inoperative control module, CAN bus or wiring. 6. See the appropriate Electrical Diagnostic Procedures for testing of the modules and CAN bus, and see Wiring Information for compressor control circuit repair, 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. Refer to STANDARD PROCEDURE - REFRIGERANT OIL LEVEL .
  2. Blend door actuator(s) improperly installed or inoperative. 2. See Blend Door Actuator . Inspect the actuator(s) for proper operation and replace, if required. Refer to ACTUATOR, BLEND DOOR .
  3. Blend-air door(s) inoperative or sealing improperly. 3. See HVAC Housing . Inspect the blend-air door(s) for proper operation and sealing. Repair if required. Refer to HOUSING, HVAC .
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. Refer to DIAGNOSIS AND TESTING - 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. Refer to EVAPORATOR, A/C .
  3. Inoperative A/C compressor. 3. See A/C Compressor . Replace the A/C compressor, if required. Refer to COMPRESSOR, A/C .
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 A/C Condenser . 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. Refer to CONDENSER, A/C .
  2. Refrigerant flow through the A/C receiver/drier is restricted. 2. See A/C Receiver/Drier . Replace the restricted A/C receiver/drier, if required. Refer to DRIER, A/C RECEIVER .
  3. Inoperative radiator cooling fan. 3. See Cooling. Test the radiator cooling fan and replace, if required. Refer to ENGINE COOLING SYSTEM .
  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. Refer to REFRIGERANT .
  5. Air in the refrigerant system. 5. See Refrigerant System Leaks in this group. Refer to PLUMBING, DIAGNOSIS AND TESTING . 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. Refer to ENGINE COOLING SYSTEM OVERHEATING .
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. Repair as required. Refer to DIAGNOSIS AND TESTING - SERPENTINE BELT .
  2. Inoperative A/C expansion valve. 2. See A/C Expansion Valve . Replace the valve, if required. Refer to DIAGNOSIS AND TESTING - A/C EXPANSION VALVE .
  3. Inoperative A/C compressor. 3. See A/C Compressor . Replace the A/C compressor, if required. Refer to COMPRESSOR, A/C .
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 Discharge Line . Inspect the refrigerant lines for kinks, tight bends or improper routing. Correct the routing or replace the refrigerant line, if required. Refer to LINE, A/C LIQUID  or LINE, A/C SUCTION  or LINE, A/C DISCHARGE .
  2. Restricted refrigerant flow through the A/C expansion valve. 2. See A/C Expansion Valve . Replace the valve, if required. Refer to DIAGNOSIS AND TESTING - A/C EXPANSION VALVE .
  3. Restricted refrigerant flow through the A/C condenser. 3. See A/C Condenser . Replace the restricted A/C condenser, if required. Refer to CONDENSER, A/C .
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