Performance Test

The performance test will help determine if the A/C system is operating within specifications

1. Do the A/C system inspection (see A/C SYSTEM INSPECTION ), and correct any problems found
2. Connect an R-134a refrigerant recovery/recycling/charging station to the high-pressure service port and the low-pressure service port, following the equipment manufacturer's instructions
3. Determine the relative humidity and air temperature
4. Remove the glove box (see GLOVE BOX REMOVAL/INSTALLATION )
5. Insert a thermometer (A) in the center vent
   Fig 1: Identifying Thermometer In Center Vent

   Courtesy of AMERICAN HONDA MOTOR CO., INC.
6. Place a thermometer (B) near the blower unit's recirculation inlet duct
7. Test conditions
   • Move the vehicle out of direct sunlight and let it cool down to the surrounding (ambient) temperature If necessary, wash the vehicle to cool it down more quickly
   • The ambient temperature must be at least 60 °F (16 °C)
   • Open the hood
   • Open the front doors
   • Set the temperature control button to Max Cool, the mode control button to Vent, and the recirculation control button to Recirculate
   • Turn the A/C button ON and the fan ON/OFF button to Max
   • Hold the engine speed at 1,500 rpm
   • No driver or passengers in the vehicle
8. Inspect the A/C components for the following conditions
   • A/C compressor clutch not engaged
   • Abnormal frost areas
   • Unusual noises

   If you observe any of these conditions, refer to the SYMPTOM TROUBLESHOOTING INDEX 

9. After running the air conditioning for 10 minutes under the above test conditions, read the delivery temperature from the thermometer in the center vent, the intake temperature near the blower unit, and the discharge (high) and suction (low) pressures on the A/C gauges
10. To complete the vent (delivery)/ambient air (intake) temperature chart
    • Mark the vent (delivery) temperature on the vertical line
    • Mark the ambient air (intake) temperature on the bottom line
    • Draw a vertical line from the ambient air (intake) temperature mark
    • Draw a horizontal line from the vent (delivery) temperature mark until it intersects the vertical line
    NOTE: The vent temperature and ambient air temperature should intersect in the shaded area Any measurements outside the area may indicate the need for further inspection
    Fig 2: Vent (Delivery)/Ambient Air (Intake) Temperature Chart

    Courtesy of AMERICAN HONDA MOTOR CO., INC.
11. To complete the high side (discharge) pressure/ambient air (intake) temperature chart
    • Mark the high side (discharge) pressure on the vertical line
    • Mark the ambient air (intake) temperature on the bottom line
    • Draw a vertical line from the ambient air (intake) temperature mark
    • Draw a horizontal line from the high side (discharge) pressure mark until it intersects the vertical line
    NOTE: The high side pressure and ambient air temperature should intersect in the shaded area Any measurements outside the area may indicate the need for further inspection
    Fig 3: High Side (Discharge) Pressure/Ambient Air (Intake) Temperature Chart

    Courtesy of AMERICAN HONDA MOTOR CO., INC.
12. To complete the low side (suction) pressure/ambient air (intake) temperature chart
    • Mark the low side (suction) pressure along the vertical line
    • Mark the ambient air (intake) temperature along the bottom line
    • Draw a vertical line from the ambient air (intake) temperature mark
    • Draw a horizontal line from the low side (suction) pressure mark until it intersects the vertical line
    NOTE: The low side pressure and ambient air temperature should intersect in the shaded area Any measurements outside the area may indicate the need for further inspection
    Fig 4: Low Side (Suction) Pressure/Ambient Air (Intake) Temperature Chart

    Courtesy of AMERICAN HONDA MOTOR CO., INC.
    SYMPTOMS REFERENCE
    
    

    Test results	Related symptoms	Probable cause	Remedy
    Suction and discharge pressures are normal	Warm air from the vents	The A/C system contains too much refrigerant oil The air mix door is not operating properly	Evacuate the system (see SYSTEM EVACUATION ) Adjust the oil level (see A/C SERVICE TIPS AND PRECAUTIONS ), then recharge the system (see SYSTEM CHARGING ) Check air mix door operation, driver's (see DRIVER'S AIR MIX CONTROL MOTOR TEST ), passenger's (see DRIVER'S AIR MIX CONTROL MOTOR REPLACEMENT ), and repair as needed
    Suction and discharge pressures are roughly equal and steady	The suction and discharge pressures equalize when the engine is revved	The A/C compressor clutch or the drive belt is slipping, or the compressor shaft seal is leaking	If the drive belt is slipping, replace the drive belt (see DRIVE BELT REPLACEMENT ) Also inspect the drive belt auto-tensioner (see DRIVE BELT AUTO-TENSIONER REPLACEMENT ) If the A/C compressor clutch is slipping, replace it (see A/C COMPRESSOR CLUTCH OVERHAUL ) Check the A/C compressor shaft seal If it's leaking, replace the A/C compressor (see A/C COMPRESSOR REPLACEMENT )
    Suction and discharge pressures are roughly equal but fluctuate	Suction and discharge pressures fluctuate during operation, and equalize when the compressor clutch disengages	The compressor discharge valve or the compressor gasket is faulty	Replace the A/C compressor (see A/C COMPRESSOR REPLACEMENT )
    Suction and discharge pressures are roughly equal and abnormally low	The suction and discharge pressures do not change during continued operation	The A/C system is undercharged	Do the refrigerant leak check (see REFRIGERANT LEAK CHECK ) Repair any leaks, then recharge the system (see SYSTEM CHARGING )
    Suction and discharge pressures are abnormally high, but normalize when the condenser is cooled	The suction pressure decreases when cool water is sprayed on the A/C condenser	The A/C system is overcharged	Evacuate the A/C system (see SYSTEM EVACUATION ), and recharge it to specifications (see SYSTEM CHARGING )
    Suction and discharge pressures are abnormally high, and refrigerant line temperatures are abnormal	The vapor line to the condenser is too hot The liquid line from the expansion valve is not cold There is an abrupt temperature change in the system	The A/C system refrigerant flow is restricted	Replace the restricted line or component
    The suction pressure is low, the discharge pressure is high, and the refrigerant temperature changes abnormally somewhere in the system	The high pressure liquid line going into the expansion valve is cold There is an abrupt temperature drop in an A/C line or hose	The A/C system refrigerant flow is restricted	Replace the restricted line or component
    Discharge pressure is so high that the compressor relief valve has opened Suction pressure is normal or below normal	The temperature drop between the condenser inlet and outlet is less than 30 °F (16 °C) or more than 60 °F (32 °C)	The A/C condenser or receiver/dryer is restricted	Replace the restricted component, the condenser (see A/C COMPRESSOR RELIEF VALVE REPLACEMENT ) or the receiver/dryer (see RECEIVER/DRYER DESICCANT REPLACEMENT )
    Discharge pressure is so high that the compressor relief valve has opened Suction pressure is also above normal	No evidence of restricted refrigerant flow The A/C compressor clutch stays engaged with the A/C switch off	The A/C compressor clutch circuit is always on (energized), or the compressor clutch is mechanically lammed	Do the A/C compressor clutch circuit troubleshooting (see A/C COMPRESSOR CLUTCH CIRCUIT TROUBLESHOOTING ), and repair the problem with the circuit If the A/C compressor clutch circuit is OK, do the A/C compressor clutch check (see A/C COMPRESSOR CLUTCH CHECK ), and repair as needed
    Suction and discharge pressures are abnormally high, but drop rapidly when the compressor disengages	Discharge pressure quickly drops about 196 kPa (28 psi) when the clutch disengages Expansion valve inlet and outlet temperatures are different	There is excess air in the A/C system	Evacuate the A/C system (see SYSTEM EVACUATION ), and recharge it (see SYSTEM CHARGING )
    Suction and discharge pressures are abnormally high, and there is little or no airflow through the A/C condenser	Suction and discharge pressures normalize when water is sprayed on the A/C condenser	The condenser and/or radiator fins are clogged The condenser fins are damaged The condenser and/or radiator fans are not working properly	Clean debris from the condenser and/or radiator fins Comb the condenser fins to repair any damage Troubleshoot the A/C condenser fan and/or the radiator fan circuit(s)
    The suction pressure is high and the discharge pressure is low Both pressures are steady	The liquid line temperature is similar on both sides of expansion valve System pressures do not vary at a steady engine speed	The expansion valve is stuck open	Replace the expansion valve (see EXPANSION VALVE REPLACEMENT )
    The suction pressure is high, the discharge pressure is low, and there are particle contaminants in the refrigerant lines	Metal flakes or Desiccant particles are in the discharge hose or expansion valve	The A/C compressor is malfunctioning	Replace the A/C compressor (see A/C COMPRESSOR REPLACEMENT ) If the system is contaminated with desiccant, replace the receiver/dryer (see RECEIVER/DRYER DESICCANT REPLACEMENT )
    The suction pressure is high, the discharge pressure is low, and the pressures quickly change when the A/C disengages	The discharge and suction pressures equalize soon after the A/C compressor stops	The A/C compressor seal is faulty	Replace the A/C compressor (see A/C COMPRESSOR REPLACEMENT )
    Suction and discharge pressures are both low and none of the refrigerant lines are cold	There is no frost on the expansion valve, and the low-pressure liquid line is not cold	The A/C system has a leak (very low refrigerant charge)	Do the refrigerant leak check (see REFRIGERANT LEAK CHECK ), repair any leaks, and recharge the A/C system (see SYSTEM CHARGING )
    Suction and discharge pressures are both low, and the expansion valve or the suction line is abnormally cold	Expansion valve inlet temperature is much lower than receiver/dryer outlet temperature The low pressure (suction) hose/line is cooler than the evaporator	The discharge hose/line is clogged or kinked, which is restricting refrigerant flow The suction hose/line is clogged or kinked, which is restricting refrigerant flow	Repair or replace the faulty A/C line or hose (see A/C LINE REPLACEMENT )
    Initially, the suction and discharge pressure are normal, but both become abnormally low during operation	During extended operation, the air flow from the vents decreases	The evaporator is freezing up	Run the fan with A/C compressor off to warm the evaporator, then test the evaporator temperature sensor (see EVAPORATOR TEMPERATURE SENSOR TEST ) If necessary, replace the evaporator temperature sensor
    Suction and discharge pressures are both low and there are abnormal temperature changes at the expansion valve	During operation, the suction pressure decreases, and heavy frost occurs on the low pressure liquid line The low pressure liquid line is cold at the expansion valve, but warm after the valve There is frost on the expansion valve	The expansion valve is stuck closed	Replace the expansion valve (see EXPANSION VALVE REPLACEMENT ), and the receiver/dryer (see RECEIVER/DRYER DESICCANT REPLACEMENT ) Check the old expansion valve for contamination If contaminants are found, replace the component that caused the contamination
    The discharge pressure is low, the suction pressure is extremely low, and the expansion valve outlet is abnormally warm	There is no frost on the expansion valve outlet, and the liquid line temperature changes significantly across the expansion valve	There is excessive moisture in the A/C system	Evacuate the A/C system (see SYSTEM EVACUATION ), and replace the receiver/dryer (see RECEIVER/DRYER DESICCANT REPLACEMENT ) Recharge the A/C system (see SYSTEM CHARGING )
    The discharge pressure is low, the suction pressure is extremely low, and the suction line is abnormally cold	There is frost on the line from the evaporator to the compressor	The evaporator is internally contaminated or plugged	Replace the evaporator core (see EVAPORATOR CORE REPLACEMENT )
    The discharge pressure is low, the suction pressure is extremely low, and the refrigerant temperature doesn't change going through the expansion valve	The low pressure liquid line is not cold The liquid line temperatures are similar on both sides of expansion valve	The expansion valve is faulty	Replace the expansion valve (see EXPANSION VALVE REPLACEMENT )
    The discharge pressure is low, the suction pressure is extremely low, and the expansion valve is abnormally cold	There is frost on the expansion valve	Excessive moisture in the system is freezing the expansion valve	Replace the receiver/dryer (see RECEIVER/DRYER DESICCANT REPLACEMENT ) Evacuate the A/C system (see SYSTEM EVACUATION ), and recharge the A/C system (see SYSTEM CHARGING )
    The discharge pressure is low, the suction pressure is extremely low, and the high pressure liquid line is abnormally cold	There is frost on the line from the receiver/dryer to the expansion valve	The receiver/dryer is clogged	Replace the receiver/dryer (see RECEIVER/DRYER DESICCANT REPLACEMENT ) Evacuate the A/C system (see SYSTEM EVACUATION ), and recharge the A/C system (see SYSTEM CHARGING )