Performance Test

The performance test will help determine if the air conditioner system is operating within specifications.

Use only service equipment that is U.L.-listed and is certified to meet the requirements of SAE J2210 to remove HFC-134a (R-134a) from the air conditioning system.

If accidental system discharge occurs, ventilate work area before resuming service.

R-134a service equipment or vehicle air conditioning systems should not be pressure tested or leak tested with compressed air.

Additional health and safety information may be obtained from the refrigerant and lubricant manufacturers.

1. Connect an R-134a refrigerant recover/recycling/charging station to the high-pressure service port and the low-pressure service port, following the equipment manufacturer's instructions.
2. Determine the relative humidity and air temperature.
3. Remove the glove box (see GLOVE BOX REMOVAL/INSTALLATION ).
4. Insert a thermometer (A) in the center vent, and place a thermometer (B) near the blower unit.
   Fig 1: Inserting Thermometer In Center Vent

   Courtesy of AMERICAN HONDA MOTOR CO., INC.
5. Test conditions:
   • Avoid direct sunlight.
   • Open the hood.
   • Open the front doors.
   • Set the temperature control dial on Max Cool, the mode control switch on Vent and the recirculation control switch on Recirculate.
   • Turn the A/C switch on and the fan switch on Max.
   • Run the engine at 1,500 RPM.
   • No driver or passengers in vehicle.
6. 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 high and low system pressure from the A/C gauges.
7. To complete the charts:
   • Mark the delivery temperature along the vertical line.
   • Mark the intake temperature (ambient air temperature) along the bottom line.
   • Draw a line straight up from the air temperature to the humidity.
   • Mark a point 10% above and 10% below the humidity level.
   • From each point, draw a horizontal line across the delivery temperature.
   • The delivery temperature should fall between the two lines.
   • Complete the low-side pressure test and high-side pressure test in the same way.
   • Any measurements outside the line may indicate the need for further inspection.

   Example 

   • Intake temperature (dry): 86°F (30°C) Humidity level 70%
   • Intake temperature (wet): 77.9°F (25.5°C)
   • Intake pressure: 276 kPa (2.8 kgf/cm² ) (40.0 psi)
   • Delivery temperature: 62.6°F (17.0°C)
   • Delivery pressure: 1,640 kPa (16.7 kgf/cm² ) (237.9 psi)

   Results:  within normal range

   Fig 2: A/C System Test Graph

   Courtesy of AMERICAN HONDA MOTOR CO., INC.
   A/C SYSTEM TEST
   
   

   Test results	Related symptoms	Probable cause	Remedy
   Discharge (high) pressure abnormally high	After stopping A/C compressor, pressure drops to about 200 kPa (2.0 kgf/cm2 , 28 psi) quickly, and then falls gradually.	Air in system	Recover, evacuate (see REFRIGERANT RECOVERY ), and recharge with specified amount (see SYSTEM CHARGING ).
   	Reduced or no airflow through A/C condenser	Clogged A/C condenser or radiator fins A/C condenser or radiator fan not working properly	Clean. Check voltage and fan RPM. Check fan direction.
   	Line to A/C condenser is excessively hot.	Restricted flow of refrigerant in system	Restricted lines.
   Discharge pressure abnormally low	High and low pressures are balanced soon after stopping A/C compressor. Low side is higher than normal.	Faulty A/C compressor discharge valve Faulty A/C compressor seal	Replace the A/C compressor.
   	Outlet of expansion valve is not frosted, low-pressure gauge indicates vacuum.	Faulty expansion valve Moisture in system	Replace. Recover, evacuate, and recharge with specified amount.
   Suction (low) pressure abnormally low	Expansion valve is not frosted, and low-pressure line is not cold. Low-pressure gauge indicates vacuum.	Frozen expansion valve (Moisture in system) Faulty expansion valve	Recover, evacuate, and recharge with specified amount. Replace the expansion valve.
   	Discharge temperature is low, and the airflow from vents is restricted.	Frozen evaporator	Run the fan with A/C compressor off, then check evaporator temperature sensor.
   	Expansion valve is frosted.	Clogged expansion valve	Clean or replace.
   	Receiver/dryer outlet is cool, and inlet is warm (should be warm during operation).	Clogged receiver/dryer	Replace.
   Suction pressure abnormally high	Low-pressure hose and check joint are cooler than the temperature around evaporator.	Expansion valve open too long Loose expansion capillary tube	Repair or replace.
   	Suction pressure is lowered when A/C condenser is cooled by water.	Excessive refrigerant in system	Recover, evacuate, and recharge with specified amount.
   	High and low-pressures are equalized as soon as the A/C compressor is stopped, and both gauges fluctuate while running.	Faulty gasket Faulty high-pressure valve Foreign particle stuck in high-pressure valve	Replace the A/C compressor.
   Suction and discharge pressures abnormally high	Reduced airflow through A/C condenser.	Clogged A/C condenser or radiator fins A/C condenser or radiator fan not working properly	Clean. Check voltage and fan RPM. Check fan direction.
   Suction and discharge pressures abnormally low	Low-pressure hose and metal end areas are cooler than evaporator.	Clogged or kinked low-pressure hose parts	Repair or replace.
   	Temperature around expansion valve is too low compared with that around receiver/dryer.	Clogged high-pressure line	Repair or replace.
   Refrigerant leaks	A/C compressor clutch is dirty.	A/C compressor shaft seal leaking	Replace the A/C compressor.
   	A/C compressor bolt(s) are dirty.	Leaking around bolt(s)	Tighten bolt(s) or replace A/C compressor.
   	A/C compressor gasket is wet with oil.	Gasket leaking	Replace the A/C compressor.
   	A/C fitting is dirty.	Leaking O-ring	Clean A/C fitting and replace O-ring.