A/C System Performance Testing

1. Confirm that vehicle and environmental conditions are as follows.
- Vehicle is not exposed to direct sun.
- Ambient temperature is within 15 - 35 °C (59 - 95 °F).




2. Make sure that high pressure valve (1) and low pressure valve (2) of manifold gauge (3) are firmly closed.
3. Connect high pressure charging hose (4) to high pressure service valve (5) on vehicle, and connect low pressure charging hose (6) to low pressure service valve (7) on vehicle.
4. Bleed the air in charging hoses (3), (4) by loosening their respective nuts on manifold gauge, utilizing the refrigerant pressure When a hiss is heard, immediately tighten nut.

CAUTION: Do not interchange high and low pressure charging hoses by mistake.

5. Warm up engine to normal operating temperature (engine coolant temperature at 80 - 90 °C (176 - 194 °F)) and keep it at specified idle speed.
6. Operate A/C at the following conditions.
- Main (front) A/C switch at ON position
- Rear A/C main switch at ON position (if equipped).
- Front blower motor switch at max position.
- Rear blower motor switch at max position (if equipped).
- Air outlet control button at face position.
- Temperature control lever at max cool position.
- Vehicle door at all open.
- Air inlet door at recirculation position.

7. Keep all windows, doors and engine food open.




8. With about 20 mm (0.8 in.) of dry bulb thermometer (1) inserted into center face air outlet (2), rear A/C air outlet (3) (dual A/C model only) and near A/C evaporator air inlet, read temperature indicated on each thermometer.







9. Check for each pressure of low side and high side if it is within shaded range of graph.
If each gauge reading is out of specified pressure, correct defective part referring to "PERFORMANCE DIAGNOSIS TABLE".

NOTE: Pressure registered on gauge varies with ambient temperature. Therefore, use the graphs when determining if pressures are normal or not.




10. Check inlet port temperature-to-outlet port temperature relationship using graph.
For example, if A/C evaporator inlet port temperature is 25 °C (77 °F) and center face air outlet temperature is 8 °C (46.4 °F), their crossing point is within acceptable range as shown in graph.

11. If crossing point is out of acceptable range, diagnose trouble referring to "PERFORMANCE DIAGNOSIS TABLE".
12. Check that difference in temperature of center face air outlet air and rear A/C air outlet air are within 5 °C (41 °F). If the rear A/C air outlet air temperature is higher over 5 °C (41 °F) than center face air outlet air temperature, check rear A/C unit.

High Pressure Gauge:

Low Pressure Gauge:

Thermometer At Center Duct:

PERFORMANCE DIAGNOSIS TABLE

NOTE: If ambient temperature is within 30 - 35 °C (85 - 95 °F), it is possible to do using "DETAIL DIAGNOSIS TABLE" for detail diagnosis.




DETAIL DIAGNOSIS TABLE (AT AMBIENT TEMPERATURE WITHIN 30 - 35 °C (85 - 95 °F))