Component Function Check
Whenever system's high and/or low side pressure is abnormal, diagnose using a manifold gauge. The marker above the gauge scale in the following tables indicates the standard (usual) pressure range. Since the standard (usual) pressure, however, differs from vehicle to vehicle, refer to Inspection (Ambient air temperature-to-operating pressure table).
Both High- and Low-pressure Sides are Too Low
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Gauge indication |
Refrigerant cycle |
Probable cause |
Corrective action |
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Both high- and low-pressure sides are too low. |
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Liquid tank inside is slightly clogged. |
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High-pressure pipe located between liquid tank and expansion valve is clogged. |
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Expansion valve and liquid tank are warm or only cool when touched. |
Low refrigerant charge. Leaking fittings or components. |
Check refrigerant system for leaks. Refer to Leak Test . |
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There is a big temperature difference between expansion valve inlet and outlet while the valve itself is frosted. |
Expansion valve closes a little compared with the specification.
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An area of the low-pressure pipe is colder than areas near the evaporator outlet. |
Low-pressure pipe is clogged or crushed. |
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Airflow volume is too low. |
Evaporator is frozen. |
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