Symptom Table

Gauge indication

Refrigerant cycle

Probable cause

Corrective action

Both high and low pressure sides are too high.

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The pressure returns to normal soon after sprinkling water on condenser.

Overfilled refrigerant.

Recover refrigerant, evacuate system, and recharge with the specified amount of refrigerant. Refer to Recycle Refrigerant .

Air flow to condenser is insufficient.

Insufficient condenser cooling performance.

• Poor cooling fan rotation.
• Improper installation of air guides.
• Clogged or dirty condenser fins.

• Repair or replace malfunctioning parts.
• Clean and repair condenser fins.

When compressor is stopped, a high-pressure reading quickly drops by approximately 196 kPa (2 kg/cm² , 28 psi). It then gradually decreases.

Air mixed with refrigerant.

Recover refrigerant, evacuate system, and recharge with the specified amount of refrigerant. Refer to Recycle Refrigerant .

• Low-pressure pipe is cooler than the outlet of evaporator.
• Low-pressure pipe is frosted.

Expansion valve opened too much (excessive flow of refrigerant).

Replace expansion valve.

High-pressure side is excessively high and low-pressure side is too low.

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High-pressure pipe and upper side of condenser become hot, however, liquid tank does not become so hot.

Clogged or crushed high-pressure pipe located between compressor and condenser.

Repair or replace the malfunctioning parts.

High-pressure side is too low and low-pressure side is too high.

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• The readings of both sides become equal soon after compressor operation stops.
• There is no temperature difference between high and low-pressure sides.

Malfunction in compressor system (insufficient compressor pressure operation).

• Damage or breakage of valve.
• Malfunctioning gaskets.

Replace compressor. Refer to Removal and Installation .

Both high and low pressure sides are too low.

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• The area around evaporator outlet does not become cold.
• The area around evaporator inlet becomes frosted.

Clogged expansion valve.

• Breakage of temperature sensor.
• Clogging by foreign material.

Eliminate foreign material from expansion valve or replace it.

• There is a temperature difference between the areas around outlet and inlet pipes of liquid tank.
• Liquid tank becomes frosted.

Malfunction inside liquid tank (clogged strainer).

Replace condenser (includes liquid tank). Refer to Removal and Installation .

Evaporator becomes frosted.

Clogged or crushed low-pressure pipe.

Repair or replace malfunctioning parts.

Malfunction in intake air temperature sensor.

Check intake sensor system. Refer to Diagnosis Procedure .

There is a small temperature difference between the high and low pressure pipes for refrigerant cycle.

• Low refrigerant charge.
• Leak or leaks in A/C system.

• Check for leaks. Refer to Leak Test .
• Recover refrigerant, evacuate system, and recharge with the specified amount of refrigerant. Refer to Recycle Refrigerant .

Low-pressure side sometimes becomes negative.

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• Sometimes the area around evaporator outlet does not become cold.
• Sometimes the area around evaporator inlet is frosted.

• Icing caused by moisture mixed with refrigerant.
• Deteriorated dryer material in liquid tank.

• Recover refrigerant then replace condenser (includes liquid tank). Refer to Removal and Installation .
• Evacuate system and recharge with the specified amount of refrigerant. Refer to Charge Refrigerant .

Hunting in high-pressure side.

There is no temperature difference between high and low-pressure sides.

Malfunctioning variable valve in compressor.

• Replace compressor. Refer to Removal and Installation .
• Check ECV system.