Air Conditioning System

Air Conditioning Cycle Diagnosis

Checking The Refrigerant System With Manifold Gauge
Since Refrigerant-134a (HFC-134a) is used in the air conditioning system in this vehicle, be sure to use manifold gauges, charging hoses and other air conditioning service tools for HFC-134a when checking the refrigerant system.

Conditions:
- Run the engine at idling
- Air conditioning switch is ON
- Run the blower motor at HIGH position
- Temperature control lever set to MAX COLD
- Air source selector lever at CIRC
- Open the engine hood
- Close all the doors

Normal Pressure:
- At ambient temperature: approximately 25 - 30 °C (77 - 86 °F).
- At low-pressure side: approximately 147.1 - 294.2 kPa (21.3 - 42.7 psi).
- At high-pressure side: approximately 1372.9 - 1863.3 kPa (199.1 - 270.2 psi).




HFC-134a Pressure-Temperature Relationship
Refer to the table on the refrigerant pressure-temperature relationship.

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Connect The Manifold Gauge
Low-pressure hose (LOW) - Suction side
High pressure hose (HI) - Discharge side





Magnetic Clutch Diagnosis
When the air conditioning switch and the fan control knob (tan switch) are turned on with the engine running, current flows through the thermostat and the compressor relay to activate the magnetic clutch.
The air conditioning can be stopped by turning off the air conditioning switch or the fan control knob (fan switch). However, even when the air conditioning is in operation, the electronic thermostat, the pressure switch or the Powertrain Control Module (PCM) is used to stop the air conditioning temporarily by turning off the magnetic clutch in the prearranged conditions to reduce the engine load which is being caused by the rise in the engine coolant temperature, and the acceleration of the vehicle, etc.
For the inspection of the relays, switches and units in the table, refer to Individual Inspection .

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Magnetic Clutch Does Not Run