Fusion AWD V6-3.5L (2010)
Expansion Block/Orifice Tube: Description and Operation
A/C Pressure Transducer
Air Conditioning
The refrigerant system components include the following:
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Pulley-driven A/C compressor (non-hybrid)
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Electric A/C compressor (hybrid)
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A/C clutch assembly (non-hybrid)
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A/C condenser core
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A/C evaporator core
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Receiver/drier cartridge
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Connecting refrigerant lines
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Thermostatic Expansion Valve (TXV)
The refrigerant system incorporates an A/C compressor controlled by the PCM through an A/C clutch relay. The HVAC module sends an A/C request
signal to the Instrument Cluster (IC), which relays the request to the PCM. An evaporator discharge air temperature sensor is used to disengage the A/C
compressor clutch when the evaporator core temperature falls below an acceptable temperature.
The A/C compressor clutch will only be engaged by the PCM if all of the following conditions are met:
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The HVAC module is set to a mode which provides an A/C request to the PCM via the IC.
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The evaporator discharge air temperature sensor is reading an acceptable temperature.
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The A/C pressure transducer is reading an acceptable pressure in the high side of the refrigerant system.
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The A/C compressor relay is switched to the closed position by the PCM.
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The engine coolant temperature is not excessively high.
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The PCM has not detected a Wide Open Throttle (WOT) condition.
NOTE: To prevent erroneous readings that can result from underhood heat sources, the PCM uses data from several sources to calculate ambient
temperature. The vehicle must be driven for a sufficient time, speed and distance after startup before the calculated ambient temperature is updated in the
PCM. If a vehicle is moved from a below-freezing environment to a warm environment (such as being moved from outside into a garage or when
delivered from a cold climate to a warm climate), the minimal amount of driving may not be sufficient for the calculated ambient temperature to be
updated. In this event, the PCM will believe the ambient temperature is too low for A/C operation and, to prevent an increased risk of compressor
slugging or damage, will not engage the A/C compressor in any mode. To manually reset the PCM calculated ambient temperature to the current
temperature, run the vehicle until the thermostat opens and then clear the PCM Keep Alive Memory (KAM). For the KAM resetting procedure, refer to
Computers and Control Systems Information. When the PCM KAM is reset, the ambient temperature will reset to the current higher value (a value closer
to actual surrounding conditions) and the A/C compressor will operate normally.
An A/C pressure relief valve is installed in the A/C compressor to protect the refrigerant system against excessively high refrigerant pressures.
Refrigerant flow into the evaporator core is metered by a TXV.
A/C Pressure Transducer
The A/C pressure transducer monitors the compressor discharge pressure and sends a variable voltage signal representing the pressure to the PCM. The
PCM will interrupt A/C compressor operation (non-hybrid), or decrease the electric A/C compressor speed (hybrid) in the event that the A/C pressure
transducer indicates high system discharge pressures. It is also used to sense low charge conditions. If the pressure is below a predetermined value for a
given ambient temperature, the PCM will not allow the A/C compressor to operate.
The A/C pressure transducer is located on the high-pressure side of the TXV manifold and tube assembly near the TXV fitting. It is necessary to recover
the refrigerant before removing the A/C pressure transducer.
