Ford Ecosport: Climate Control System - General Information / Description and Operation - Climate Control System - Vehicles With: Electronic Manual Temperature Control (EMTC) - System Operation and Component Description

System Diagram

System Operation

Network Message Chart

  Module Network Input Messages — Powertrain Control Module (PCM)

  Module Network Input Messages — Heating, Ventilation, and Air Conditioning (HVAC) Control Module

The Refrigerant Cycle

For information regarding basic HVAC system refrigerant operation, refer to the current Ford Web Based Technical Training courses. The following diagram shows the refrigerant system state in each component.

For information regarding basic HVAC system refrigerant operation, refer to the current Ford Web Based Technical Training courses. The following diagram shows the refrigerant system state in each component.

The following are characteristics of the EMTC system:

The PCM controls the A/C clutch relay.

The evaporator temperature sensor monitors the temperature of the evaporator core and sends a signal to the PCM . If the temperature of the evaporator core is low enough to cause the condensed water vapor to freeze, the PCM disengages the A/C clutch relay.

The line pressure is monitored so that A/C compressor operation capacity may vary and may be interrupted if the system pressure becomes too high or too low.

The A/C compressor relief valve opens and vents refrigerant to relieve unusually high system pressure.

A/C Flow and State

Control System Logic

When the customer directly inputs an A/C request into the HVAC control module, the module sends the request to the GWM over the MS-CAN . The GWM relays the request to the PCM over the HS-CAN1 . The PCM controls the A/C clutch relay.

A/C (Air Conditioning) Request

When an A/C request is received by the PCM , the PCM engages the A/C clutch relay when all the following conditions are met:

• Excessively high or low refrigerant pressure from the A/C pressure transducer is not detected.
• Engine coolant temperature conditions are within normal parameters.
• Ambient air temperature is above approximately 4ºC (39ºF).
• Wide Open Throttle (WOT) condition is not present.
• Evaporator temperature is above approximately 5ºC (41ºF).
• Engine torque conditions are within normal parameters.
• Battery state of charge conditions are within normal parameters.

Compressor control and the evaporator temperature are a function of many parameters, not just a straight on/off, to avoid freezing the evaporator. The PCM monitors multiple temperature sensors for correlation including, but not limited to, AAT, CACT, CHT, ECT, IAT, IAT2, MAF, MAPT, TCB and TCIPT (as applicable). The PCM runs this logic after an engine off and a calibrated soak period of 6 to 8 hours. This soak period allows the Ambient Air Temperature (AAT) sensor and the other temperature sensors to stabilize and not differ by greater than a calibrated value, typically 18ºC (32.4ºF). If a temperature sensor input is found to be reporting a temperature imbalance the PCM does not allow the A/C clutch to engage. For more information on PCM sensors, Refer to Powertrain Control/Emissions Diagnosis (PC/ED) manual.

The PCM monitors the discharge pressure measured by the A/C pressure transducer. The PCM interrupts A/C compressor operation in the event 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 does not allow the A/C clutch to engage.

The HVAC control module adjusts the system based on cabin temperature. If equipped with the in-vehicle and humidity sensor, the HVAC control module also adjusts the air inlet door depending on the humidity measured by the in-vehicle temperature and humidity sensor. If the vehicle cabin becomes too humid and recirculated air is selected, the HVAC control module adjusts the air inlet door to allow more fresh air. When the humidity level drops, it adjusts back to partial recirculated air.

Heating and Ventilation

The heating and ventilation system:

• controls the temperature of the air inside the vehicle.
• reduces the relative humidity of the air inside the vehicle (during A/C compressor operation).
• delivers heated or cooled air to maintain the vehicle interior temperature and comfort level.

The heating and ventilation system uses a reheat method to provide conditioned air to the passenger compartment. Temperature blending is controlled by the temperature door, which regulates the amount of air that flows through and around the heater core, where it is then mixed and distributed. All airflow from the blower motor passes through the A/C evaporator core.

Sensor Inputs

The evaporator temperature sensor is an input to the HVAC control module and the information is relayed to the PCM over the CAN . The Ambient Air Temperature (AAT) sensor is an input to the PCM . The PCM sends the Ambient Air Temperature (AAT) sensor information to the HVAC control module. If the temperatures are below a predetermined value, the PCM does not allow the A/C clutch to engage.

Air Handling

There are 3 door actuators that control the air flow into the passenger compartment:

• Air distribution
• Air inlet
• Temperature

The 2 circuit type Air inlet door actuator contains only a reversible electric motor. The 5 circuit type Air Inlet, Air distribution and Temperature door actuators contain a reversible electric motor and a potentiometer. The potentiometer circuits consist of a 5-volt reference signal connected to one end of a variable resistor, and a signal ground connected to the other. A signal circuit is connected to a contact wiper, which is driven along the variable resistor by the actuator shaft. The signal to the HVAC control module from the contact wiper indicates the position of the actuator door. The HVAC control module powers the actuator motors to move the doors to the desired positions. The desired door positions are calculated by the HVAC control module based on the set temperature, in-vehicle temperature (if equipped the in-vehicle temperature and humidity sensor), and ambient air temperature.

When an airflow mode, desired temperature, fresh air, or recirculation mode is selected, the HVAC control module moves the actuator motor in the desired direction.

The HVAC control module sends a PWM signal to the blower motor speed control to regulate the blower speed as necessary. The blower motor speed control provides variable ground feed for the blower motor based on the input from the HVAC control module. A delay function provides a gradual increase or decrease in blower motor speed under all conditions.

OFF

When OFF is selected:

• the air inlet door closes, preventing outside air and allowing only recirculated air.
• the blower motor is off.

MAX A/C

When MAX A/C is selected:

• the air inlet door closes, preventing outside air and admits only recirculated air.
• the recirculated air indicator is illuminated (recirculated air forced on).
• the mode doors direct airflow to the instrument panel registers.
• the temperature door moves to the full cool position. Air temperature can be manually overridden.
• the A/C button is illuminated.
• the A/C compressor operates if the outside temperature is above approximately 4ºC (39ºF).
• the blower motor is commanded to the highest speed. The blower motor speed is adjustable.

PANEL

When PANEL mode is selected:

• the recirculated air request button is enabled. If the recirculated air request button is selected (indicator on), the air inlet door closes, preventing outside air from entering the passenger compartment. If the recirculated air request button is not selected (indicator off), the air inlet door opens, allowing only outside air into the passenger compartment.
• the mode doors direct airflow to the instrument panel registers.
• the recirculated air request button can be enabled.
• blended air temperature is available. The airflow temperature can only be cooled below the outside air temperature when the A/C is commanded on.
• the blower motor is on and the speed is adjustable.

PANEL/FLOOR

When PANEL/FLOOR mode is selected:

• the recirculated air request button is enabled. If the recirculated air request button is selected (indicator on), the air inlet door closes, preventing outside air from entering the passenger compartment. If the recirculated air request button is not selected (indicator off), the air inlet door opens, allowing only outside air into the passenger compartment.
• the mode doors direct airflow to the floor duct and the instrument panel registers. A small amount of airflow from the defroster duct and side window demisters is present.
• blended air temperature is available. The airflow temperature can only be cooled below the outside air temperature when the A/C is commanded on.
• the blower motor is on and the speed is adjustable.

FLOOR

When FLOOR mode is selected:

• the recirculated air request button is enabled. If the recirculated air request button is selected (indicator on), the air inlet door closes, preventing outside air from entering the passenger compartment. If the recirculated air request button is not selected (indicator off), the air inlet door opens, allowing only outside air into the passenger compartment.
• the mode doors direct airflow to the floor duct. A small amount of airflow from the defroster duct and side window demisters is present.
• blended air temperature is available. The airflow temperature can only be cooled below the outside air temperature when the A/C is commanded on.
• the blower motor is on and the speed is adjustable.

FLOOR/DEFROST

When FLOOR/DEFROST mode is selected:

• the recirculated air request button is enabled. If the recirculated air request button is selected (indicator on), the air inlet door closes, preventing outside air from entering the passenger compartment. If the recirculated air request button is not selected (indicator off), the air inlet door opens, allowing only outside air into the passenger compartment.
• the mode doors direct airflow to the floor duct, the defroster duct and the side window demisters.
• blended air temperature is available.
• the A/C request button toggles the indicator on and off. To reduce fogging, the A/C compressor operates automatically, regardless of indicator status, if the outside temperature is above approximately 4ºC (39ºF).
• the blower motor is on and the speed is adjustable.

DEFROST

When DEFROST is selected:

• the recirculated air request button is disabled. The air inlet door opens, allowing only outside air into the passenger compartment.
• the mode doors direct airflow to the defroster duct and side window demisters. A small amount of airflow from the floor duct is present.
• the A/C is on in defrost. The A/C compressor operates as long as the outside temperature is above approximately 4ºC (39ºF).
• blended air temperature is available.
• the blower motor is on and the speed is adjustable.

Component Description

Component Description

Heating Ventilation Air Conditioning (HVAC) Control Module - Electronic Manual Temperature Control (EMTC)

The EMTC HVAC control module is on the MS-CAN and sets DTC s. A/C requests are sent to the GWM and then to the PCM via the HS-CAN1 .

The temperature control switch adjusts the discharge air temperature. Movement of the temperature knob from cool to warm causes a corresponding movement of the temperature door. The position of the temperature door determines the discharge air temperature. The temperature control selector is an integral part of the HVAC control module and cannot be serviced separately.

The airflow mode setting adjusts the discharge air outlet location. Each airflow mode selector icon causes a corresponding movement of the airflow mode doors and determines the discharge air outlet location. The airflow mode selector knob is an integral part of the HVAC control module and cannot be serviced separately.

The A/C button determines A/C compressor operation, except when the temperature selector is set to MAX A/C or the airflow mode selector is in Defrost mode. The A/C button is an integral part of the HVAC control module and cannot be serviced separately.

The recirculated air request button can be activated in any mode except Defrost. In MAX A/C mode the recirculated air indicator is illuminated (recirculated air forced on). The recirculated air request button is an integral part of the HVAC control module and cannot be serviced separately.

Blower Motor Speed Control

The blower motor speed control uses a PWM signal from the HVAC control module to determine the desired blower speed and varies the ground feed for the blower motor to control the speed.

Instrument Panel Console Switch Assembly - Auto Start-Stop Deactivation Switch (if equipped)

The Instrument Panel Console Switch Assembly - Auto Start-Stop deactivation switch is available on vehicles equipped with Auto Start-Stop feature only. Auto Start-Stop deactivation switch is a momentary contact switch that includes a LED indicator. This switch is used to deactivate the Auto Start-Stop mode. Refer to the Owner's Literature, Unique Driving Characteristics, for full Auto Start-Stop enabling/disabling information.

Cabin Heater Coolant Pump - vehicles equipped with Auto Start-Stop (if equipped)

The cabin heater coolant pump is available on vehicles equipped with Auto Start-Stop feature only. The cabin heater coolant pump provides coolant to the heater core whenever the HVAC system requests heat and the vehicle is in Auto Start-Stop mode. Refer to the Owner's Literature, Unique Driving Characteristics, for full Auto Start-Stop enabling/disabling information.

The PCM sends a PWM signal to the cabin heater coolant pump based upon the:

• Auto Start-Stop mode enabled
• HVAC system temperature control setting (requesting heat)
• Ambient air temperature
• Engine coolant temperature
• Engine Revolutions Per Minute (RPM)
• Vehicle speed

Climate Control Housing

All airflow from the blower motor passes through the evaporator core. The airflow is then directed through or around the heater core by the temperature door where it is then mixed and distributed to the selected outlet by the airflow mode doors.

Ambient Air Temperature (AAT) Sensor

The Ambient Air Temperature (AAT) sensor is an input to the PCM . If the outside air temperature is below approximately 0°C (32°F), the PCM does not allow the A/C compressor clutch to engage. The PCM sends raw ambient air temperature data to the HVAC control module. The HVAC control module filters the raw data, sends it to the APIM and the touchscreen displays the outside temperature.

After replacing an Ambient Air Temperature (AAT) sensor, the sensor data must be reset by following the menu prompts on the FDRS scan tool.
Refer to: Reset the Outside Air Temperature Sensor Learned Values (412-00 Climate Control System - General Information, General Procedures).

Air Conditioning (A/C) Compressor Clutch Assembly

When battery voltage is applied to the A/C compressor clutch field coil, the clutch plate and hub assembly is drawn toward the A/C clutch pulley. The magnetic force locks the clutch plate and hub assembly and the A/C clutch pulley together as one unit, causing the compressor shaft to rotate with the engine. When battery voltage is removed from the A/C compressor clutch field coil, springs in the clutch plate and hub assembly move the clutch plate away from the A/C clutch pulley.

An A/C clutch diode is integrated into the coil for A/C clutch field coil circuit spike suppression.

Air Conditioning (A/C) Condenser

The A/C condenser is an aluminum fin-and-tube design heat exchanger. It cools compressed refrigerant gas by allowing air to pass over fins and tubes to extract heat, and condenses gas to liquid refrigerant as it is cooled.

Air Conditioning (A/C) Pressure Transducer

The PCM monitors the discharge pressure measured by the A/C pressure transducer. As the refrigerant pressure changes, the resistance of the A/C pressure transducer changes.

A 5-volt reference voltage is supplied to the A/C pressure transducer from the PCM . The A/C pressure transducer receives a ground from the PCM . The A/C pressure transducer then sends a voltage to the PCM to indicate the A/C refrigerant pressure.

It is not necessary to recover the refrigerant before removing the A/C pressure transducer.

Ambient Air Quality Sensor (if equipped)

The ambient air quality sensor is an input to the HVAC control module. When pollution and bad odors coming from the external environment are detected, the air inlet door automatically closes.

Door Actuator - Air Distribution

The air distribution door actuator contains a reversible electric motor and potentiometer. The potentiometer allows the HVAC control module to monitor the position of the airflow mode door. The HVAC control module drives the actuator motor in the direction necessary to move the airflow mode doors to the position set by the mode selector knob.

Door Actuator - Air Inlet (2 circuit)

The 2 circuit air inlet door actuator moves the air inlet door between the fresh and recirculated air positions on command from the HVAC control module. The 2 circuit air inlet door actuator is driven to, and automatically stops at the full recirculated air or full fresh air inlet position and does not require a potentiometer circuit to monitor its position. The 2 circuit air inlet door does not stop at any point between the recirculated air or fresh air inlet position.

Door Actuator - Air Inlet (5 circuit)

The 5 circuit air inlet door actuator contains a reversible electric motor and potentiometer. The potentiometer allows the HVAC control module to monitor the position of the air inlet door.

Door Actuator - Temperature

The temperature door actuator contains a reversible electric motor and potentiometer. The potentiometer allows the HVAC control module to monitor the position of the temperature door. The HVAC control module drives the temperature door actuator motor in the direction necessary to move the temperature door to the position set by the temperature selection knob.

Evaporator Temperature Sensor

The evaporator temperature sensor measures the temperature of the evaporator core. The evaporator temperature sensor contains a thermistor. The sensor varies its resistance with the temperature. As the temperature rises, the resistance falls. As the temperature falls, the resistance rises. The evaporator temperature sensor is an input to the HVAC control module which sends the information to the GWM over the MS-CAN . The GWM relays the sensor information to the PCM over the HS-CAN1 . An accurate evaporator temperature is critical for compressor engagement.

Internally Controlled Variable Displacement Compressor (1.5L diesel, 1.5L M/T)

NOTE: Proper Air Conditioning (A/C) system diagnosis on a vehicle's compressor is dependent on correct refrigerant system charge and tested in ambient temperatures above 21.1°C (70°F).

Variable displacement compressor internals are similar to fixed displacement compressors. The pistons are placed around an angled plate (swash plate) and are pushed back and forth as the plate rotates. Variable displacement compressors vary the swash plate angle to allow piston displacement to vary from 5% (default) to 100% of full capacity to meet cooling demand.

The internally controlled variable displacement A/C compressor has:

• a non-serviceable shaft seal.
• a non-serviceable pressure relief valve installed in the rear of the compressor to protect the refrigerant system against excessively high refrigerant pressures.
• Refer to Specifications in Group 412 for the appropriate refrigerant and refrigerant oil. This oil contains special additives required for the A/C compressor. The oil may have some slightly dark-colored streaks while maintaining normal oil viscosity. This is normal for this A/C compressor because of break-in wear that can discolor the oil.

The piston displacement of the internally controlled variable displacement compressor is controlled with a bellows actuated control valve located in the compressor rear head. The control valve senses the refrigerant suction and head pressures and regulates the pressure in the compressor crankcase. Swash plate angle is a result of the balance of the crankcase pressure on one side of the pistons and suction and head pressure on the other side. The suction pressure varies with the evaporator core temperature. The valve regulates the amount of refrigerant being discharged by an optimum compressor displacement, resulting in the requested evaporator core temperature of approximately 3°C (37.4°F).

Externally Controlled Variable Displacement Compressor (1.0L, 1.5L A/T, 2.0L)

NOTE: Proper Air Conditioning (A/C) system diagnosis on a vehicle's compressor is dependent on correct refrigerant system charge and tested in ambient temperatures above 21.1°C (70°F).

The externally variable displacement A/C compressor has:

• a non-serviceable shaft seal.
• a non-serviceable pressure relief valve installed in the rear of the compressor to protect the refrigerant system against excessively high refrigerant pressures.
• Refer to Specifications in Group 412 for the appropriate refrigerant and refrigerant oil. This oil contains special additives required for the A/C compressor. The oil may have some slightly dark-colored streaks while maintaining normal oil viscosity. This is normal for this A/C compressor because of break-in wear that can discolor the oil.

Variable displacement compressors have a swash plate that rotates to reciprocate pistons, which compresses refrigerant. Variable displacement compressors change the swash plate angle to change the refrigerant displacement. The externally controlled variable displacement compressor changes the swash plate angle in response to an electrical signal from the PCM . The externally controlled variable displacement compressor manages displacement by controlling refrigerant differential pressure before and after a throttle at the discharge side; achieving precise cooling capability control in response to cabin environment and driving conditions.

The PCM sends a PWM signal to the solenoid in the compressor to control the compressor displacement based upon the:

• Ambient air temperature
• Evaporator temperature
• Engine RPM (revolutions per minute)
• Vehicle speed
• A/C high side pressure
• Temperature and mode settings of the climate control head
• Intake air temperature

Evaporator Core

The evaporator core is an aluminum plate/fin type and is located in the climate control housing. A mixture of liquid refrigerant and oil enters the evaporator through the evaporator inlet tube and continues out of the evaporator through the evaporator outlet tube as a vapor. During A/C compressor operation, airflow from the blower motor is cooled and dehumidified as it flows through the evaporator fins.

Heater Core

The heater core consists of fins and tubes arranged to extract heat from the engine coolant and transfer it to air passing through the heater core.

Internal Heat Exchanger (IHX)

The evaporator inlet and outlet manifold incorporates the Internal Heat Exchanger (IHX) and is serviced as an assembly. The Internal Heat Exchanger (IHX) combines a section of the A/C suction and liquid refrigerant lines into one component. It uses the cold vapor from the evaporator to cool the hot liquid from the condenser before it enters the Thermostatic Expansion Valve (TXV). After the Thermostatic Expansion Valve (TXV), more liquid refrigerant is available for absorbing heat in the evaporator. The result is an increase in cooling and operating efficiency of the HVAC system.

Receiver Drier

The receiver drier stores high-pressure liquid and the desiccant bag mounted inside the receiver drier removes any retained moisture from the refrigerant.

Refrigerant System Dye

A fluorescent refrigerant system dye wafer is added to the receiver drier desiccant bag at the factory to assist in refrigerant system leak diagnosis. This fluorescent dye wafer dissolves after about 30 minutes of continuous A/C operation. It is not necessary to add additional dye to the refrigerant system before diagnosing leaks, even if a significant amount of refrigerant has been removed from the system.
Refer to: Fluorescent Dye Leak Detection - Vehicles With: R134A Refrigerant (412-00 Climate Control System - General Information, General Procedures).

Replacement desiccant bags, either separately or part of the receiver drier assembly, are equipped with a new fluorescent dye wafer. It is not necessary to add additional dye to the refrigerant system before diagnosing leaks. If the system has been out of refrigerant through the winter the dye at the leak point may have oxidized and may not fluoresce. If this happens, recharge and operate the A/C system to circulate the oil and allow any residual dye to show up at the leak point. It is important to understand that dye adheres to the oil not the refrigerant; the refrigerant carries the oil out of the leak point.

NOTE: Check for leaks using a Rotunda-approved UV (ultraviolet) lamp and dye enhancing glasses.

Service Gauge Port Valves

The service gauge port fitting is an integral part of the refrigerant line or component.

• Prior to leak testing, blow air over the service gauge port valves to ensure an accurate test.
• Special couplings are required for both the high-side and low-side service gauge ports.
• A very small amount of leakage around the Schrader-type valve with the service gauge port valve cap removed is considered normal. Install a new Schrader-type valve core if the seal leaks excessively.
• The A/C service gauge port valve caps are used as primary seals in the refrigerant system to prevent leakage through the Schrader-type valves from reaching the atmosphere. Always install and tighten the A/C service gauge port valve caps to the correct torque after they are removed.
• Follow the procedure and the notes for electronic leak testing.
  Refer to: Electronic Leak Detection - Vehicles With: R134A Refrigerant (412-00 Climate Control System - General Information, General Procedures).
  

Thermostatic Expansion Valve (TXV)

The Thermostatic Expansion Valve (TXV) is located at the evaporator core inlet and outlet tubes at the center rear of the engine compartment. The Thermostatic Expansion Valve (TXV) provides a restriction to the flow of refrigerant and separates the low-pressure and high-pressure sides of the refrigerant system. Refrigerant entering and exiting the evaporator core passes through the Thermostatic Expansion Valve (TXV) through 2 separate flow paths. An internal temperature sensing bulb senses the temperature of the refrigerant flowing out of the evaporator core and adjusts an internal pin-type valve to meter the refrigerant flow into the evaporator core. The internal pin-type valve decreases the amount of refrigerant entering the evaporator core at lower temperatures and increases the amount of refrigerant entering the evaporator core at higher temperatures.