64 01 04 (090)

Integrated heating control and climate control

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Introduction

In this BMW Service Technology, the following heating and air-conditioning systems are described:

> E8x, E9x
> E7x
  • Integrated automatic heating and air conditioning system in basis version (IHKA Basis)

    [System overview ...]

  • High version of the integrated heating and air conditioning automatic system (IHKA High) with left-right separation for driver's and passenger's side

    [System overview ...]

  • Integrated automatic heating and air-conditioning system in High version (IHKA High) with left-right separation for the driver's side and passenger's side and automatic rear air-conditioning system (FKA) with left-right separation in the rear passenger compartment.

    [System overview ...]

  • Overview of IHKA components in the Basic and High versions

    [System overview ...]

IHR, IHKR and IHKA in the E8x, E9x

The heating and air conditioning systems are air-controlled heating and air conditioning systems. The IHKA has separate settings for the driver's side and passenger's side.

>E8x

The 1 Series is equipped as standard with the integrated heating control (IHR). The integrated automatic heating/air-conditioning system (IHKA) is available as optional equipment (option 534).

  • From 12/2004, the integrated heating / air-conditioning control (IHKR) is available as optional equipment for all four-cylinder models (option 530).

    The integrated heating / air-conditioning regulation (IKHR) is the standard equipment for the six-cylinder models.

>E9x

The 3 Series is equipped as standard with integrated heating / air-conditioning regulation (IHKR). The integrated automatic heating/air-conditioning system (IHKA) is available as optional equipment (option 534).

New for heating and air conditioning systems:

  • An electric auxiliary heater working on the PTC principle (positive temperature coefficient) is installed on vehicles with diesel engines.

    The electric auxiliary heater is a separate component and is installed in the heating and air-conditioning unit. The electric auxiliary heater consists of electrically heated heating chains. Air is heated directly by these heating chains and is then fed through the air vents into the passenger compartment. In principle, the electric auxiliary heater works like an electric radiator.

    The electric auxiliary heater accelerates the heating of the passenger compartment, especially at low ambient temperatures and during the cold-start phase.

  • LIN bus (Local Interconnect Network bus)

    A LIN bus serves to actuate flap motors and the electric auxiliary heater in the heating/air-conditioning system.

  • Convertible program (only E93)

    When the soft top is opened and the air-conditioning system is in automatic mode, the convertible program is automatically activated.

    The convertible program adapts the air-conditioner settings (blower, airflow, temperature) to the conditions created by the open soft top. The settings do not have to be changed when the soft top is opened or closed.

    The convertible program is stored in the IHKA control unit.

  • Air distribution flap motor and microswitch (IHR, IHKR only)

    The air distribution flap motor replaces the mechanical actuation of the central kinematics with a cam disc. The central kinematics are still used to mechanically adjust the air distribution flaps. Air distribution (defrost, ventilation, footwell) is selected with the air distribution selector wheel in the heating and air conditioning system control panel.

    The microswitch records the current position of the cam disc and thus the position of the air distribution flap motor.

Differences between the heating and air conditioning systems (E8x, E9x):

IHR IHKR , integrated automatic heating/air conditioning system
Interior temperature sensor --- --- 1
Solar sensor --- --- 1
Condensation sensor --- --- 1
Automatic air recirculation control sensor --- --- 1
Evaporator temperature sensor --- 1 1
Refrigerant pressure sensor --- 1 1
Defroster flap motor --- --- 1
Air distribution flap motor 1 1 ---
Ventilation flap motor --- --- 1
Footwell flap motor --- --- 1
Mixing flap drive 1 1 2
Evaporator --- 1 1
Air conditioning compressor --- 1 1
Stratification control (E9x) --- --- 1
Front stratification-flap motor (E9x; E84, from 09/2007 also E8x) --- --- 1
Rear stratification control (E9x only) --- --- 1
Rear-compartment stratification flap motor (E9x only) --- --- 1

Integrated automatic heating / air conditioning (IHKA) in the E7x

The IHKA in the X5 is a water-controlled heating and air-conditioning system.

The X5 is equipped with the integrated automatic heating and air-conditioning system in the basic version as standard (IHKA Basis). The Basic version does not provide for separate settings for the driver's and the passenger's sides.

The integrated automatic heating and air conditioning system in High version (IHKA High) with left-right separation for the driver's side and passenger's sides is optional (SA534).

The automatic rear air-conditioning system (FKA) is optional equipment (SA4NB).

An auxiliary heating/ventilation system is available as optional equipment for the 3rd row seats (SA4NC).

New features on IHKA High:

  • Integrated automatic heating and air-conditioning system (IHKA) High with automatic rear air-conditioning system (FKA)

    In addition to the separate settings for the driver's and passenger's sides, separate settings are also possible for the left and right sides in the rear seats (option SA4NB).

    The rear seat passengers can set the temperature and blower speed separately for the left and right sides on the FKA control panel.

  • Rain/light solar sensor (IHKA High only)

    The solar sensor is a component of the rain‐light solar sensor (RLSS).

Differences between the heating and air-conditioning systems (E7x):

IHKA Basic IHKA High with left/right separation IHKA High with rear automatic air conditioning (FKA)
* actuated by FKA control unit
Solar sensor --- 1 1
Condensation sensor --- 1 1
Automatic air recirculation control sensor --- 1 1
Ventilation temperature sensor, front 1 2 2
Ventilation temperature sensor, rear passenger compartment --- --- 2*
Footwell temperature sensor, rear passenger compartment --- --- 2*
Heating heat exchanger sensor 1 2 2
Footwell flap motor, front 1 2 2
Footwell flap motor, rear --- --- 2
Ventilation flap motor, front 1 2 2
Ventilation flap motor, rear passenger compartment --- 1 2
Front stratification-flap motor 1 2 2
Rear stratification controller --- 1 2*
Heating element (PTC principle) in rear passenger compartment left footwell ventilation duct --- --- 1*
Heating element (PTC principle) in rear passenger compartment right footwell ventilation duct --- --- 1*
Brief component description

Control unit:

  • IHR, IHKR and IHKA control panel/control unit

    The control panel and control unit together form a single component. There are different versions for integrated heating control, integrated heating/air-conditioning control and IHKA.

    >E8x, E9x: control panel/control unit [more ...]

    From 09/2009, the IHKA version with SA494 "seat heating for driver and front passenger", the two seat-heating switches are integrated in the control panel for the automatic heating and air conditioning system.

    >E7x: control panel/control unit [more ...]

  • Control panel/control unit for automatic rear air-conditioning system, E7x only

    The automatic rear air-conditioning system (FKA) is available in the X5 as additional equipment with the IHKA. The FKA controls the rear air-conditioning system/heating.

    [more ...]

Sensors:

  • Interior temperature sensor (only IHKA)

    The force-ventilated interior temperature sensor with interior temperature sensor blower is fitted in the IHKA control panel. The interior temperature sensor measures the air temperature drawn in from the passenger compartment by the integrated interior temperature sensor blower.

    Substitute value for the sensor: 20 °C

    >E8x, E9x

    From 09/2009, the IHKA version with SA494 "seat heating for driver and front passenger" no longer includes the forced ventilation for the interior temperature sensor.

    >E7x

    The separate settings for the left and right sides in the rear passenger compartment mean that the rear heating and air-conditioning control panel has an automatically ventilated interior temperature sensor.

  • Solar sensor (only IHKA)

    The solar sensor consists of a photosensor (E7x: 2 photosensors) and detects external sources of light and/or heat (e.g. radiation of the sun) that influence the climate in the passenger compartment.

    Sunlight compensation is only active in the automatic program.

    > E8x, E9x only IHKA

    The solar sensor supplies the IHKA control unit with an analogue signal that depend on the intensity of the sunlight.

    The solar sensor is clipped into the middle of the dashboard.

    > E7x (only integrated automatic heating and air-conditioning system in High version)

    The solar sensor is a component of the rain‐light solar sensor (RLSS). The RLSS measures external sources of light and heat (e.g. sunlight) for left and right sides of the vehicle. The sensor data are processed in the evaluation electronics of the rain/light solar sensor. Signal path: RLSS -> LIN bus -> FZD (roof function centre; operates as a data interface) -> IHKA control unit

    The rain/light solar sensor is attached to the inside of the windscreen within the wiper range of the windscreen wipers.

  • Sensor for automatic air recirculation control

    > E8x, E9x only IHKA

    > E7x (only integrated automatic heating and air-conditioning system in High version)

    The AUC sensor is fitted on the microfilter compartment. The AUC sensor detects the following pollutant emissions from spark-ignition and diesel engines:

    • Hydrocarbons (CH )
    • carbon monoxide (CO)
    • Nitrogen oxides (nitrogen monoxide NO, nitrogen dioxide NO2)

    The junction box supplies the AUC sensor with voltage. The junction box electronics evaluate the data of the AUC sensor. The junction box electronics unit transmits relevant data to the IHKA control panel (via the K‐CAN).

  • Condensation sensor (only IHKA)

    > E8x, E9x only IHKA

    > E7x (only integrated automatic heating and air-conditioning system in High version)

    The condensation sensor measures the air humidity on the windscreen in the passenger compartment. The condensation sensor is able to detect condensation on the windscreen before it becomes visible. The condensation sensor draws its power supply from the roof control panel. The FZD evaluates the condensation sensor data. The FZD sends appropriate data to the IHKA control unit (via the K‐CAN). Measures to avoid condensation on the window surfaces are only initiated in automatic program.

    [more ...]

  • Evaporator temperature sensor (IHKR, IHKA only)

    The evaporator temperature sensor measures the outlet temperature of the air at the evaporator to prevent icing from occurring. The evaporator temperature sensor is directly connected to the control unit for the heating and air conditioning system.

    Substitute value for the sensor: -2 deg C

  • Ventilation temperature sensor

    A sensor is integrated into the heating and air-conditioning unit to measure the ventilation temperature. The ventilation temperature sensor measures the delivery temperature directly at the centre ventilating flap on the driver's side. The ventilation temperature sensor is directly connected to the control unit for the heating and air conditioning system.

    >E7x

    If the IHKA High is fitted, there are 2 ventilation sensors (on the ventilation flaps for the driver's and the passenger's sides).

    Substitute value for the sensor: 20 °C

    > E7x with automatic rear air-conditioning system

    One sensor is fitted at each of the left and right rear air outlets in the centre console.

  • Footwell temperature sensor

    >E8x, E9x

    A sensor is integrated into the heating and air-conditioning unit to measure the footwell temperature. The footwell temperature sensor measures the blow-out temperature directly at the footwell flap on the driver's side. The footwell temperature sensor is directly connected to the control unit for the heating and air conditioning system.

    Substitute value for the sensor: 20 °C

    > E7x with automatic rear air-conditioning system

    One sensor is attached to each of the left and right footwell air outlet in the rear compartment.

  • Sensor for heating system heat exchanger

    >E7x

    The sensor is integrated in the heating and air conditioning system. On the IHKA Basic, the sensor measures the blow-out temperature on the drivers side, directly on the delivery side of the heating system heat exchanger. On the IHKA High, 2 sensors are installed as the blow-out temperatures are measured separately at the heating system heat exchanger for the driver's and the passenger's sides. The heat exchange sensor is directly connected to the control unit for the heating and air conditioning system.

    Substitute value for the sensor: 55 °C

  • Refrigerant pressure sensor (IHKR, IHKA only)

    The refrigerant pressure sensor is located in the pressure line between the capacitor and the evaporator. Depending on the sensor signal, the air conditioning compressor is regulated by the control unit for the heating and air conditioning system in the event of excessive refrigerant pressure.

    The junction box supplies the refrigerant pressure sensor with voltage. The data is evaluated in the junction box electronics. The prepared data is sent across the body CAN (K‐CAN) to the control unit for the heating and air conditioning system.

Actuators:

  • Electric auxiliary heater (only vehicles with diesel engine)

    The electric auxiliary heater works on the principle of PTC (positive temperature coefficient) and is installed in the heating and air-conditioning unit. The electric auxiliary heater directly heats up the air to adjust the temperature of the passenger compartment.

    [more ...]

  • Flap motors

    The flap motors are controlled by the heating and air conditioning system control panel/control unit via the LIN bus.

    >E8x

    • IHR/IHKR

      The IHR/IHKR has 3 flap motors.

    • IHKA until 09/2007

      The IHKA has 6 flap motors (due to the left/right separation for the driver's and the passenger's sides and because there are no central kinematics).

    • IHKA from 09/2007

      7 flap motors are installed in the IHKA (the front stratification-flap motor is new).

    > E84

    • IHKR

      The IHKR has 3 flap motors.

    • IHKA

      The IHKA has 7 flap motors (due to the left/right separation for the driver's side and the passenger's side, the additional stratification flap motors and because there are no central kinematics).

      A rear-compartment stratification flap motor is not available!

    >E9x

    • IHKR

      The IHKR has 3 flap motors.

    • IHKA

      The IHKA has 8 flap motors (due to the left/right separation for the driver's side and the passenger's side, the additional stratification flap motors and because there are no central kinematics).

    >E7x

    • IHKA Basic

      The IHKA Basic has 6 flap motors.

    • IHKA High

      The IHKA High has 10 flap motors (due to the left/right separation for the driver's and the passenger's sides and the ventilation flap motors for the rear compartment).

    • IHKA High with automatic rear air-conditioning system

      With the IHKA High with automatic rear air-conditioning system (FKA), there are 13 flap motors (due to the separate settings for the driver's and passenger's sides in the front and rear).

  • Central kinematics (IHR, IHKR only)

    The central kinematics are used to mechanically adjust the air distribution flaps. The central kinematics are driven by the air distribution flap motor. The control unit of the heating and air conditioning system activates the air distribution flap motor.

  • Blower with blower output stage

    The blower creates the necessary air mass flow. The blower is fitted after the fresh air/recirculated air flap in the heater/air conditioning system (pressing blower arrangement). The blower output stage is mounted directly at the housing of the blower motor. The blower output stage is actuated with a pulse-width modulated signal (PWM signal) by the heating and air conditioning control unit. The blower output stage is not diagnosis-capable.

  • A/C compressor with electric control valve (IHKR, IHKA only)

    The air conditioning compressor compresses the refrigerant taken in by the evaporator. The refrigerant is pressed towards the capacitor. The A/C compressor used is clutch-free. That means that the A/C compressor always runs with the engine. A swash plate in the A/C compressor allows the output to be smoothly regulated. The electric control valve on the A/C compressor influences the balance of forces on the swash plate and thus the adjustment of the displacement. For the purpose of load reduction, only the cooling power that is directly needed is generated.

    The junction box electronics unit controls the control valve with a clocked voltage.

Note: A/C compressor with magnetic coupling

Measures to reduce CO2 emissions: Depending on the engine version and national-market version, an A/C compressor with magnetic coupling supersedes the A/C compressor previously installed with electric control valve.

  • Evaporator (IHKR, IHKA only)

    The evaporator fins are cooled by the refrigerant that has been evaporated inside the evaporator. The air mass flow generated by the blower is fed over the cooled evaporator fins. The air is cooled and dried and fed into the vehicle.

  • Auxiliary water pump

    The additional coolant pump serves to make sure that the coolant flow rate needed in the heater circuit is maintained, even at low engine speeds. The auxiliary coolant pump is actuated by the junction box, from which it also draws its voltage supply. The heating and air conditioning system control unit emits the signal for switching the auxiliary coolant pump on/off (via the K‐CAN).

  • Water valve

    >E7x

    The water valve operates electromagnetically and meters the coolant flow rate to the heating system heat exchanger as it is needed. This regulates the air temperature for heating the passenger compartment (heating and air conditioning that regulates water temperature).

    On the IHKA High, a dual water valve is used for the left/right separation of the heating system heat exchanger. The junction box electronics (JBE) actuates the water valve.

  • Radiator fan

    The radiator fan and the engine cooling are also required for cooling the condenser. The engine control unit activates the radiator fan.

    Signal path:

    Control unit for air conditioning -> body CAN -> JBE (operates as data interface) -> PT-CAN -> engine control unit -> radiator fan

  • Condenser with integrated dryer flask (IHKR, IHKA only)

    In the capacitor, gaseous refrigerant is converted into liquid refrigerant. In the integrated downstream dryer flask, any water present in the refrigerant circuit is bound. The desiccant insert can be exchanged.

  • Expansion valve (IHKR, IHKA only)

    The expansion valve controls the injection quantity into the evaporator. Only as much liquid refrigerant enters the evaporator as the evaporator is able to completely evaporate. Drops of liquid that have not been evaporated would cause damage in the A/C compressor. The expansion valve is fitted directly to the engine bulkhead.

Additional components:

  • Microfilter

    Fresh air for interior ventilation is fed through a microfilter.

    >E8x, E9x: IHR, IHKR

    When a filter renewal is needed, this will be indicated by the Condition Based Service (CBS) (until 03/2007).

    from 03/2007: Filter renewal: see Service Booklet

    >E7x: IHKA

    Filter renewal: see Service Booklet

  • Microfilter with activated carbon

    A microfilter with activated carbon is built into the IHKA. The carbon canister makes an additional contribution to cleaning the fresh air that enters of gaseous pollutant emissions.

    >E8x, E9x: IHKA

    When a filter renewal is needed, this will be indicated by the Condition Based Service (CBS) (until 03/2007).

    from 03/2007: Filter renewal: see Service Booklet

    >E7x: IHKA

    Filter renewal: see Service Booklet

  • Stratification control and rear stratification control

    > E7x integrated automatic heating and air-conditioning system in High version and E9x IHKA

    The selected potentiometer setting is transposed into the flap position of the specific flap motor (front and rear stratification flap motor and rear ventilation flap motor).

    > E7x integrated automatic heating and air-conditioning system in High version with automatic rear air-conditioning system

    Due to the separate settings for the left and right sides in the rear, there are 2 rear stratification controls and 2 ventilation flap motors in the rear.

  • local interconnect network bus

    A data line supplies all component on the LIN bus with the necessary control information. This data line also carries the status reports of the components back to the heating and air conditioning system control unit. The control unit controls the following components via the LIN bus:

    • Electric auxiliary heater
    • Flap motors

The following control units are involved in the functions of the heating and air conditioning system:

  • SZM: Centre console control panel

    A 14-pin plug connects the SZM with the control unit for the heating and air conditioning system. The heating and air conditioning control unit serves as the interface between the SZM and the K‐CAN.

    The control unit for the heating and air conditioning system handles the following tasks for the SZM:

    • Reading off settings made by pressing buttons
    • Activating LEDs for function indicator lighting
    • Dimming LEDs for function and locator lighting
    • Forwarding relevant CAN messages
  • JBE: Junction Box Electronics

    The JBE is the data interface (= gateway) between the K‐CAN and the PT‐CAN. (K CAN = body controller area network; PT CAN = powertrain controller area network.)

    The JBE receives input signals from some of the sensors and control units (e.g. AUC sensor, engine control unit, heating and air conditioning system control unit).

    The junction box consists of the JBE and the power distribution box. Amongst other things, the power distribution box supplies power to the heated rear window. The JBE activates the heated rear window.

  • M‐ASK or CCC or CHAMP: Multi‐audio system controller or Car Communication Computer or multimedia platform

    The controller signals for selecting the menu are processed in the M‐ASK or CCC or CHAMP (multimedia platform: CHAMP; Central Head Unit and Multimedia Platform).

    To actuate the CID (Central Information Display), the red-green-blue signals from the graphics processor are converted into digital signals.

  • CAS: Car Access System

    The CAS comprises the master key functions, amongst other things.

    The CAS assigns a personalisation number to every master key. The CAS transfers the personalisation number to the IHKA control unit via the K‐CAN.

    Key-based settings (Key Memory) are stored in the IHKA control unit.

    When the vehicle is unlocked, the master key unit used is recognised. The settings stored for this unit are called up and executed. In the after-running period, the current settings are stored for the master key unit in use at that time.

  • DME or DDE: Digital Motor Electronics and/or Digital Diesel Electronics

    The engine control unit (DME and/or DDE) actuates the radiator fan.

    On vehicles with diesel engine, the DDE provides the electric auxiliary heater with information about the maximum electrical power available (with a pulse-width modulated signal). The maximum electrical power available depends on the load on the alternator.

  • Control and display functions via controller and Central Information Display (IHKA only)

    The following control and display functions are selected and activated with the controller in the CID (Central Information Display):

    • Air distribution

      The defroster flaps, ventilation flaps and footwell flaps can be individually set in the air distribution submenu.

    • Automatic mode

      The intensity of the IHKA can be set in the automatic program submenu. That means: The automatic influence of the climate conditions outside the vehicle on the air mass and the opening angle of the flaps can be set to one of three different settings (low, medium, high).

      > E7x with integrated automatic heating and air-conditioning system in High version

      The settings can be selected and activated on the IHKA control panel.

    • Automatic rear air-conditioning system

      > E7x with integrated automatic heating and air-conditioning system in High version

      The automatic rear air-conditioning system can be activated or deactivated in the ”Automatic program” submenu.

      The function "Use driver's settings" can be selected to adopt the (driver's) settings from the IHKA control panel for the FKA control panel.

System functions
The heating and air conditioning system incorporates the following functions:
  • Temperature control
  • Evaporator control (IHKR/IHKA only)
  • Air distribution
  • Air flow control
  • Sunlight adaptation (solar sensor)
  • MAX cooling (IHKA only)
  • Residual heat (IHKA only)
  • ALL function (only IHKA E8x, E9)
  • Defrost function (IHKA only)
  • AUTO function (IHKA only)
  • Rear window heating
  • OFF
  • Air recirculation function
  • Automatic air recirculation control (IHKA only)
  • Program for preventing condensation on the window surfaces (IHKA only)
  • Central kinematics actuation (IHR, IHKR only)
  • Convertible program (E93 only)
  • Auxiliary heater operation (optional equipment 536)
  • Automatic rear air-conditioning system (SA4NB, E7x only)
  • Auxiliary heating/ventilation for 3rd row seats (SA4NC, E7x only)
  • Seat heating (E8x and E9x from 09/2009, E7x) and active seat heating (E7x only)
  • Steering wheel heating
  • Steering column adjustment
Temperature control
  • E8x, E9x: Air-controlled heating and air conditioning systems

    The temperature for the best possible interior climate is regulated with a blending flap in the heating and air-conditioning unit.

    The air mass flow is fed through the evaporator (IHKR, IHKA only). As this happens, the air mass flow is cooled and dried (providing the air-conditioning system is switched on). The blending flap then feeds the air mass flow completely or in part over the heating system heat exchanger and the electric auxiliary heater (depending on the desired nominal temperature value set at the control panel). Subsequently, the air flows mix once again. The air mass flow is then fed through the ventilation flaps and into the passenger compartment. On the IHKA, the air ducts for the driver and front passenger are separate. Due to the separate settings for the left and right sides on the driver's and the passenger's side there are 2 mixing flaps.

    • IHR, IHKR

      Temperature control is based on the setpoint value set and a calculated actual value The setpoint value is set at the temperature selector wheel on the heating and air conditioning system control panel. The actual value is calculated from the temperatures measured by the ventilation temperature sensor and the footwell temperature sensor.

      With the IHR, temperature control below the ambient temperature is not possible.

    • IHKA

      Control is based on the setpoint values set and the calculated actual value The setpoint values are set using 2 temperature selector wheels on the heating and air conditioning system control panel (separate settings for left and right sides). The actual value is calculated from the temperatures measured by the ventilation temperature sensor and the footwell temperature sensor.

      The reference variable is calculated from the comparison between the actual value for the interior temperature and the corrected setpoint value (calculated from customer request and ambient temperature). Compared to the set setpoint value, the interior temperature is raised in the cold so that a comfortable level is achieved even at negative temperatures, despite the temperature setting being unchanged. The ambient temperature is transmitted to the IHKA control unit via the body CAN (body Controller Area Network).

  • E7x: Water-controlled heating and air conditioning systems

    Within the heating/air-conditioning systems, the air mass flow is first fed through the evaporator. As this happens, the air mass flow is cooled and dried (providing the air-conditioning system is switched on). The air mass flow is then fed over the heating system heat exchanger and the electric auxiliary heater,where it is heated up to the required setpoint value (depending on the desired temperature value set on the IHKA control panel). The air mass flow is then guided via the air flaps into the passenger compartment.

    The IHKA High has separate air ducts for the driver and front passenger. The separate settings for the driver's and the passenger's sides means that the heating system heat exchanger also has separate settings for the left and right sides.

    • IHKA Basic

      The temperature in the heating system heat exchanger is controlled with the help of the heating system heat exchanger sensor and a clocked water valve in the heater circuit. The water valve is actuated with a pulse-modulated signal (PWM signal) by the IHKA control unit. A characteristic map for the heating system heat exchanger determines the opening times for the water valve, depending on the engine speed.

      Control is based on the setpoint value set by the vehicle occupants at the temperature selector wheel and the calculated actual value. The setpoint values are set via a temperature selector wheel on the IHKA control panel.

      The actual value is calculated from the temperatures measured by the interior temperature sensor, the ventilation temperature sensor and the heating system heat exchanger sensor.

      The reference variable is calculated from the comparison between the actual value for the interior temperature and the corrected setpoint value (calculated from customer request and ambient temperature). Compared to the set setpoint value, the interior temperature is raised in the cold so that a comfortable level is achieved even at negative temperatures, despite the temperature setting being unchanged.

      The ambient temperature is transmitted to the IHKA control unit via the body CAN (body Controller Area Network).

    • IHKA High

      The separate temperature setting for the driver's and the passenger's sides affects:

      - Heating system heat exchanger with left/right separation

      - 2 heating system heat exchanger sensors

      - 2 ventilation temperature sensors

      - Dual water valve

Evaporator control (IHKR, IHKA only)

The evaporator temperature is regulated with the help of the evaporator temperature sensor and the expansion valve. The evaporator temperature is adjusted to the specified setpoint value of 2 C. Lower temperatures are not possible due to the risk of icing.

If the ”variable evaporator control” function has been encoded, the setpoint evaporator temperature is calculated between 2 and 7 C. The specification depends on the ambient temperature, the ventilation temperature and the refrigerant pressure. A variable evaporator control reduces dehumidification. This reduces the risk of mucous membranes drying out.

Air distribution setting

For the best possible operation of the air distribution, it is important for the manually adjustable air vents to be open.

  • IHR, IHKR

    Air distribution selection is only possible manually with the air-distribution control wheel.

  • IHKA

    Occupants have the possibility of allowing the air distribution to be decided by the automatic program (AUTO button).

    Alternatively, individual, personal air distribution is possible through manual selection (defrosting, ventilation, footwell).

    If the relevant vehicle equipment is fitted to the vehicle, it is also possible to make a fine adjustment via the CID (Central Information Display) in the submenu Air distribution. Compared to manual selection, fine adjustment offers the additional possibility of further individualisation of the air distribution.

    >E7x: IHKA Basic

    With the IHKA Basic, the air distribution can only be set manually with the controller.

    The menu provides the following settings:

    • 4 different pre-adjustments and

      one individually configured setting

    The vehicle occupants can effect individual air distribution/stratification of hot and cold air inside the vehicle at the same temperature setting.

    >E7x: IHKA High

    In addition, air distribution can also be set on the IHKA control panel.

    The menu provides the following settings:

    • Driver's side:

      4 different pre-adjustments and

      one individually configured setting

    • Passenger's side:

      3 different pre-adjustments and

      one individually configured setting

    Settings for ventilation temperature (stratified temperatures) can also be made in this menu. With the IHKA High, separate stratification can be set for the left and right sides in the front. Stratification is also possible in the rear.

    >E7x: IHKA High with automatic rear air-conditioning system

    With the IHKA High with automatic rear air-conditioning system, stratification can be set separately for the left and right sides in the rear.

Air flow control

The air flow control is dependent on the following settings and control actions:

  • Manual blower setting
  • Automatic blower and flap setting (IHKA only)

    The automatic blower and flap functions are activated when the AUTO button is pressed.

  • Ram air pressure compensation

    The air mass at the air intake grilles increases disproportionately with increasing driving speed. This effect is compensated for by the opening angle of the fresh air flap being reduced as speed increases (ram air pressure compensation).

    The opening angle is controlled according to a defined characteristic curve.

  • Blower control

    If necessary, the power management system will assign priority levels to reduce the blower output (via K‐CAN).

  • Effect of terminal 50

    When the engine is being started (terminal 50 ON), the electric auxiliary heater and blower are switched OFF to reduce the load on the car battery.

Sunlight adaptation (solar sensor)

> E7x integrated automatic heating and air-conditioning system in High version and E8xE9x IHKA

The following functions are modified when automatic mode is activated (depending on the intensity of sunlight):

  • Blower output is increased or reduced
  • Nominal temperature value is increased or reduced

> E7x High

The influence on IHKA control by the solar sensor is assigned separately to the driver's and the passenger's side.

> E8x, E9x IHKA

How the solar sensor affects the IHKA control on the driver's side and the passenger's side is not programmed separately.

MAX cooling (IHKA only)

The MAX button makes it possible for the user to select maximum cooling with just one press of a button on the IHKA control panel.

When the MAX button is pressed, all functions, including the defrost function, are deactivated. The air-conditioning function is activated (if it was not already activated) and defined settings are selected (e.g. temperature control is deactivated, ventilation flaps are fully opened).

Residual heat (IHKA only)

The residual heat function allows the waste heat from the engine to be used to heat up the passenger compartment when the engine is not running (e.g. during a stop at a level crossing). The residual heat function is only possible for a certain run-down period (15 minutes from terminal 15 OFF). The additional coolant pump is activated to circulate the water.

Switch-on conditions:

  • Terminal 15 OFF

    and

  • Run-down period active (up to 15 minutes after terminal 15 OFF)

    and

  • REST button* in IHKA control panel  ON

    and

  • Ambient temperature below 25 C

    and

  • Engine temperature at some point above 60 C

    and

  • Vehicle voltage over 11.4 volts

Condition for switch-off condition:

  • Terminal 15 ON

    or

  • Residual heat ON (15 minutes) expired

    or

  • REST button* in IHKA control panel OFF

    or

  • OFF condition activated with residual heat active (terminal R)

    or

  • Prompt from power management to switch off auxiliary consumers

    or

  • Vehicle voltage less than 11 volts

* The residual heat button is omitted in the X5. The function of the REST button is integrated into the blower speed button.

From 09/2009, the REST button will be discontinued for E8x, E9x. The REST button will be replaced with the ALL button.

ALL function (IHKA E8x, E9x from 09/2009 only)

One keystroke on the ALL button is used to transfer the current setting for the driver's side (temperature, amount of air and air distribution) to the passenger's side.

Defrost function (IHKA only)

When the defrost function is activated, the defroster flap (on the inside in front of the windscreen) is opened fully. The fresh air/recirculated air flaps move to the ”fresh air” position. All other flaps are closed. The blower is run up to maximum output.

> E7x with automatic rear air-conditioning system

The blower in the rear is switched off.

AUTO function (IHKA only)

When this button is pressed, all IHKA functions are set to automatic mode. If one or more automatically controlled functions are manually set, automatic control for the functions concerned will be cancelled. All other functions remain automatically controlled.

Heated rear window

The heated rear window is switched on by pressing the button in the control panel of the heating and air conditioning unit. The function indicator light in the button lights up.

The heated rear window is switched off by pressing the button again or automatically after the heating period has elapsed.

>E8x

  • Defrosting phase (1st heating period)

    When terminal 15 is switched ON, the first time the system is switched on, the time span for the heated rear window is defined as follows:

    Ambient temperature down to ‐-15 °C: heating period: 20 minutes

    Ambient temperature below -15 °C: heating period: 30 minutes

  • Pulsing

    After the defrosting phase, the heating phase (30 minutes with pulsed heat output (on-off cycle: 40 seconds ON, then 80 seconds OFF).

    The function indicator light in the button is off during pulsing.

  • 2nd heating period

    After the 1st heating period has expired, each subsequent time the button is pressed will cause the heated rear window to be switched on for a further 30 minutes (defrosting phase).

    After the 2nd heating period has expired, output is again pulsed.

>E7x, E9x

  • Defrosting phase (1st heating period)

    When terminal 15 is switched ON, the first time the system is switched on, the time span for the heated rear window is defined as follows:

    Ambient temperature down to ‐-15 °C: heating period 10 minutes

    Ambient temperature below -15 °C: heating period 17 minutes

  • Pulsing

    After the defrosting phase, the heating phase (25 minutes with pulsed heat output (on-off cycle: 40 seconds ON, then 80 seconds OFF).

    The function indicator light in the button is off during pulsing.

  • 2nd heating period

    After the 1st heating period has expired, each subsequent time the button is pressed will cause the heated rear window to be switched on for a further 30 minutes (defrosting phase).

    After the 2nd heating period has expired, output is again pulsed.

OFF

The heating and air conditioning system control panel is switched off when the blower speed is set to 0 (The control panel/control unit continues to run in the background.)

Air recirculation function

In the recirculated air mode, in the event of a high pollutant load, e.g. in a traffic jam, the supply of fresh air can be blocked. The air in the passenger compartment is permanently recirculated. To guarantee a sufficient fresh air supply, the air recirculation function is limited to a certain duration (30 minutes air recirculation function -> 30 seconds partial fresh-air mode -> 30 minutes air recirculation function -> etc.).

Automatic air recirculation control

> E8x, E9x only IHKA

> E7x only integrated automatic heating and air-conditioning system in High version

If the AUC sensor detects an increased level of pollutants in the environment from spark-ignition and diesel engines, the IHKA control unit will automatically switch to air-recirculation mode.

To ensure adequate fresh-air supply, the recirculated air mode has a time limit:

  • at ambient temperatures below 0 C:

    2 minutes air recirculation function -> 1 minute fresh air mode (from 03/2005: 20 seconds) -> 2 minutes air recirculation function -> etc.

  • at ambient temperatures of 0 C to 6 C:

    3 minutes air recirculation function -> 1 minute fresh air mode (from 03/2005: 20 seconds) -> 3 minutes air recirculation function -> etc.

  • during operation without air conditioning function at ambient temperatures above 6 C:

    4 minutes air recirculation function -> 1 minute fresh air mode (from 03/2005: 20 seconds) -> 4 minutes air recirculation function -> etc.

  • during operation with air conditioning function at ambient temperatures above 6 C:

    12 minutes air recirculation function -> 1 minute fresh air mode (from 03/2005: 20 seconds) -> 12 minutes air recirculation function -> etc.

When the engine is started and the AUC function activated, fresh-air mode is always selected for approx. 40 seconds due to the warming phase of the AUC sensor.

Program for preventing condensation on the window surfaces (IHKA only)

The following conditions must be satisfied for measures against condensation on the windscreen to be effected:

  • Engine running

    and

  • The IHKA must be in automatic program

The IHKA control unit evaluates condensation sensor signal (air humidity). If condensation on the windscreen is imminent, the following measures are initiated in sequence to prevent condensation from forming.

If a measure proves to be ineffective, the next measure is initiated.

Once successful, the measures previously performed are reversed step-by-step in reverse order.

Measures if the windscreen threatens to mist over:

  • Open defroster flaps further
  • Switch from air recirculation function/AUC/automatic air recirculation function

    to partial fresh-air mode

  • Switch from partial fresh-air mode in air recirculation function/AUC/automatic air recirculation function to fresh air
  • Increase air mass with the blower
  • Reduce air mass for the footwell
  • Increase nominal temperature value

Central kinematics actuation (IHR, IHKR only)

The air distribution flap motor has the task of setting the air distribution over a cam disc. The air distribution flap motor has no way of recognising the actual position. To allow the cam disc to be unambiguously positioned despite this, there are two cams of different widths on the cam disc. The microswitch signals to the heating and air conditioning system control unit that the cams have been passed over. This mechanism achieves reliable and rapid positioning of the cam disk.

Convertible program (only E93)

The convertible program is activated in the factory. (this factory setting can be deactivated in the ”Personal Profile”.)

Switch-on conditions:

  • Terminal 15 ON
  • Soft top open

The convertible program comprises the following functions:

  • The condensation sensor is switched off
  • The blower speed increases with increasing driving speed
  • Air distribution is switched to the upper body and head, airflow to the footwell is throttled.
  • Ram air pressure compensation is changed, i.e. as driving speed increases, the air mass fed into the vehicle through the fresh air grille increases.
  • Solar sensor control variables are changed

    When the soft top is open, the solar sensor evaluates the ambient brightness (darkness to intense sunshine) more strongly. For this reason, the solar sensor has a stronger effect on the IHKA controls when the soft top is open.

In the convertible program, the blower speed can be changed manually on the IHKA control panel. The automatic flap control remains active (no change to flap position).

If the convertible program is active and the flap positions are changed with the CID (Central Information Display) and controller, the convertible program will be deactivated. This means that manual settings will be assumed, unchanged settings will revert to those that the air-conditioning system had before the soft top was closed.

The convertible program can be completely reactivated by pressing the AUTO button.

Auxiliary heater operation (optional equipment 536)

The auxiliary heater operation is activated either via the Central Information Display (CID) or via Telestart (through the Car Access System (CAS)). There are 2 ways of switching the system on via the CID:

Direct operation or programming using the timer.

[for more information, please refer to SI Technology (SBT) 64 01 05 135]

Automatic rear air-conditioning system (SA4NB, only E7x)

The automatic rear air-conditioning system provides for separate temperature and blower settings for the left and right sides in the 2nd row of seats.

[more ...]

Auxiliary heating/ventilation for 3rd row seats (SA4NC, E7x only)

A rear compartment blower suctions the air under the seats of the 3rd row seats. The rear compartment blower blows the air out through the ventilation outlets between the seats of the 3rd row seats.

[more ...]

Seat heating (E8x and E9x from 09/2009, E7x) and active seat heating (E7x only)

Seat heating and active seat ventilation in front

If the seat heating/active seat ventilation button is pressed, the IHKA control unit sends the status as a K‐CAN message.

Depending on the equipment specification of the seat, the message is received either by the seat modules or by the Junction Box electronics (JBE).

  • Message direct to the seat modules:

    The seat heating and the active seat ventilation are actuated by the respective seat module according to the operating logic at the IHKA control panel.

  • Message via Junction Box electronics:

    The Junction Box electronics transmits a message to the seat modules in the form of a pulse-width modulated signal (PWM signal). The seat heating is actuated by the respective seat module according to the operating logic at the IHKA control panel.

If the energy management system requires a reduction in output, the heater and blower output may be reduced in 3 stages or switched off completely:

  1. Heating and blower output are reduced from level 3 to level 2
  2. Heating and blower output are reduced to 50 percent of level 2
  3. Seat heating and active seat ventilation are switched off

Seat heating in rear without automatic rear air-conditioning system

When the seat-heating switch for the rear is pressed (2 levels), the seat heating is directly actuated.

If the energy management system requires a reduction in output, the seat heating in the rear may be switched off by a relief relay.

Seat heating in rear with automatic rear air-conditioning system

The seat-heating switches are located in the FKA control panel.

The status of each seat-heating switch is transmitted to the respective seat module (rear driver's side seat and rear passenger's side seat) by means of a pulse-width modulated signal (PWM signal). If the energy management system requires a reduction in output, the heater output may be reduced in 3 stages or switched off completely.

Steering wheel heating (E7x only)

The steering wheel heating is integrated in the steering column switch cluster (SZL). The IHKA control unit transmits the signal for the steering wheel heating to be switched off (power‐down command).

Electrical steering column adjustment (E7x only)

The electrical steering column adjustment enables the driver to set the optimised position of the steering wheel. There is a switch on the left of the steering column for operation. The inclination and length of the steering column are adjusted electrically. Power for the electrical steering column adjustment is provided via terminal 30 switched.

The IHKA control unit actuates the electric steering column adjustment. When the steering column is adjusted, a hall effect sensor on the steering column adjustment motor sends a signal the IHKA control unit. The position of the steering column is registered and stored by the IHKA control unit.

For the key memory, this means that the position of the steering column can be called up. To support entry and exit, the tilt adjustment moves to the highest position.

For Easy Exit, the steering column adjustment is automatically activated under the following conditions:

  • Terminal R OFF
  • Terminal R ON and driver's door is opened (signal via door contact)
  • Terminal 15 OFF with driver's door open (signal via door contact)

The steering column memory is activated under the following conditions:

  • One of the two memory buttons is pressed (from terminal R ON).
  • Another identification sensor is used (personalisation). Precondition: The selection ”Last seat position after unlocking” is activated in the ”Settings” menu in the Central Information Display (CID).

In both cases, the steering column memory only moves to the corresponding memory position after terminal 15 On.

Notes for Service department
Observe the following information for service:
National-market version

Temperature display in °C (Celsius) or °F (Fahrenheit) can be selected with an on-board computer function.

We can assume no liability for printing errors or inaccuracies in this document and reserve the right to introduce technical modifications at any time.

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