BMW E46 User manual

Initial Print Date:10/30/00 Revision Date:12/05/00
Subject Page
E46 IHKA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Control Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Fresh Air Micro Filter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Te perature Regulation - Heating. . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Te perature Regulation - Cooling. . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Co pressor Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Stepper Motor M-Bus Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Convertible Rear Window Defroster. . . . . . . . . . . . . . . . . . . . . . . . . . 10
IHKA Personalization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Syste Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Diagnosis and Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
E46 IHKA I.P.O. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Solar Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Purpose of the Syste .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Solar Radiation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Solar Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Co ponents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Syste Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Table of Contents
E46 CLIMATE CONTROL

Subject Page
Control Curves
Blower Intervention. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Te perature Intervention. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Ventilation Intervention. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Diagnosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Workshop Hints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
E46 IHKR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Purpose of the Syste . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Syste Co ponents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
IHKR I.P.O. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
IHKR Control Unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
IHKR Housing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Principle of operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Blower adjust ent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Air Distribution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Te perature Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Engine Map Cooling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
Service Station Feature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Air Conditioning Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Air Intake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Ra Effect Air Co pensation. . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Rear Window Defroster. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Workshop Hints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Re iew Questions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

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E46 Cli ate Control
E46 IHKA
Model: E46
Production Date: From 6/98
Objecti es
After co pleting this odule you should be able to:
• Know how to replace the Fresh Air Micro Filter.
• Describe the cli ate control functions perfor ed by the IHKA control unit.
• Explain the co pressor activation circuit.
• Recognize Car and Key Me ory progra ing possibilities.

E46 IHKA Climate Control
The IHKA heater/air conditioner in the E46 is si ilar to the syste previously installed in the
E36. Design and co ponent changes were ade to i prove the overall perfor ance and
operation of the syste . This odule will deal with the changes and highlights of the E46
IHKA syste . Features of the IHKA syste include:
• Control Panel/Module
• Single heater core for te perature regulation
• M-Bus Control of all stepper otors
• Fresh air icro filter
• Regulated A/C co pressor
• Regulated auxiliary fan operation
• Heater Control Personalization
CONTROL PANEL
All heating and air conditioning functions are carried out at the control panel. The panel is
constructed as follows:
• The three anual air distribution buttons are located on the left side of the panel for
upface vent and footwell distribution.
• The auto atic air distribution button is located on the botto of the panel along with
the te perature control - blower speed control and recirculation control buttons.
• The defrost, air conditions request and rear window defogger buttons are located on
the right side of the panel.
• The LCD atrix displays the requested te perature setting and blower speeds as on
the previous syste . There is now only one setting for te perature control.
• The interior te perature sensor and blower fan are located on the left side of the LCD
atrix.
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E46 Cli ate Control
A

FRESH AIR MICRO FILTER
The fresh air icro filter is installed in the fresh air inlet of the engine co part ent. The fil-
ter can be serviced quickly by re oving the plastic cover and re oving the filter.
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E46 Cli ate Control

TEMPERATURE REGULATION-HEATING
The E46 uses one water valve/heater core as part of interior te perature regulation. The
water valve is pulsed to control the flow of coolant through the heater core as on other sys-
te s.
Te perature regulation is based on the inputs fro :
• Te perature control switch
• Interior te perature sensor
• A bient te perature signal
• Heater core sensor
• Evaporator te perature signal
• "Y" factor
The rocker switch is used to select the desired cabin te perature which is displayed in the
atrix of the control panel. The range for te perature display is fro 60 to 90 ° F.
SERVICE STATION FEATURE - The "Service Station" feature introduced with the E38 IHKA
is integrated into the E46 IHKA. This prevents the heater core fro being flooded with hot
coolant when refueling the vehicle.
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E46 Cli ate Control

TEMPERATURE REGULATION - COOLING
Air conditioning control on the E46 is si ilar to the E39 IHKA syste . The syste uses the
variable displace ent co pressor. The swash plate of the co pressor is hinged so that is
can vary the piston travel based on the output require ents of the syste .
A
MS42.0
MS42.0
AUX. FANAUX. FAN
COMPRESSOR
PRESSURE
SENSOR
EVAPORATOR
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E46 Cli ate Control

COMPRESSOR CONTROL
Control of the A/C co pressor is a function of the Engine Control Module as in the E36.
However, the control has changed to include the regulated auxiliary fan operation.
Pressing the snowflake button is a request for A/C activation. As long as the evaporator
te perature is Above 36° F, the IHKA will signal the DME control odule to activate the
co pressor.
The IHKA control odule sends the following signals to the DME over the K-Bus and CAN
Bus via the instru ent cluster:
• Request for A/C activation (signal KO)
• Load torque for switching the co pressor on
• Requested auxiliary fan speed
The IHKA deter ines the load torque for co pressor activation and required auxiliary fan
speed fro the pressure sensor ounted on the receiver/dryer.
The pressure sensor provides a linear voltage input signal (0 - 5 volts) to the IHKA control
odule. The IHKA processes this signal and deter ines the load torque of the syste (0
to 30 N with a variable displace ent co pressor). The higher the pressure in the syste ,
the higher the voltage input signal to the IHKA.
The output signal to the DME will enable the engine control odule to odify the idle
speed, ti ing and fuel injection a ount based on the load that will be i posed when the
co pressor is activated.
The auxiliary fan is now a variable speed fan (15 stages) based on the syste load. The
DME will activate the fan through a pulse odulated final stage control.
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E46 Cli ate Control

STEPPER MOTOR M-BUS CONTROL
The E46 uses the M-Bus for stepper otor control. All five stepper otors of the IHKA
are bus controlled including:
• Two fresh air/recirc-air flap otors
• Face vent flap otor
• Footwell flap otor
• Defrost flap otor
Due to the require ent for a fast acting otor for the fresh/recirc flaps, two different step-
per otors (slow/fast) are used in the syste .
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E46 Cli ate Control

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E46 Cli ate Control
CONVERTIBLE REAR WINDOW DEFROSTER
Purpose of the System:
A two relay syste was designed for the E46iC that supplies power to either rear window
defogger grid. The two relay syste will also co unicates with the audio syste a plifi-
er to change the dyna ics of the sound for either top up/hard top installed or top down
driving
Components of the System:
Two relays, located on the right side rear quarter panel behind the interior tri cover, are
used for rear defroster operation.
• Relay K-13 receives KL 30 and the activa
tion signal fro the IHKA control odule.
The output fro the relay will switch the
rear defroster ON if the hard top is installed.
• Relay K-99 receives KL 30 fro relay K-13
and it supplies the rear defogger grid in the
soft top glass window when the top is
raised.