Page 17 of 22

17
2001 model year changes
IHKA IV
The IHKA system is standard equipment on 530i, 540i/it and M5 models. It is available as
an option for the 525i/it. IHKA has been redesigned for the 2001 E39, it is identified as
IHKA IV. The carry over features from the previous version are:
Integrated control panel/module.
Separate temperature control for driver and passenger.
Air distribution control through the use of 5 “smart” stepper motors and one fast acting
hard wired stepper motor.
Automatic recirculation control (AUC).
Recirculation control via MFL.
“Rest” function for residual heat when engine is not running.
Service station feature that closes the water valves when stopped to prevent hot coolant
flooding the heater core.
A/C compressor clutch activation via a final stage control.
Stratification flap control via a bowden cable.
Please refer to the Climate Control course material ST 054 for a complete functional description of
E39 IHKA
70 0 F 640 F
-+AUTO
A
AUTO
MAX
Page 18 of 22

18
2001 model year changes
E39 IHKA IV I.P.O.
E39 IHKA IV
CONTROL
PANEL/
MODULE
MAX DEFROST
DEFROST VENT A/C COMPRESSOR
FACE VENT RECIRCULATION - AUC
FOOTWELL VENT REAR DEFROST
AUTOMATIC PROGRAM
MAX COOLING/
REST HEATING
FAN SPEED
REQUEST
INDEPENDENT DRIVER
& PASSENGER SIDE
TEMPERATURE CONTROL
HEATER CORE TEMPERATURE SENSORSEVAPORATOR
TEMPERATURE
COMPRESSOR
SHUT OFF/ON
SIGNAL (KO REL)
+ +REAR
WINDOW
DE-FOGGER
RELAY
AUTO
MAX
70 F 76 F
INTERIORAIR
BLOWER
RELAYBLOWER
RELAY
KL31KL 31KL30KL 30
KL15KL 15
M-BUSM-BUS
-FA C EVENTFLAP
-DEFROST
-FOOTWELL
-FRESHAIR/RECIRCULATION
-RAMAIRFLAP
- FACE VENT FLAP
- DEFROST
- FOOTWELL
- FRESH AIR/RECIRCULATION
- RAM AIR FLAP
FIVESTEPPER
MOTORSFIVE STEPPER
MOTORS
FRESHAIRFLAP
STEPPERMOTORFRESH AIR FLAP
STEPPER MOTOR
INTERIOR AIR TEMP
PHOTO TRANSISTOR
DIAGNOSIS AND CODING
6411839142064 118391420
6411839142064 118391420
COMPRESSOR
CONTROLCOMPRESSOR
CONTROL
AUXILIARYWATERPUMPAUXILIARY WATER PUMP
AUCGAS
SENSOR
HEATERAUC GAS
SENSOR
HEATER
K-BUSK-BUS
-Coolanttemp
-
OutsideAirTemp
-
Vehiclespeed
- Coolant temp
- Outside Air Temp
- Vehicle speed-KLR
-
RecircfromMFL
-
Diagnosis
-KLR
- Recirc from MFL
- Diagnosis
LEFT
WATER
VA LV ELEFT
WATER
VA LV ERIGHT
WATER
VA LV ERIGHT
WATER
VA LV E
-+
A
M
WASHER JET HEATING
2-8VOLT
SIGNAL2-8 VOLT
SIGNAL
MM
BLOWERMOTOR
OUTPUTSTAGEBLOWER MOTOR
OUTPUT STAGE
+
BLOWER
BMWDISB
M
WD
I
SBMWDISBMWDIS
DSC III
kjhsdfkhsdflkhsdlkfjhlkjghkg
lkdkfljdflkjdsfljdslfjldskjflkjdflk
ldsflsdfklhdsfhsdfhsdkhfkhsdf
kldjfkljdfkjdskfkjdskfjkljdfkldsfk
kjsdfkljsdfkdsfkjdsfkljsdfkjds
ldjsfklkjsdfkldsjfkdsjfkdsfkdfklk
K-BUS
DME
SOLAR SENSORSAUC OXIDIZABLE
GAS SENSOR
Page 19 of 22

19
2001 model year changes
Changes made to the E39 IHKA
New Control Unit (since 9/00).
Addition of solar sensor (since 9/00).
New IHKA integrated heater and air conditioning case (since 3/00).
IHKA IV Control Unit
The “REST” button on the control unit has been
replaced with a “MAX” button. Two different functions
are carried out by pushing the MAX button:
Maximum cooling function
Residual heat function
Determination of which function will be enabled is
based on switching criteria.
A/C MAX function
(This feature was introduced in the E38 since 9/99)
Maximum cooling performance is automatically activated by pressing the MAX button. An
LED on the button illuminates to indicate that the function is active.
Criteria for operation:
Terminal 15 “on” , MAX button pressed and outside temperature above 60
oF.
The following settings are adjusted or activated:
Temperature control is canceled and the temperature display indicates 60
o F.
Both water valves are closed.
The left and right Y-factors are set to -27.5%.
The compressor is switched on (LED turns on in the A/C switch).
The blower setting is set to maximum.
Recirculation is activated (LED turns on in the re-circ switch).
Air distribution is set to center vents only.
Operation of the max defrost is overridden by selecting MAX. The operation of the rear win-
dow defogger is not affected.
Page 20 of 22

20
2001 model year changes
REST Function
The REST function continues to operate as usual except that the MAX button has taken the
place of the REST button. Activation criteria continues to be:
Ignition “OFF” or in KL R.
“MAX” button pressed.
Outside temperature below 60
o F.
Coolant temperature above 80o C.
Battery voltage above 11.4V.
The REST feature operates as previously.
Diagnostics
The IHKA IV diagnosis has been upgraded to the E46 style diagnostic program.
Solar Sensor
The IHKA IV integrates the solar sensor into the
calculation used to automatically regulate the
interior vehicle temperature. The sensor is
located in the right side defrost outlet.
In the case of a very sunny day, the interior
warms faster than the control unit can compen-
sate for. Similar is true if the weather suddenly
becomes overcast.
The input of the solar sensor in the E39 can
affect the operation of:
Blower setting
Air distribution to center vent
Because the E39 IHKA IV is a dual zone system. the solar sensor housing contains two
photo-resistors that measure solar radiation on the left and right halves of the interior.
(Please refer to the Solar Sensor module in the 2000
Systems Diagnosis training course ST 039 for a com-
plete description of the solar sensor operation and
diagnosis)
Solar Sensor
Two photo-resistors
inside of housing
Page 21 of 22

21
2001 model year changes
IHKA integrated heater and air conditioning case
The E39 IHKA case has been redesigned since 3/00. The E39 and E53 both share the
same case design.
The difference from the previous case is that a single flap (left and right), controls both the
fresh air and recirculation inlets. Ram air is controlled by a separate flap. What makes it
possible to use a single flap for fresh air/re-circ is the semi-circular door; as one inlet is cov-
ered another is opened.
Please refer to the Climate Control course material ST 054 for a complete functional description of
ram air pressure compensation.
1. Stepper motor for footwell
2. Stepper motor for rear compartment, stratification
3. Fresh air/recirculation flap
4. Output stage for blower motor
5. Stepper motor for ram air flap
6. Ram air flap
Stepper motors for the fresh air/recirculation,
defrost and ventilation flaps are located on the
left side of the housing
3
6
4
2
15
Right Side of IHKA IV Case
Ram air and fresh air/re-circ flaps as seen from the engine side of the bulkhead
Page 22 of 22
22
2001 model year changes
E39 Rear Head Protection System (HPS)
For 2001, rear head protection airbags (HPS)
will be available for sedans ordered with rear
side airbags.
The airbags are a cushion (not an ITS) that is
deployed from the C-pillar. The HPS will n no
ot
t
be
de-activated along with the side airbags from
the factory since there is no danger to small
children sitting out of position.
A vehicle with rear HPS can be identified by
observing “HPS” embossed in the C-pillar
cover.
Rear airbags with HPS will be standard equipment on the 2001 E39 M5.
Review Questions
1. What addition was made to the 16 pin OBD connector that made diagnosis possible
with the DIS/MoDiC?
2. Describe the procedure to reset the Service Interval Indicator from the instrument
cluster.
3. How does the E39 IHKR system maintain the desired cabin temperature?
4. Was the “REST” feature deleted from the IHKA IV system?
5. What was the addition made to the rear airbag system of the 2001 E39?
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