Originally Posted by Gijs Spruyt

Have had exactly the same issue! The system is not able to finish its calibrationrun because one of the servomotors is blocked somehow.
in my case it was the servo beneath the radio, in front, itself but it's also possible that something is blocking the connected valves and the servomotor cannot complete it's movement.

It deffinately is not the solarsensor. They never break.

Took me some time to locate the cause but the fix was easy!

Originally Posted by Rayanmx

Somebody posted the PDF Service Manuals, not sure if they're Bentley's or TIS.

But here's the information to enter diagnostic mode on the A/C

MODS: Not sure if it's ok to post this information, so feel free to edit the information if needed!

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Fig. 35: IHKA Compressor Control Communication Diagram
Courtesy of BMW OF NORTH AMERICA, INC.

Compressor Cut-out Criteria
For both versions of air conditioning the following conditions will suspend the operation of the compressor:

• Full-load acceleration
• Engine coolant temperature > 118°C (244°F)
• Engine speed > 6016 rpm
• Engine speed < 500 rpm
• Evaporator temperature < 2°C (36°F)
• Refrigerant pressure < 1.6 bar / > 30 bar (23 - 435 psi)

IHKA On Board Diagnosis


The on board diagnostics function is a special feature of the IHKA that provides three test modes:

• Mode 1 - Read fault memory
• Mode 2 - Calibration run
• Mode 3 - Manual check of functions

To access the on board diagnosis function the OFF button and the blower PLUS switch must be pressed simultaneously for approximately two seconds with the ignition in position 2. The central display panel will show a single "streamer bar" to represent mode 1 - Read fault memory. To access mode 1 the AUTO button must be pressed.

To select mode 2 or 3 it is necessary to press the OFF button, the second or third streamer bar illuminating will indicate the relevant mode to the Technician depending on how many times the OFF button is pressed. To access the mode the AUTO button must be pressed.


To exit the on board diagnosis mode the ignition must be switched to the off position.

Mode 1: Read Fault Memory
The IHKA fault memory is read and displayed in the central display panel. If no faults are present 00 is displayed and if a fault is stored FF followed by a code number is displayed. This display flashes at 0.5 Hz.

Mode 2: Calibration Run
The objective of the calibration procedure is to correct the position drift of the servomotors for temperature and air distribution control. During a calibration run:

• Both servomotors are driven to their two end positions and the new values stored in the IHKA EEPROM.
• All LED's activated simultaneously.
• Blower streamer bars individually illuminated.
• CA flashes in the central display panel at 0.5 Hz.

IHKA FAULT CODES
There are three possible operating statuses shown in the central display:

• CA = Calibration Active
• CC = Calibration Complete
• FF = Fault

Code Description


01 Solar sensor fault
02 Interior temperature sensor fault
03 Heater core temperature sensor fault
04 Air distribution servomotor feedback fault
05 Blend flap servomotor feedback fault
06 Blower switch minus fault
07 Blower switch plus fault
08 Interior sensor fan fault
09 Air distribution servomotor fault
10 Blend flap servomotor fault

Mode 3: Manual Mode

In this mode blower, air distribution, recirculation, heated screens, air conditioning ON/OFF and temperature
are manually controlled.
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Regards,
RayanMX

Originally Posted by ptkacik

According to the BMW description, Temperature is controlled by the Blend flap.

I suspect I need a blend flap acruator or a temperature control actuator (same thing).

Peter