Special Functions

Control Panel/Module Test Display (12-95 to 3-97 production)




The E36 IHKA control panel/module includes additional programming that allows system diagnosis without the use of the DIS or MoDiC; sensor values and other inputs are shown on the LCD display. This function is found on systems produced from 12-95 thru 3-97.

The sensor display mode is activated by pressing the "AUTO" and rear window defroster buttons simultaneously.






Available displays are:

1. Interior temperature
2. Ambient temperature
3. Left heater core temperature
4. Right heater core temperature
5. Evaporator temperature
6. Engine speed
7. Road (vehicle) speed
8. Y-factor value
9. Fresh-air flap position (in % up to 99.5%)
10. AUC sensor voltage (if equipped)
11. Battery voltage
12. Software version.

The sensor display is switched "Off" by pressing the "AUTO" and recirculating air buttons simultaneously, or by switching the ignition "Off."






NOTE: The control panel/module LED display does not include a decimal point or percent symbol, so 99.5% is displayed as 995.

Temperatures are always shown in degrees Celsius, regardless of module coding. Blower speed cannot be adjusted during sensor display mode.

Service-Station Feature

This service station feature continues on IHKA E36. The control panel/module continues to power both coolant valves closed for about 3 minutes after the ignition is switched "Off." This feature prevents the heater cores from being flooded with hot coolant when the engine is shut off for brief periods (e.g. during refueling).

Cold Start Arrest

IHKA E36 also includes an automatically activated cold start arrest function. The control panel/ module checks for the necessary conditions at engine start-up:

- IHKA system turned "on" and
- Maximum defrosting request is not present and
- Left Y-factor is 100% (maximum heating required) and
- Left side "AUTO" mode request is present and
- Left heater core temperature is less than 68°F (20°C).

If these conditions exist, the control panel/module will:

- Open the defroster flaps and
- Close all other air distribution flaps and
- Operate the blower motor, A/C compressor; fresh air flaps, and recirc. air flaps according to control panel/module settings.

When the left heater core temperature reaches 68°F (20°C), cold start arrest ends and all IHKA system functions depend upon control panel/module settings and sensed conditions.

Calibration Run

The control panel/module initiates a "calibration run" every 20th time the ignition switch is turned to "Off." The calibration run is necessary because the stepper motors move relative to the end-of-travel position (0% or 100%).