Diagnostic Functions

Diagnostic functions

General
The climate control module (CCM) has a built-in diagnostic system which continuously monitors internal functions and input and output signals.

Diagnostic trouble codes (DTCs)
Diagnostic trouble codes (DTCs) are stored in the control module if the climate control module (CCM) detects a fault. Every diagnostic trouble code (DTC) has a counter which records the number of cycles which have been "fault-free" since the diagnostic trouble code (DTC) was stored. A fault which is detected in each operating cycle is defined as permanent. A fault which is detected in one or more operating cycles (although not the present one) is defined as intermittent.
An operating cycle is the period from when the ignition was switched on, remained on for at least 10 seconds and was finally switched off for at least 10 seconds.

Reading and erasing diagnostic trouble codes (DTCs)
Stored diagnostic trouble codes (DTCs) can be read off and erased using this function.

Reading off input and output signals
Using this function, the status or value of parameters can be read off. The presentation of the status or value can be obtained graphically or digitally.
For further information about the different parameters, see Description of parameters Description Of Parameters.

Reading off extended fault-tracing information
This function can be used to read parameters, status identifiers and counters stored at the same time as a diagnostic trouble code (DTC). These are called frozen values.
For further information, see Frozen values climate control module, description Frozen Values Climate Control Module, Description.

Description of programmable parameters, customer adaptation
Certain parameters for the climate control module (CCM) can be read off and programmed using this function. The purpose of this programming is to:
- read the programmed parameters before replacing the control module. This is so the same parameters can be entered into the new control module
- to adapt the function of the control module for the equipment levels of the car (passenger compartment ventilation filter, parking heater)
- to adapt the function of the control module to the requirements of the driver.

Passenger compartment ventilation filter compensation, status
Indicates the status for the activation of passenger compartment ventilation filter compensation.
OFF = Compensation not active
ON = Compensation active (preset)

Blower fan run-on, status
Provides the status for activation of the blower fan run-on. The run-on dries the evaporator and prevents bad odors which may otherwise result from residual moisture in the system.
OFF = Run-on inactive
ON = Run-on active (preset)

Blower fan speed, value
Allows the speed to be modified for the blower fan when the climate control system is in AUTO mode. Modifying the parameters means that the climate control system either blows more or less air than the preprogrammed value, to correspond to the request of the driver.
Gives the voltage value for adaptation of the blower fan speed.
-1.0 - +1.0 V (0 V preset)

Setting for air distribution for the floor / defroster residual heat, value
Indicates the setting of the air distribution between the floor and defroster.
10/90 - 90/10% (70/30% preset)

Setting for air distribution for the floor / defroster parking heater, value
Indicates the setting of the air distribution between the floor and defroster.
10/90 - 90/10% (70/30% preset)

Passenger compartment temperature, value
The passenger compartment temperature in relation to the passenger compartment temperature switch position can be adjusted by programming a compensation value.
The passenger compartment temperature can be raised or lowered by a maximum of ±2 °C (±4 °F) from the normal value. This allows the temperature to be adjusted in accordance with the driver's wishes.
0 = -1.0 °C/-2.0 °F
1 = -0.5 °C/-1.0 °F
2 = 0.0 °C / 0.0 °F (default value)
3 = +0.5 °C/+1.0 °F
4 = +1.0 °C/+2.0 °F

Description of components/functions activation

Self-adjustment of damper motors
This function can be used to carry out self adjustment of the limit positions for all the damper motors. Self adjustment must be carried out if, after checks, one or more of the damper motors do not reach their limit positions or the climate control module (CCM) is replaced. There are a number of possible reasons for a damper motor not reaching its end position. For example, the motor or the damper has been turned manually, the voltage supply may have been cut, or a component has been replaced.