Function
Function
General
Vehicle configuration can be read out to see the functions with which the vehicle is equipped.
The following affect the heater function:
- parking and auxiliary heater function or auxiliary heater function only (diesel engines)
- parking heater or not (gasoline engines)
- remote start
Auxiliary heater (diesel engines only)
An auxiliary heater comes as standard on diesel-engine vehicles in certain markets (cold climates). This function is used to provide extra heat to the climate control system. The auxiliary heater works the same as the parking heater, but with other start conditions. The start conditions are governed by the climate control module (CCM) (4/6).
The climate control module (CCM) requests that the heater is started.
Certain conditions must be met before the heater can start. These are:
- outside temperature below +5 °C/41 °F (the heater switches off at +8 °C/46.4 °F)
- engine speed (RPM) greater than 500 rpm
- quantity of fuel more than 7.5 liters for the engine coolant heater and 4.5 liters for the parking heater
- no diagnostic trouble code that prevents heater start is stored in the combustion preheater module (CPM)
- an airbag has not deployed.
When the heater is activated the information lamp illuminates and a message is displayed in the driver information module (DIM) (5/1).
Parking heater
The driver seats the desired departure time using one of the two timer functions in the driver information module (DIM) (5/1) display. Time is set using the left control stalk.
If the engine has not been started since the last timer start of the heater, the combustion preheater module (CPM) (4/7) will not allow another start of the heater until the engine has been started.
The central electronic module (CEM) (4/56) receives information on desired departure time from the steering wheel module (SWM) (3/130) and driver information module (DIM).
Approximately 50 minutes before the desired departure time, the central electronic module (CEM) transmits information to the combustion preheater module (CPM) about:
- outside temperature
- quantity of fuel
- the operating status of the vehicle
- a request to calculate the start time of the heater.
The combustion preheater module (CPM) calculates start time based on information from the central electronic module (CEM) and starts the heater at the calculated time point. The heater calculates when to start (15-60 minutes before the planned departure at temperatures between -30 °C/-22 °F and +15 °C/59 °F).
The heater runs max. 60 minutes at temperatures below -10 °C/14 °F.
The heater runs a minimum of 15 minutes before the desired departure time. (Temperatures between +15 °C/59 °F and +25 °C/77 °F).
When the heater is started directly using the control stalk, it runs until it is shut off or for a maximum of 60 minutes. The coolant pump and blower fan remain activated for 2 minutes after the set departure time to allow for the driver getting to the car late.
A text message is displayed in the driver information module (DIM) when the heater is activated.
Auxiliary heater and parking heater
If a diesel engine vehicle has a parking heater, the vehicle will have both the auxiliary heater and parking heater functions.
If the driver has programmed the parking heater, but arrives early, the auxiliary heater takes over when the vehicle is started. The auxiliary heater then determines whether the heater should be active if the driver has not manually deactivated the function using the control stalk of the steering wheel module (SWM) (3/130).
Remote start
With the remote start system, the parking heater in the vehicle can be started or turned off from a distance of up to 600 meters (656 yards). External influences, local conditions and densely built-up areas may limit the range. The handheld transmitter indicates whether the signal was received by the heater as well as the status of the internal batteries.