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Home >> Mercedes Benz >> 2019 >> C300 4Matic, 2D Convertible >> Repair and Diagnosis >> External Pages >> Different car >> Section 327 (Climate Control - 253 Chassis 1 Of 3) >> Basic Knowledge >> Pre-Entry Climate Control, Function - GF83.40-P-2014RF

Pre-Entry Climate Control, Function - GF83.40-P-2014RF

WARNING: This page is about a different car, the 2023 Mercedes-Benz GLC300, 2022 Mercedes-Benz GLC300, 2021 Mercedes-Benz GLC300, 2020 Mercedes-Benz GLC350e, and 2020 Mercedes-Benz GLC300. However, it is still accessible from the selected car via links, so may be relevant.

Model 205 (except 205.012/013/047/053/054/147/212/213/247/253) with code 577 (Remote activation of heating and ventilation systems) 

Model 205.012/013/047/053/054/147/212/213/247/253, 253.311/354/911/953/954/99 

G14188744Courtesy of MERCEDES-BENZ USA

Function requirements, general 

The electronic ignition lock control unit sends the status of terminal 15 via interior CAN to the A/C control unit.

Pre-entry climate control in general 

The vehicle interior of the parked vehicle can be preheated or pre-cooled as needed before starting to drive and the air quality improved (with code P21 (Air quality package)).

The pre-entry climate control can be switched on as follows:

On model 205.013/047/053/054/147/213/247/253, model 253.311/354/911/953/954/99, the pre-entry climate control can be operated using, for example a smartphone, tablet or PC with a browser. The current operating condition of the pre-entry climate control is shown there.

For this purpose, the climate control control unit continuously transmits information on the operating status of the auxiliary climate control via the interior CAN, electronic ignition lock control unit and diagnostics

CAN to:

The information stored there can be retrieved using the smart phone, tablet or PC, for example. The information is provided by request only. The telematics services communication module (with code B57 (Communication module battery level)) transmits data using the communication module/stationary heater antenna splitter (with code B24 (Remote control for auxiliary heating)) and the communication module/stationary heater antenna. The HERMES control unit (model 205.013/047/053/054/147/213/247/253, model 253.311/354/911/953/954/99 with code 360 (HERMES UMTS)) transmits data using the emergency call system antenna. On model 205.047 and with code 348 (Emergency call/assist system), the emergency call system control unit sends the data via the telephone antenna splitter, the left telephone antenna and the right telephone antenna. In the event of poor reception or a failure of the telephone antenna splitter, the left telephone antenna or the right telephone antenna, the emergency call system control unit automatically uses the emergency call system antenna to send and receive the mobile phone signals.

The auxiliary climate control comprises the following functions:

Auxiliary climate control via remote activation (model 205 with code 577 (Remote activation of heating and ventilation systems)) 

The pre-entry climate control can be requested via the separate pre-entry climate control button on the transmitter key.

Vehicles except code 889 (KEYLESS-GO) and except code 893 (KEYLESS-Start):

When the pre-entry climate control button is pressed, the transmitter key sends the access authorization code and the request to start the pre-entry climate control via the rear window antenna and the FM 1, AM, CL and KEYLESS-GO antenna amplifier to the electronic ignition lock control unit. If the access authorization code is valid, the electronic ignition lock control unit sends the request for starting the pre-entry climate control to the A/C control unit via interior CAN. The A/C control unit then starts the pre-entry climate control.

If cooling is required, the following functions are started:

The climate control control unit sends the request to switch on the blower motor over the climate control LIN 2 to the blower regulator, which actuates the blower motor directly.

The climate control control unit sends the request to switch on the seat ventilation via interior CAN to the rear SAM control unit.

IMPORTANT The seat ventilation remains switched on even after starting the vehicle.

If cooling mode was activated, ventilation takes place for a maximum of 120 min. The cooling mode is terminated after this time has lapsed or when circuit 15 is switched on or when the vehicle is started.

Vehicles with code 889 (KEYLESS-GO) or code 893 (KEYLESS-Start): When the pre-entry climate control button is pressed, the transmitter key sends the access authorization code and the request to start the pre-entry climate control via the rear window antenna and the FM 1, AM, CL and KEYLESS-GO antenna amplifier to the KEYLESS-GO control unit. The KEYLESS-GO control unit sends this radio signal to the electronic ignition lock control unit via interior CAN. If the access authorization code is valid, the electronic ignition lock control unit sends the request for starting the pre-entry climate control to the A/C control unit via interior CAN. The A/C control unit then starts the pre-entry climate control.

To operate the pre-entry climate control, the A/C control unit assesses the outside temperature:

The outside temperature sensor measures the outside temperature. The front SAM control unit reads in the signal of the outside temperature sensor directly, calculates the outside temperature and transmits it to the A/C control unit over the interior CAN. The climate control control unit then evaluates the outside temperature. The heating functions are activated at outside temperatures below 20°C.

The ventilation functions are activated at outside temperatures above 20°C.

If heating is required, the following functions are started:

The climate control control unit sends the request to switch on the seat heater via interior CAN to the rear SAM control unit.

IMPORTANT The seat heating remains switched on even after starting the vehicle.

IMPORTANT The steering wheel heater also remains switched on after starting the vehicle.

The A/C control unit sends the request to switch on the rear window heater via interior CAN to the rear SAM control unit.

The A/C control unit sends the request to switch on the mirror heater via interior CAN to the left front door control unit and to the right front door control unit.

IMPORTANT The mirror heater also remains switched on after starting the vehicle.

If heating mode was activated, heating takes place for a maximum of 10 min. The heating mode is terminated after this time has lapsed or when circuit 15 is switched on or when the vehicle is started. The pre-entry climate control can be activated two times if the onboard electrical system is sufficiently stable.

Additional function requirements for pre-entry climate control by unlocking vehicle (model 205.012/013/047/053/054/147/212/213/247/253, model 253.311/354/911/953/954/99) 

The head unit sends the status of the pre-entry climate control over the user interface CAN, electronic ignition lock control unit and the interior CAN to the climate control control unit.

Pre-entry climate control by unlocking vehicle (model 205.012/013/047/053/054/147/212/213/247/253, model 253.311/354/911/953/954/99) 

The objective of pre-entry climate control by unlocking (using transmitter key or KEYLESS-GO (with code 889 (KEYLESS-GO))) the central locking system is to briefly preheat or preventilate the area of the driver's side (model 205.012/212) and/or the area of the driver's side or vehicle interior (model 205.013/047/053/054/147/213/247/253, model 253.311/354/911/953/954/99) when entering the vehicle and to precool the air from the air vents.

The electronic ignition lock control unit sends the status of the central locking over the interior CAN to the climate-control control unit. The climate control control unit checks the pre-configuration and then starts the pre-entry climate control.

To operate the pre-entry climate control, the climate control control unit assesses the following information:

The interior temperature is recorded by the interior temperature sensor with integrated fan in the overhead control panel control unit. The overhead control panel control unit transmits information about the interior temperature to the climate control control unit via the interior CAN. The fan sucks in the air for temperature measurement from the vehicle interior.

Model 205.012/212:

If the vehicle interior temperature is at least 4°C above the set specified temperature, the vehicle is cooled. If the vehicle interior temperature is at least 4°C below the set specified temperature, the vehicle is heated. If the lowest possible specified temperature is set on the climate control operating unit, the vehicle is always cooled. If the highest possible specified temperature is set on the climate control operating unit, the vehicle is always heated.

If cooling is required, the following functions are started:

The climate control control unit actuates the electric A/C compressor over the climate control LIN 2 and sends the request to switch on the blower motor over the climate control LIN 2 to the blower regulator, which then directly actuates the blower motor.

IMPORTANT The seat ventilation remains switched on even after starting the vehicle.

If cooling mode has been activated, cooling takes place for a maximum of 120 s (model 205.012/212) or 300 s (model 205.013/047/053/054/147/213/247/253, model 253.311/354/911/953/954/99). Cooling mode is ended after this time has expired, when the vehicle is started or when the pre-entry climate control button is pressed (model 205.013/047/053/054/147/213/247/253, model 253.311/354/911/953/954/99).

If heating is required, the following functions are started:

The climate control control unit actuates the high voltage PTC heater over the climate control LIN 2. The high voltage PTC heater heats up the coolant. The coolant temperature in the high voltage PTC heater is recorded by the temperature sensor for the high voltage PTC heater. The coolant temperature is sent by the high voltage PTC heater over the climate control LIN 2 to the climate control control unit. If the coolant has reached a temperature of 35°C, the climate control control unit directly actuates the heating circuit circulation pump and sends a request to the high-voltage PTC heater via climate control LIN 2 to switch on the high-voltage PTC heater switchover valve. The high-voltage PTC heater actuates the high-voltage PTC heater switchover valve directly. The high-voltage PTC heater switchover valve regulates the flow of coolant (small or large coolant circuit).

The climate control control unit actuates the electric A/C compressor over the climate control LIN 2 and sends the request to switch on the blower motor over the climate control LIN 2 to the blower regulator, which then directly actuates the blower motor. The electric refrigerant compressor is activated to dry the air flowing out and thus prevent fogging of windows.

Model 205.013/047/053/054/147/213/247/253, model 253.311/354/911/953/954/99:

If the interior temperature is above the selected specified temperature, the vehicle is cooled. If the interior temperature is below the selected specified temperature, the vehicle is heated.

The climate control control unit sends the request to switch on the seat heater via interior CAN to the rear SAM control unit.

IMPORTANT The seat heating remains switched on even after starting the vehicle.

IMPORTANT The steering wheel heater also remains switched on after starting the vehicle.

The A/C control unit sends the request to switch on the rear window heater via interior CAN to the rear SAM control unit.

The A/C control unit sends the request to switch on the mirror heater via interior CAN to the left front door control unit and to the right front door control unit.

IMPORTANT The mirror heater also remains switched on after starting the vehicle.

If heating mode has been activated, heating takes place for a maximum of 120 s (model 205.012/212) or 300 s (model 205.013/047/053/054/147/213/247/253, model 253.311/354/911/953/954/99). Heating mode is ended after this time has expired, when the vehicle is started or when the pre-entry climate control button is pressed (model 205.013/047/053/054/147/213/247/253, model 253.311/354/911/953/954/99).

If the on-board electrical system is sufficiently stable, the pre-entry climate control can be activated once (model 205.012/212) or twice (model 205.013/047/053/054/147/213/247/253, model 253.311/354/911/953/954/99).

Additional function requirement for pre-entry climate control at departure time (model 205.013/047/053/054/147/213/247/253, model 253.311/354/911/953/954/99) 

The head unit sends the "setting request" for pre-entry climate control over the user interface CAN, electronic ignition lock control unit and the interior CAN to the climate control control unit.

The telematics services communication module (with code B57 (Communication module battery level)) receives data regarding web-based activation of pre-entry climate control at departure time via the communication module/stationary heater antenna and the communication module/stationary heater antenna splitter (with code B24 (Remote control for auxiliary heating)). The HERMES control unit (model 205.013/047/053/054/147/213/247/253, model 253.311/354/911/953/954/99 with code 360 (HERMES UMTS)) receives data via the emergency call system antenna. On model 205.047 and with code 348 (Emergency call/assist system), the emergency call system control unit sends the data for web-based activation of the pre-entry climate control at departure time via the left telephone antenna, the right telephone antenna and the telephone antenna splitter. In the event of poor reception or a failure of the telephone antenna splitter, the left telephone antenna or the right telephone antenna, the emergency call system control unit automatically uses the emergency call system antenna to send and receive the mobile phone signals. The telematics services communication module (with code B57 (Communication module battery level)), the HERMES control unit (model 205.013/047/053/054/147/213/247/253, model 253.311/354/911/953/954/99 with code 360 (HERMES UMTS)) or the emergency call system control unit (model 205.047 and with code 348 (Emergency call/assistance system)) transmits the received requests to the climate control control unit via the diagnostic CAN, electronic ignition lock control unit and interior CAN.

Pre-entry climate control at departure time (model 205.013/047/053/054/147/213/247/253, model 253.311/354/911/953/954/99) 

The objective of the pre-entry climate control at departure time is to pre-heat or pre-cool the vehicle interior prior to departure.

Set a departure time:

The departure time can be set, selected and activated via the menu structure in the instrument cluster or web-based via a browser, e.g. using a smartphone, a tablet or a PC. Up to three departure times can be configured.

The outside temperature sensor measures the outside temperature. The front SAM control unit reads in the signal of the outside temperature sensor directly, calculates the outside temperature and transmits it to the A/C control unit over the interior CAN.

The sun sensor integrated in the rain/light sensor with additional functions records the angle of incidence and the intensity of the solar radiation. The signals of the rain/light sensor with additional functions are read in by the front SAM control unit via the rain/light sensor LIN. The front SAM control unit sends the signals over the interior CAN to the A/C control unit. For example, in the event of one-sided solar radiation, an appropriate temperature difference is set between the left and the right specified control temperatures.

If the interior temperature is above the selected specified temperature, the vehicle is cooled. If the interior temperature is below the selected specified temperature, the vehicle is heated.

If cooling is required, the following functions are started:

The climate control control unit actuates the electric A/C compressor over the climate control LIN 2 and sends the request to switch on the blower motor over the climate control LIN 2 to the blower regulator, which then directly actuates the blower motor.

IMPORTANT The seat ventilation remains switched on even after starting the vehicle.

If heating is required, the following functions are started:

The climate control control unit actuates the electric A/C compressor over the climate control LIN 2 and sends the request to switch on the blower motor over the climate control LIN 2 to the blower regulator, which then directly actuates the blower motor. The refrigerant compressor is activated in order to ensure that the air flowing out is dried, thus preventing fogging of the windows. The climate control control unit actuates the high voltage PTC heater over the climate control LIN 2. The high voltage PTC heater heats up the coolant. The coolant temperature in the high voltage PTC heater is recorded by the temperature sensor for the high voltage PTC heater. The coolant temperature is sent by the high voltage PTC heater over the climate control LIN 2 to the climate control control unit. If the coolant has reached a temperature of 35°C, the climate control control unit directly actuates the heating

The instrument cluster transmits the activated departure time via the user interface CAN, electronic ignition lock control unit and interior CAN to the climate control control unit. The climate control control unit calculates the required starting time for the pre-entry climate control and sends this via the interior CAN, electronic ignition lock control unit, and chassis FlexRay to the powertrain control unit. When the starting time is reached, the powertrain control unit sends the request for pre-entry climate control via chassis FlexRay, electronic ignition lock control unit and interior CAN to the climate control control unit.

The telematics services communication module (with code B57 (Communication module battery level)), the HERMES control unit (model 205.013/047/053/054/147/213/247/253, model 253.311/354/911/953/954/99 with code 360 (HERMES UMTS)) or the emergency call system control unit (model 205.047 and with code 348 (Emergency call/assistance system)) transmits the received requests to the powertrain control unit via the diagnostic CAN, electronic ignition lock control unit and suspension FlexRay. The powertrain control unit then sends the activated departure time via chassis FlexRay, electronic ignition lock control unit and user interface CAN to the instrument cluster, which stores this. The climate control control unit calculates the required starting time for the pre-entry climate control and sends this via the interior CAN, electronic ignition lock control unit, and chassis FlexRay to the powertrain control unit. When the starting time is reached, the powertrain control unit sends the request for pre-entry climate control via chassis FlexRay, electronic ignition lock control unit and interior CAN to the climate control control unit.

When the departure time is activated, the LED in the pre-entry climate control button lights up yellow. The request to switch on the LED is transmitted by the powertrain control unit via chassis FlexRay, electronic ignition lock control unit, interior CAN, climate control control unit and the climate control LIN to the climate control operating unit. The climate control operating unit actuates the LED in the pre-entry climate control button directly.

To operate the pre-entry climate control at the departure time, the climate control control unit assesses the following information:

The interior temperature is recorded by the interior temperature sensor with integrated fan in the overhead control panel control unit. The overhead control panel control unit transmits information about the interior temperature to the climate control control unit via the interior CAN. The fan sucks in the air for temperature measurement from the vehicle interior.

The climate control control unit sends the request to switch on the seat heater via interior CAN to the rear SAM control unit.

IMPORTANT The seat heating remains switched on even after starting the vehicle.

IMPORTANT The steering wheel heater also remains switched on after starting the vehicle.

The A/C control unit sends the request to switch on the rear window heater via interior CAN to the rear SAM control unit.

The A/C control unit sends the request to switch on the mirror heater via interior CAN to the left front door control unit and to the right front door control unit.

IMPORTANT The mirror heater also remains switched on after starting the vehicle.

IMPORTANT The steering wheel heater and the mirror heater are actuated for max. 8 min and the seat heater and the rear window heater for max. 13 min before the departure time is reached.

The vehicle interior is cooled or heated until the desired temperature in relation to the set departure time has been reached. The vehicle interior then continues to be air-conditioned and the temperature is maintained. For this purpose, pre-entry climate control is activated max. 55 min. If the departure is delayed, the vehicle interior is air-conditioned for an additional 5 min.

If the vehicle is connected to a power supply, the charging of the high-voltage battery to the specified minimum charge level has priority. The pre-entry climate control at the departure time is only activated following this.

If the vehicle is not connected to a power supply and the high-voltage battery is not completely charged, the operating time of the pre-entry climate control may be shortened.

Even if the vehicle is connected to power supply equipment and the high-voltage battery was completely charged, the high-voltage battery can discharge during pre-entry climate control. Auxiliary climate control is ended when the vehicle is started, when the auxiliary climate control button is pressed or if 5 min have passed since the selected departure time expired.

Pre-entry climate control using pre-entry climate control button (model 205.013/047/053/054/147/213/247/253, model 253.311/354/911/953/954/99) 

The outside temperature sensor measures the outside

The pre-entry climate control can also be switched on after the desired interior temperature has already been reached. This allows the vehicle interior to be further air-conditioned and the interior temperature to be maintained at a constant level (e.g. also during an interruption in travel) for up to 50 min.

The auxiliary climate control is switched on and off by pressing the auxiliary climate control button in the air conditioning control panel. The climate control operating unit sends the status of the pre-entry climate control button via the climate control LIN to the climate control control unit.

Using the indicator lamps in the pre-entry climate control button, the current operating condition of the pre-entry climate control is shown:

To operate the auxiliary climate control by pressing the auxiliary climate control button, the climate control control unit assesses the following information:

The interior temperature is recorded by the interior temperature sensor with integrated fan in the overhead control panel control unit. The overhead control panel control unit transmits information about the interior temperature to the climate control control unit via the interior CAN. The fan sucks in the air for temperature measurement from the vehicle interior.

CAN.

The sun sensor integrated in the rain/light sensor with additional functions records the angle of incidence and the intensity of the solar radiation. The signals of the rain/light sensor with additional functions are read in by the front SAM control unit via the rain/light sensor LIN. The front SAM control unit sends the signals over the interior CAN to the A/C control unit. For example, in the event of one-sided solar radiation, an appropriate temperature difference is set between the left and the right specified control temperatures. If cooling is required, the following functions are started:

The climate control control unit actuates the electric A/C compressor over the climate control LIN 2 and sends the request to switch on the blower motor over the climate control LIN 2 to the blower regulator, which then directly actuates the blower motor.

The climate control control unit sends the request to switch on the seat ventilation via interior CAN to the rear SAM control unit.

IMPORTANT The seat ventilation remains switched on even after starting the vehicle.

If heating is required, the following functions are started:

The climate control control unit actuates the electric A/C compressor over the climate control LIN 2 and sends the request to switch on the blower motor over the climate control LIN 2 to the blower regulator, which then directly actuates the blower motor. The refrigerant compressor is activated in order to ensure that the air flowing out is dried, thus preventing fogging of the windows. The climate control control unit actuates the high voltage PTC heater over the climate control LIN 2. The high voltage PTC heater heats up the coolant. The coolant temperature in the high voltage PTC heater is recorded by the temperature sensor for the high voltage PTC heater. The coolant temperature is sent by the high voltage PTC heater over the climate control LIN 2 to the climate control control unit. If the coolant has reached a temperature of 35°C, the climate control control unit directly actuates the heating circuit circulation pump and sends a request to the high-voltage PTC heater via climate control LIN 2 to switch on the high-voltage PTC heater switchover valve. The high-voltage PTC heater actuates the high-voltage PTC heater switchover valve directly. The high-voltage PTC heater switchover valve regulates the flow of coolant (small or large coolant circuit).

The climate control control unit sends the request to switch on the seat heater via interior CAN to the rear SAM control unit.

IMPORTANT The seat heating remains switched on even after starting the vehicle.

The A/C control unit sends the request to switch on the rear window heater via interior CAN to the rear SAM control unit.

The A/C control unit sends the request to switch on the mirror heater via interior CAN to the left front door control unit and to the right front door control unit.

IMPORTANT The mirror heater also remains switched on after starting the vehicle.

Additional function requirements for starting air quality improvement (with code P21 (Air Quality package)) 

The head unit sends the status of the ionization via user interface CAN, electronic ignition lock control unit and the interior CAN to the climate control control unit.

Both functions cannot be selected separately. Even if the vehicle is neither cooled nor ventilated based on the evaluation of the environmental data, both functions are activated at the time that is included in the function sequence for the corresponding type of activation of the pre-entry climate control and switched off after 60 s. On model 205 with code 577 (Remote activation of heating and ventilation systems), both functions are switched off after a period of

The head unit sends the status of the fragrancing via user interface CAN, electronic ignition lock control unit and the interior CAN to the climate control control unit.

Start air quality improvement (with code P21 (Air Quality package)) 

To improve the air quality in the vehicle, the following additional functions are also activated when starting the pre-entry climate control, if they were previously activated via the operation menu in the head unit:

10 min (heating) or 5 min (cooling).

IMPORTANT Ionization and fragrancing remain switched on even after starting the vehicle.

  Electrical function schematic for preconditioning system   PE83.40-P-2059-97FBA
  Overview of system components for climate control   GF83.40-P-9994RF 
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