Cooling system (B8444S only)
The engine control module (ECM) controls the variable A/C compressor. When the A/C switch on the dashboard environment panel is activated, a request is transmitted via the control area network (CAN) to the engine control module (ECM) about the activation of the compressor. The engine control module (ECM) calculates the current to open the valve to control the variable A/C compressor. If any of the following conditions are met, the valve that activates the compressor is not opened
- high engine coolant temperature (ECT)
- wide open throttle (WOT)
- the engine has just been started
- overpressure in the air conditioning (A/C) system.
When the engine is started the engine control module (ECM) activates the air conditioning compressor for a short period even if the climate control module (CCM) has not transmitted a request for this.
This is carried out for diagnosis and maintenance at all temperatures exceeding 0 °C.
Scheme 286
The evaporator temperature sensor is installed on the heater. Its role is to inform the climate control module (CCM) of the temperature of the refrigerant. The climate control module (CCM) controls the request from the evaporator temperature sensor to activate the air conditioning compressor. The evaporator temperature sensor is directly connected to the climate control module (CCM).
There are diagnostics for the evaporator temperature sensor.
Scheme 287
The air quality sensor (AQS) is available as an option for ECC. The air quality sensor (AQS) is, together with a particle filter, part of a system which has the role of ensuring that the air in the passenger compartment is free of pollutants. The role of the air quality sensor (AQS) is to transmit a signal to the climate control module (CCM) if it detects increased concentrations of pollutants in the outside air.
The air quality sensor (AQS) measures concentrations of COx and NOx.
The air quality sensor (AQS) compares the present values with previous ones and can calculate changes in pollutant concentrations.
The air quality sensor (AQS) communicates with the climate control module (CCM) via a LIN bus.
The signal from the air quality sensor (AQS) to the climate control module (CCM) has four steps, 0-3
- off = no increase or reduction in pollutant level
- signal 1 = gradual increase in pollutant level
- signal 2 = medium increase in pollutant level
- signal 3 = rapid increase in pollutant level.
The climate control module (CCM) uses the signal to control the recirculation damper motor.
There are diagnostics for the air quality sensor (AQS).
Scheme 288
The system for the seat heaters consists of three different parts
- a seat heating module (SHM) which controls the function for communicating with the climate control module (CCM)
- two heater pads
- a temperature sensor.
The seat heating module (SHM) is under the left and right-hand front seat. The heater pads are in the seat and backrest. The temperature sensor is in the seat.
The seat heating module (SHM) is directly connected to the heater pad and temperature sensor. The seat heating module (SHM) communicates with the climate control module (CCM) via a LIN bus.
There are diagnostics for the seat heating module (SHM).
Across the lower section of the dashboard environment panel there is a 12V socket and space for a maximum of seven switches.
Each switch has its own identity. This is unique for the relevant function. The switches can therefore be positioned in any location on the dashboard environment panel, as long as they are installed in the off position. They do not have to be in any particular order. However, the identity of the installed switches must correspond with the car configuration file so that they can be activated. For further information regarding the car configuration file, see Design and Function .
There are diagnostics for the switches.