Current Limiting
Central electronic module (CEM) (4/56) communicates with the engine control module (ECM) (4/46) on the controller area network (CAN) The engine control module (ECM) communicates with alternator control module (ACM) (4/98). In this way the central electronic module (CEM) receives information about how much current the generator produces and how much current can be used for the various loads in the vehicle.
Under certain conditions the generator cannot produce enough current for those loads which are connected. The central electronic module (CEM) communicate with the with climate control module (CCM) (3/112) which then completely or partially switches off the following loads.
- electrical additional heater
- rear demist
- electrically heated seats
- heated door mirrors.
The central electronic module (CEM) also transmits a request via the Control area network (CAN) to the engine control module (ECM) to increase the engine idle speed.
When the engine is not running all current is taken from the battery. There are a number of different loads which can be activated when the engine is not running. For example the infotainment system. The central electronic module (CEM) continuously monitors the voltage level of the battery. When the voltage level is too low the central electronic module (CEM) transmits information to the infotainment control module (ICM) (16/1) which then shuts off the infotainment system. In the event of a fault, the central electronic module (CEM) transmits data via the Control area network (CAN) to the driver information module (DIM) (5/1) which displays a text message to the user.
If the infotainment system used in key position II, when the engine is not running, the information is sent to the driver information module (DIM). A message is displayed if the infotainment system is switched off for 2 minutes.