Regulating The Alternator (2005-)

Fig 1: Identifying Alternator Control Module (ACM), Engine Control Module (ECM) And Central Electronic Module (CEM) Communication

Courtesy of VOLVO CARS CORPORATION

The engine control module (ECM) (4/46) regulates the alternator charging voltage (via LIN communication) in response to a request from the central electronic module (CEM) (4/56) (via CAN communication).

The engine control module (ECM) can change the requested charging voltage from the central electronic module (CEM) in order to adapt it to certain operating conditions such as starting, idling or high engine loads.

The value requested by the engine control module (ECM) for charging voltage and alternator charging current can be read using VIDA (Volvo scan tool).

The alternator control module (ACM) sends fault information to the engine control module (ECM). Diagnostic trouble codes are stored in the engine control module (ECM).