Circuit/System Description

The Stop/Start System is used to improve fuel efficiency in stop/start driving. The engine control module (ECM) receives the voltage and current information from the BCM to determine if the battery state of charge (SOC) is sufficient to support a Stop/Start condition. If all necessary conditions are met (e.g. vehicle speed below 5 km/h (3 MPH), brake pedal depressed to keep the vehicle at rest etc.), the vehicle automatically shuts off the engine. When the Stop/Start System has shut down the engine, the ECM activates an auxiliary component to maintain proper transmission fluid pressure. The dual battery control module isolates the main and auxiliary battery, and the vehicle loads are supported by the main battery only. The engine restarts when the driver releases the brake pedal. During engine crank, the auxiliary battery is switched in by the DBCM to supply voltage to the vehicle loads. During engine crank, the primary battery is isolated from vehicle loads and supplies voltage to the starter motor only.