Engine Stop Start System: Operation: Notes

The vehicles first engine crank event is managed by the driver acting on the ignition state and requesting an engine crank request. When this request occurs, the BCM cranking relay is opened and the PCM cranking relay is closed. When the engine is ON and the engine cranking phase has ended, the PCM cranking relay will now be opened and the BCM cranking relay will now be closed. All of the next automatic ESS cranking events managed in the same Key ON ignition cycle are performed maintaining the BCM cranking relay closed and setting closed the PCM cranking relay. Each time an ESS cranking event occurs which causes the engine to come on again, the PCM cranking relay is opened.

For ATX equipped vehicles, the PCM sends a signal to TCM to indicate it is ready for an ESS event, then TCM responds it is ready for ESS and enters a hydraulic neutral state while in an Auotstop event and stays in hydraulic neutral while Autocranking to avoid vehicle movement during engine cranking.

For MTX equipped vehicles, the PCM will initiate the ESS start event with a short press of the clutch pedal when the MTX is in neutral. The PCM will allow an ESS autostart event to occur while in a drive engaged gear if the clutch pedal travel goes past the interlock position. Otherwise the PCM will trigger an IPC display message to alert the driver to either press the clutch in or shift the transmission into neutral.