Theory Of Operation

The hood ajar status is monitored using two switches for the Engine Stop/Start (ESS) equipped vehicles. Hood Ajar Switch one is integrated into the Hood Latch and is hard wired to the Body Control Module (BCM). The signal is sent to the Powertrain Control Module (PCM) over the CAN BUS. Hood Ajar Switch 2 is hard wired to the PCM. If the PCM detects that either switch is in the open position or is faulted for any reason, the ESS feature will be disabled during the current ignition cycle.