The hybrid control module (HCM) uses the hood switch signal to monitor the open or closed position of the hood for hybrid system function. The hood switch indicates the state of the vehicle hood, either open or closed. The hood switch output signal is an input to an HCM. Five volts is supplied to the switch, the returned voltage is measured relative to HCM signal ground to determine the switch state. A resistor network in the switch circuitry ensures that shorted high and low states can be diagnosed successfully. There are 2 valid voltage ranges of the return signal, one representing hood open, the other representing hood closed. If the voltage is lower than a threshold, a short low is indicated. Similarly, if the voltage is greater than the short high threshold, a short high is indicated. If the voltage is not high, low, open, or closed, then the state invalid is indicated. Driver Notification - Hood Ajar is used to request the instrument panel cluster (IPC) to display or clear the Hood Ajar message on the driver information center (DIC). This message will be displayed by the IPC until the driver acknowledges the message e.g., via the IPC Stem, Trip, Fuel, Personalization or Select buttons on the Steering Wheel or until requested off by the HCM via GMLAN message. The HCM shall not request the message to be displayed again until the next ignition cycle if the conditions for setting the message still exist unless or until the hood transitions back to closed and then back to reopened.

This diagnostic procedure supports the following DTC:

DTC B3009 Hood Ajar Circuit High

Ensure there are no obstructions underhood to prevent the hood from closing securely.