Circuit Description
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. Hood Position Condition Met indicates that the hood position, as read by the HCM, meets the HCM requirements for entry into idle engine off (IEO) hood closed. 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.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B3008 Hood Ajar Circuit Low
Conditions for Running the DTC
| • | The ignition is ON. |
| • | The auxiliary power outlet (APO) switch is requested ON. |
Conditions for Setting the DTC
| • | Hood Position Condition Met indicates that the hood position, as read by the HCM, meets the HCM requirements for entry into IEO hood closed. |
| • | Hood switch voltage is greater than 4.95 volts. |
| • | HCM run time is greater than 5 seconds. |
Action Taken When the DTC Sets
| • | The HCM will record the operating conditions presents when the DTC set as Failure Records data only. |
| • | The IPC displays a hood ajar message. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
Conditions for Clearing the DTC
| • | The Conditions for Setting the DTC are no longer present. |
| • | A history DTC will clear after 40 malfunction-free ignition cycles. |
| • | The HCM receives the clear code command from the scan tool. |
Diagnostic Aids
Ensure there are no obstructions underhood to prevent the hood from closing securely.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Starting and Charging Schematics Connector End View Reference: Engine Electrical Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 |
Does the scan tool display open? | Go to Step 3 | Go to Step 4 |
3 |
Does the hood switch status parameter change state? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 4 |
4 |
Does the scan tool display normal state? | Go to Step 7 | Go to Step 5 |
5 | Test the reference circuit of the hood switch for a open or short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 6 |
6 | Inspect for poor connections at the harness connector of the HCM . Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 8 |
7 | Inspect for poor connections at the harness connector of the hood switch. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 9 |
8 | Replace the HCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 10 | -- |
9 | Replace the hood switch. Refer to Hood Primary and Secondary Latch Replacement . Did you complete the replacement? | Go to Step 10 | -- |
10 |
Does the DTC reset? | Go to Step 2 | System OK |
