Hands-Free Start Power Modes

The 2024 Silverado EV and Blazer EV are equipped with Hands-Free Start, which automatically starts the vehicle when the driver enters the cabin with a remote key fob and then presses the brake pedal or closes the door. A message will display on the Driver Information Center stating how to turn on the vehicle as a reminder to the driver. Plus, a Vehicle Ready indicator will illuminate on the instrument cluster, indicating the vehicle is in propulsion mode, and an active battery gauge will be displayed when the vehicle is ready to be driven. (Fig. 4)

 

Fig. 4

 

Power Modes

The Body Control Module (BCM) is the Power Mode Master and uses various vehicle status conditions and inputs to determine the desired vehicle Power Mode state.

With Hands-Free Start, there are three power modes:

• OFF (Vehicle OFF) – A low-power mode that allows maximum stand time until the next start request. All features are disabled, and propulsion is inactive.
• RUN (Service Mode) – All features are enabled, but propulsion is inactive.
• PROPULSION (Vehicle ON) – All features are enabled, and propulsion is active.

Vehicle OFF

When the vehicle is shifted to Park, the vehicle will turn off when a driver exit is detected. The driver must unbuckle the seat belt, release the brake pedal and open the driver’s door in order for the vehicle to power off. Retained Accessory Power (RAP) will remain active until the driver’s door is opened.

If the vehicle has not been shifted out of Park, it will not turn off based on driver-exit detection and will need to be turned off using the virtual OFF button on the infotainment screen (Fig. 5) or by waiting for the automatic power mode time out.

 

Fig. 5

 

During some programming events, the virtual vehicle OFF button on the infotainment screen may not be available. In order to turn the vehicle OFF in this condition, close the driver’s door, depress the brake pedal and then place the vehicle in Drive for 3 or more seconds. After a few seconds, place vehicle back in Park, release the brake pedal and then open the driver’s door.

Service Mode

To enter Service Mode, the vehicle must be off with the driver’s door open and the remote key fob in range. The brake pedal should not be applied. Press and release the accelerator pedal three times within 5 seconds and keep the accelerator pedal pressed down the third time until the vehicle enters Service Mode. Service Mode is identified by the red icon on the instrument cluster. (Fig. 6) While in Service Mode, the driver’s door can remain open or be closed to complete any diagnostic procedures.

 

Fig. 6

 

The vehicle will not shut off after the driver’s door is opened and then closed while in Service Mode. To turn off the vehicle, it will either need to be turned off by using the OFF button sequence on the infotainment screen or by placing the vehicle back into Propulsion Mode and then using the driver exit steps mentioned previously.

The remote key fob must be out of range to remain in Service Mode while performing any procedures that require brake pedal application.

If the brake pedal is momentarily pressed while the remote key fob is in range, the vehicle will exit Service Mode and immediately enter into Propulsion Mode (Vehicle ON/Propulsion Active).

TIP: The automatic power mode time out and enhanced battery saver mode are disabled when in Service Mode. A low or dead battery may result if the vehicle is left in Service Mode for an extended period of time. The vehicle should only be in Service Mode to support ongoing vehicle diagnostics.

Propulsion Mode

To enter Propulsion Mode:

• With the vehicle OFF, open the driver’s door, and then either press the brake pedal or close the driver’s door with the remote key fob in range.
• With the vehicle in Service Mode, press and release the brake pedal while the remote key fob is in range.

If the remote key fob is left in range after turning the vehicle OFF, it will not enter Propulsion Mode again when opening and closing the driver’s door. The vehicle will only enter Propulsion Mode again after the brake pedal is pressed. In addition, if the remote key fob is not moved for 1 hour, it will become inactive and the vehicle will remain off after opening and closing the driver’s door or pressing the brake pedal.

Automatic Power Mode Time Out

If the vehicle is left stationary and not shifted out of Park or the brake pedal is not pressed while in Propulsion Mode, the vehicle will automatically turn off after approximately 60 minutes. The time out system is designed to prevent the 12V and high-voltage batteries from depleting in the event the vehicle is left on while unattended. The Power Mode Master is responsible for turning off or transitioning the vehicle into a lower parasitic sleep state. If any of the conditions are not met and/or if there is a change in the Park position or brake pedal status, the timer will restart until all of the conditions are met again.

For additional information about the Power Modes, refer to the appropriate Service Information.

– Thanks to Bill Taylor and Chris Semanisin