Principles of Operation

Locks, Latches and Entry Systems






Principles of Operation

NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).

Power Locks

The SJB monitors the door lock control switches. When the SJB receives an unlock/lock command from either door lock control switch, the SJB energizes a relay (internal to the SJB) to supply the correct power and grounds for the door lock actuators.

Keyless Entry Keypad

The keyless entry keypad provides a method for the customer to access the vehicle without a key or Remote Keyless Entry (RKE) transmitter. The keyless entry keypad feature:

- Locks all the doors
- Unlocks the driver door
- Unlocks all the doors
- Programs/erases a personal entry code
- Enables/disables the autolock feature
- Enables/disables the auto-unlock feature

When a keyless entry keypad button is pressed, the keypad buttons illuminate to provide better visibility. If the 7/8 and 9/0 buttons are pressed, or 5 seconds have elapsed since the last button press, the illumination turns off.

Vehicles equipped with a keyless entry keypad are programmed with a factory set 5-digit entry code. This code is provided to the customer on a wallet card in the Owner Literature package. In addition, this code is available through the use of a scan tool, and is printed on the SJB label located on the back side of the module (installed position). When entering codes, each digit must be entered within 5 seconds of the previous button press.

Anti-Scan Feature

To provide added security, the keyless entry keypad is disabled for 1 minute after pressing the keypad buttons 35 times without a valid entry code being entered. The keypad illumination flashes during this 1-minute mode. All functionality is disabled except for buttons 7/8 and 9/0 being allowed to lock the vehicle.

Remote Keyless Entry (RKE)

The SJB receives input from the programmed RKE transmitters. Based on input from the RKE transmitter, the SJB:

- Locks all doors
- Unlocks the driver door
- Unlocks all doors
- Activates/deactivates the panic alarm
- Turns the interior lamps on (when unlocking) and off (when locking), provided the defeat switch on the dimmer switch is not active
- Sounds the horn once when LOCK is pressed twice within 3 seconds, and the doors are closed
- Sounds the horn twice when LOCK is pressed twice within 3 seconds, and any door is open