Keyless Entry: Description and Operation

INTRODUCTION
The Viper utilizes a new Electronic Entry Module (EEM). The EEM provides Remote Keyless Entry (RKE) functions as well as opening or unlatching of the doors. The RKE system allows locking and unlocking as well as arming and disarming of the security system with a hand held radio frequency transmitter. The transmitter sends out a rolling code for high vehicle security.

Operation

Transmitter:

The transmitter has two buttons for operation. They are LOCK and UNLOCK. The UNLOCK button will unlock both the drivers and passenger side doors. Upon pressing the LOCK button, the horn will sound a short CHIRP to notify that the all door lock signal was received. The driver and passenger lock switches are wired in parallel and form one input to the EEM. When the EEM receives a lock input, both doors are locked. When an unlock signal is input to the EEM, both doors are unlocked. If the key is on, and an inside door handle input is seen and vehicle speed is below 8 to 13 Km/h (5 to 8 mph), both doors will be unlocked. The lock switch is a momentary contact type switch and either door will lock or unlock the entire vehicle. The key fobs are unique to the Viper and utilize a rolling code system. The rolling code feature changes the key fob message each time it is used. The key fob message and the receiver message increment together. Under certain conditions with a rolling code system, the receiver and transmitter can fall out of synchronization. The system will accept up to four fob codes.

Resynch Activation Of The Transmitter
The Electronic Entry system has a rolling code for the RKE system. The transmitter and receiver increment together. If the transmitter buttons are pressed more than approximately 255 times out of range of the receiver, the transmitter and receiver are said to be out of synch. In this case the transmitter will no longer operate. The transmitter and receiver can be resynched by holding both the LOCK and UNLOCK buttons down for a period of 5 to 10 seconds. The receiver shall acknowledge a successful synchronization by commanding a horn chirp. Normal transmitter function will return.