Entry Module System

The Viper Coupe utilizes a new Entry Module (EM). This system replaces the prior year Vehicle Theft Alarm and Remote Keyless Entry modules. The new module is located on the left side of the transmission tunnel, above the knee bolster. It is secured with a rubber strap. It contains a 32-way and two 6-way connectors. There is a green six way connector and a black six way connector. The module is connected to the CCD bus and transmits the "OK to run" message to the PCM when the theft alarm function is not tripped. It also receives the vehicle speed message from the bus. There is also a hard-wired backup circuit for vehicle speed.

The Entry Module provides remote keyless entry functions as well as vehicle theft alarm functions, electric locking/unlocking and the opening or power unlatching of the doors. The 1996 coupe utilizes power unlatching of the doors based only on inputs from the switches on the inside or the outside of the vehicle. The unlock button on the fob will not power unlatch the door. It also allows for the rolling lock feature, the only difference from other rolling lock systems is that specific throttle angle is not required for the locks to actuate. It is strictly a speed based system.

The Coupe will use new electric door latches to accomplish opening and closing of the vehicle doors and electronics to accomplish the lock function that was typically performed with linkage inside the door. The new system utilizes electric latches inside the door and switches both inside and outside the vehicle. These switches are inputs to the EM and if the conditions are correct, the EM will unlatch the door. The lock function is simply the ignoring of the switch inputs that would normally open the doors. There is no mechanical lock linkage inside the door. This results in fewer moving parts and problems associated with packaging the linkage mechanisms. The outside and inside door handles control micro switches that are the inputs to the EM. Located below the inside door switches are the lock rocker switches with LED indicators. The LED lock indicator informs the driver and passenger of the lock status of the doors. If the light is off, the doors are locked. Once the vehicle is started and driven approximately 8 mph (+/-3) the doors will automatically lock, therefore, the LED will be extinguished at this time. There is no defeat of the rolling lock feature. If there is no activity for approximately one minute (input to the EM) and the key is in the "on" or "off" position, the LED will be turned off to reduce battery draw.

The driver and passenger lock switches are wired in parallel and form one input to the EM. When the EM receives a lock input, both doors are locked. When an unlock signal is input to the EM, both doors are unlocked. If the key is on, and an inside door handle input is seen and vehicle speed is below 5 mph, both doors will be unlocked (and ultimately power unlatched). The lock switch is a momentary contact type switch and either switch will lock or unlock both doors. In case of an electrical failure that would render the EM system inoperable, there is an emergency mechanical release for the door located in the "B" pillar area of the door. This can be accessed through the Liftglass area. The only way to access the driver compartment of the vehicle once it is locked, (without setting off the alarm) is with the key fob. There is an exterior lock cylinder for the lift glass, that allows opening with the key. This cylinder is not equipped with a disarm function. If the Liftglass is opened with the key when the alarm is armed, it will set oft the alarm. There is a new Liftglass ajar switch that mounts on the left gas prop. When the Liftglass is opened, the outer shell of the gas prop allows a micro switch to close and the Liftglass ajar circuit is tied to ground. The EM monitors this circuit and knows the glass is open. If the Liftglass is broken, the prop will extend and trip the alarm. By utilizing a prop switch in this manner, the vehicle is protected against opening or breakage of the Liftglass.

The key fobs are unique to the Coupe 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. By pressing the lock and unlock buttons together, the system will re-synchronize. The system will respond with a horn chirp and normal operation resumes. This is not the same as programming a key fob.

The system will accept up to four fob codes and the system can be programmed with either the DRBIII or by connecting a programming wire to ground and placing the module in programming mode. If the system is set up for programming, all key fobs available for the vehicle must be programmed at the same time. When the module is placed in program mode, all the previous information from the transmitters is erased and no information is placed there until the system recognizes a valid key fob. Pressing both lock and unlock buttons on the key fob at the same time will cause the system to respond with a horn chirp after approximately ten seconds. Then any other transmitters may be programmed. There is a time out after approximately 60 seconds of inactivity (no further transmitter recognized). If the system times out, it will have to be returned to programming mode with either the DRBIII or by disconnecting and re-connecting the green programming wire located near the module connectors. The DRB "Theft Alarm Monitor Screen" contains information about how many fobs have been programmed. The horn chirp feature can not be disabled.

The security portion of the module performs typical security functions. The system can be actively armed by pressing the lock button on the fob. The system responds with a single horn chirp, if the message is from a valid (programmed) key fob. This information can also be accessed on the VTSS monitor screen with the DRBIII. The system will passively arm if the ignition is turned off and the key is removed, the hood and lift glass are closed, a door is open, pressing the lock button on the door and closing the door. There is a 15 second arming period. The security LED will turn on during the arming process and the horn will chirp on completion of the arming process. The security LED will then flash at a 10% duty cycle. The system can only be disarmed with a programmed key fob.

When the alarm is tripped, the park lamps and the horn will flash indicating that the vehicle has been tampered with. The alarm can be tripped by opening doors, hood, Liftglass or turning the ignition on. Once tripped, the alarm will sound for 2.5 minutes. The park and tail lamps will flash for approximately 18 minutes. The PCM will not allow the engine to start. If the EM has been tripped and 18 minutes have passed, the horn will chirp 3 times upon unlocking with the key fob to alert the driver that a theft condition may have taken place. Normal disarming with the key fob will result in two short horn chirps.

Diagnostics
The EM system is fully addressable with DRBIII or equivalent scan tool and it is the recommended method for diagnosis. The EM system does not display any Diagnostic Trouble Codes. All of the input switches to the EM can be read with DRB under the I/O screen. The doors can be unlatched with the DRB -- or scan tool -- under actuator tests. If the inputs are OK and the outputs can be cycled with the DRB, the problem is usually the Entry Module.

For testing procedures Testing and Inspection