Operation

OPERATION

SENTRY KEY IMMOBILIZER


The Sentry Key Remote Entry Module (SKREEM) receives an encrypted Radio Frequency (RF) signal from the transponder key. The SKREEM then decrypts the signal and broadcasts the requested remote commands to the appropriate modules in the vehicle over the Programmable Communication Interface (PCI) data bus. A valid transponder key ID must be incorporated into the RF signal in order for the SKREEM to pass the message on to the appropriate modules.


Automatic transponder key synchronization is done by the SKREEM if a valid transponder key is inserted into the ignition cylinder, and the ignition is turned ON. This provides a maximum operation window for RKE functions.


Each Sentry Key Remote Entry System (SKREES) consists of a SKREEM and a transponder key. Each system has a secret key code unique to that system. The secret key is electronically coded in the SKREEM and in all programmed transponder keys. It is used for immobilization and RKE functions for data security. In addition, each transponder key will have a unique identification. For North America, the options are a 3-button or 6 button integrated keys. For Export, the options are 2-button or 5 button key fobs. (Export does not get the integrated key).


When the ignition switch is moved to the RUN position, the SKREEM transmits an Radio Frequency (RF) signal to the transponder in the ignition key. The SKREEM then waits for a response RF signal from the transponder in the key. If the response received identifies the key as valid, the SKREEM sends a "valid key" message to the Powertrain Control Module (PCM) over the Programmable Communication Interface (PCI) data bus. If the response received identifies the key as invalid or no response is received from the transponder in the ignition key, the SKREEM sends an "invalid key" message to the PCM. The PCM will enable or disable engine operation based upon the status of the SKREEM messages. It is important to note that the default condition in the PCM is "invalid key." Therefore, if no response is received by the PCM, the engine will be immobilized after two (2) seconds of running.


The SKREEM also sends indicator light status messages to the Mechanical Instrument Cluster (MIC) to operate the light. This is the method used to turn the light ON solid or to flash it after the indicator light test is complete to signify a fault in the SKREES. If the light comes ON and stays ON solid after the indicator light test, this signifies that the SKREEM has detected a system malfunction and/or that the SKREES has become inoperative. If the SKREEM detects an invalid key OR a key-related fault exists, the indicator light will flash following the indicator light test. The SKREEM may also request an audible chime if the customer key programming feature is available and the procedure is being utilized.


REMOTE KEYLESS ENTRY (RKE)


After pressing the lock button on the RKE transmitter, all of the door locks will lock, the illuminated entry will turn off (providing all doors are closed), and the VTSS (if equipped) will arm. After pressing the unlock button, on the RKE transmitter, one time, the driver door lock will unlock, the illuminated entry will turn on the courtesy lamps, and the VTSS (if equipped) will disarm. After pressing the unlock button a second time, the remaining door locks will unlock. The Electronic Vehicle Information Center (EVIC) or the DRBIII(R) scan tool can reprogram this feature to unlock all of the door locks with one press of the unlock button. If the vehicle is equipped with the memory system, the memory message will identify which transmitter (1 or 2) sent the signal.


The SKREEM is capable of retaining up to 8 individual access codes (8 transmitters). If the PRNDL is in any position except park, the SKREEM will disable the RKE. The 4 button transmitter uses 1-CR2032 battery. The minimum battery life is approximately 4.7 years based on 20 transmissions a day at 84° F (25° C). Use the DRBIII(R) scan tool or the Miller Tool 9001 RF Detector to test the RKE transmitter. Use the DRBIII(R) or the customer programming method to program the RKE system. However, the SKREEM will only allow RKE programming when the ignition is in the ON position, the PRNDL is in park position, and the VTSS (if equipped) is disarmed.


TIRE PRESSURE MONITORING (TPM)


The SKREEM monitors the signals from the tire pressure sensor/transmitters and determines if any tire has gone below the low pressure threshold LOW TIRE PRESSURE THRESHOLDS table.


INDICATOR







CRITICAL AND NON-CRITICAL SYSTEM ALERTS


CRITICAL: A critical alert will be triggered when a tire pressure has gone below a set threshold pressure. The EVIC display will display "X TIRE(S) LOW PRESSURE". "X" will be the number of tires reporting low pressure. The message will display for the duration of the current ignition cycle or until an EVIC button is pressed. If the display is removed without correcting the condition, it will reappear 300 seconds to warn the driver of the low pressure condition.


NON-CRITICAL: A non-critical alert will be triggered when no signal is received from a sensor/transmitter. The EVIC display in the cluster will display "SERVICE TIRE SYSTEM SOON".