Initial Inspection and Diagnostic Overview

SENTRY KEY IMMOBILIZER SYSTEM
The Sentry Key Immobilizer System (SKIS) performs a self-test each time the ignition switch is turned to the ON position, and will store fault information in the form of Diagnostic Trouble Codes (DTC's) if a system malfunction is detected. The SKIS can be diagnosed, and any stored DTC's can be retrieved using a DRBIII scan tool. Refer to the appropriate diagnostic information.

The Sentry Key Immobilizer Module (SKIM) has been programmed to transmit and monitor many different coded messages as well as PCI Bus messages. This monitoring is called "On-Board Diagnosis".

Certain criteria must be met for a diagnostic trouble code to be entered into the SKIM memory. The criteria may be a range of Input voltage, PCI Bus message, or coded messages to the SKIM. If all of the criteria for monitoring a circuit or function are met and a fault is sensed, a diagnostic trouble code will be stored in the SKIM memory.

The SKIM also sends SKIS indicator status messages to the EMIC. This indicator status message tells the EMIC to turn the indicator ON for about 3 seconds each time the ignition switch is turned ON, as a bulb test.

The SKIM sends indicator status messages to the EMIC to turn the indicator OFF, turn the indicator ON, or to flash the indicator ON and OFF. If the SKIS indicator flashes upon ignition ON or stays ON solid after the bulb test, it signifies a SKIS fault.

If the SKIM detects a system malfunction and/or the SKIS has become inoperative, the SKIS indicator will stay on solid. If the SKIM detects an invalid key or if a key transponder-related fault exists, the SKIS indicator will flash.

If the vehicle is equipped with the Customer Learn transponder programming feature, the SKIM will also send messages to the EMIC to flash the SKIS indicator and to generate a single audible chime whenever the Customer Learn programming mode is being utilized.