Sentry Key Immobilizer System

Sentry Key Immobilizer System (SKIS) is designed to prevent unauthorized vehicle operation. SKIS components include SKIM, sentry keys and Powertrain Control Module (PCM). Sentry keys communicate with SKIM with an internal transponder located in plastic of sentry key. When ignition switch is turned on, SKIM sends a "challenge" signal to transponder in sentry key. Sentry key will respond to the "challenge" by responding to SKIM with encrypted secret key data. If secret key data matches stored data in SKIM, vehicle will be allowed to start. If secret key data does not match stored data in SKIM, SKIM will send a signal along PCI bus to PCM to zero-out fuel injector pulse-width and vehicle will not be allowed to start. Vehicle will start next time a valid ignition key is used.

Large metallic objects or items such as gas station speed pay devices on key chain may cause vehicle starting problems. SKIS cannot be damaged by these devices, but intermittent no-start conditions may arise. If a problem occurs, remove items from key chain and attempt to start vehicle again.