PASSLOCK(tm) SYSTEM

WARNING: This page is about a different car, the 2002 GMC Savana, 2002 Chevrolet Chevy Express, 2001 GMC Savana, and 2001 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.

The Passlock(tm) system is designed to prevent vehicle theft by disabling fuel injectors causing engine to stall immediately after starting, unless a mechanical key is used to correctly engage and rotate the Passlock(tm) lock cylinder. Ignition lock cylinder fits inside the ignition lock cylinder case and operates ignition switch when turned by a key with proper mechanical cut. When ignition key is used to turn ignition lock cylinder to START position, a magnet on the lock cylinder passes close to Passlock(tm) sensor within ignition lock cylinder case and produces an analog voltage code in Passlock(tm) sensor. Passlock(tm) module compares voltage code to previously learned voltage code. If codes match, a class 2 message is sent from Passlock(tm) module to Powertrain Control Module (PCM). The message enables the fuel injectors.

If a magnet from outside of the ignition lock cylinder case is used to attempt to steal the vehicle, tamper Hall Effect sensor will be activated. This completes a circuit from security sensor signal circuit through a tamper resistor to security sensor low reference circuit bypassing the security resistor. If ignition switch is forced to rotate without correct key, or if ignition lock cylinder is removed by force, Passlock(tm) sensor will be damaged and will not operate. The components of the Passlock(tm) system are as follows:

The ignition lock cylinder and key
The ignition lock cylinder case including the Passlock(tm) Sensor
The ignition switch
The theft deterrent control module (Passlock(tm) Module)
The security indicator (on the instrument cluster)
The powertrain control module (PCM)