DTC P1632: Theft Deterrent System - Fuel Disabled: Description

WARNING: This page is about a different car, the 2002 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The Passlock(R) system is designed to prevent vehicle theft by allowing the ECM to disable the fuel injectors unless a correct key (voltage) code from the Passlock(R) sensor via the mechanical key is correct. The Passlock(R) system utilizes four components: the lock cylinder, Passlock(R) sensor, Body Control Module (BCM) and Engine Control Module (ECM). When the ignition is turned to run or crank, the BCM will look for a correct voltage code from the Passlock(R) sensor. If the correct voltage code is not received within a certain amount of time or is incorrect, the BCM will send a "fuel disable password" to the ECM over the CAN BUS. The SECURITY telltale will flash and the engine will not be allowed to start. If the BCM receives the correct code from the Passlock(R) sensor that it has stored in memory, it will send a password over the CAN BUS to the ECM. If the ECM Passlock(R) password it has stored in memory does not match the BCM password or if the ECM receives an undecided password from the BCM, it will allow the engine to start then stall within 4 seconds. The SECURITY telltale will flash for 10 minutes if the ECM receives an undecided, incorrect or fuel disable password. If the password to the ECM is correct, the engine will operate normally. The password is sent continuously by the BCM to the ECM with ignition on. If the password becomes lost or incorrect during the ignition cycle, the vehicle will be allowed to start on succeeding ignition cycles without the aid of Passlock(R) and the SECURITY telltale will be on steady. This mode is called fail enable mode.