GM Passlock Security Fix

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GM Passlock System
Tools and Supplies
1 - Disassembly
2 - Bypassing the Ignition Switch Security Circuit
3 - Reassembly & Recalibration

GM Passlock Bypass
Author- Richard M. Berger
All rights reserved
Following the instructions in this writeup will save you over $300.00 If this article helps you fix your GM Passlock Security Problem on your Pontiac Grand Am or Alero, put two dollars in an envelope and send it to:
Security Fix
1131 Outer Drive
Fenton, MI 48430


NOTE: 6/7/2011 - The PREFERRED method of doing this fix .... NO SOLDERING REQUIRED can be found here:

This article describes how to bypass the "Passlock Security System" on several models of GM cars. CAUTION - If you decide to do this modification, read this entire article thoroughly, and perform every step. Do not leave out any of the steps. I repeat.... Do not leave out any step.

The Problem

You try to start your GM car. The engine starts, but dies in one or two seconds, and the "SECURITY" light begins flashing.

OR ... You are driving along, and for no apparent reason, the "SECURITY" light comes on solid and stays on. After you shut down your vehicle, the next time you start your car the SECURITY light is on solid.

This is a common problem on the following GM Cars
1999 - 2004 Oldsmobile Alero
1997 - 2003 Chevrolet Malibu
1999 - 2004 Pontiac Grand Am

The problem is usually caused by the Security Module, which is part of the Ignition Lock Module. Your owner's manual gives you the following advise

"After attempting to start the engine, if the SECURITY light flashes or stays on, wait ten minutes with the key in ON until the light goes off. Then turn the ignition to OFF before attempting to start the engine again."

This works! Unfortunately, a few weeks later, you will probably have to go through the entire routine again. It will get under your skin really bad the third time, and after that, you will start kicking the dash and swearing. The menu to the left will guide you through the steps necessary to bypass the Passlock Security System on a 2003 Oldsmobile Alero, and keep the "SECURITY" light off forever. The steps necessary are similar on the other models listed above. There are generally only minor differences in how to get the radio out to get to the wires.

In GM cars, there is a bundle of three wires which go from the Body Control Module to the Ignition Switch. They are Black (analog return), White (power), and Yellow (analog data). The Yellow wire is circuit #1836, and this is the wire that furnishes an analog signal to the Body Control Module to tell it that a key has been used to turn the lock cylinder to the ON position.

The three wires can be accessed by removing the radio from the dashboard, and reaching through a hole in the radio compartment toward the steering wheel. This article describes how to reach these wires and modify the circuit to bypass the security module in the ignition switch.

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