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

Notes and Comments

In more than 95 percent of the cases, if your security light is illuminated, and you can get your car started by waiting the 10 minutes, the procedure described here will cure the problem, your security light will go out and never come on again. In rare cases, there could be other problems which cause the "SECURITY" light to flash or stay on. Most common are:

  • Partially broken wires
  • Corrosion in connectors
  • Water having entered the Body Control Module
  • Dampness in connectors.

The first thing you will want to do is check your Body Control Module. In most GM Compact Cars, including the Grand Am and Alero, the Body Control Module is located under the glove box behind a removable kick panel. Take out the kick panel and you will find something that looks like this: (the center connector will be plugged in)
Location of the Body Control Module under dash on passenger side

  1. Disconnect all three connectors from the Body Control Module.
  2. Remove the Body Control Module by sliding it to your right. It takes a little effort, but it will come loose. Inspect the connectors carefully to make sure they are not corroded. Shake the unit and listen for water inside.
  3. If there is no problem with the Body Control Module, slide it back in place, making sure it is secure in it's mount.
  4. Inspect the three connectors on the wiring harness to make sure all contacts are clean and not corroded.
  5. If the car was starting correctly before you began disassembly, it is 90% safe to assume that the Body Control Module is functioning correctly. (Nothing is a sure thing!). Re-connect the two outside connectors to the Body Control Module. Leave the center connector hanging down.
  6. Disconnect the battery. Remove the radio again, and remove the tape and shrink wrap from the resistor you soldered in place. Find the yellow wire that goes to one of the pins on the center connector of the wire harness connected to the Body Control Module. With an Ohmmeter, check for continuity between the yellow wire in the radio compartment and the connector pin that the yellow wire leads to. The Ohmmeter should read near 0 ohms. If not, your wire is broken and you will need a wiring diagram for your vehicle to repair the wire.
  7. Check for continuity between the black security wire in the radio compartment and any pins on the center connector that have black wires connected to them. You should find at least one 20 gage black wire that measures near 0 ohms. If not, the black wire is broken, and you will need to obtain a wiring diagram for your vehicle to repair the wire.

The above constitutes almost everything I know about the Passlock II Security system on GM vehicles. If you can't fix your "SECURITY" light problem with this information, I'm afraid you're going to have to bring it to a dealer and spend a wheelbarrow full of money to have them look at it. It may help to print out a copy of this website and bring it along so the GM mechanic can familiarize himself with the Passlock II system. Most of them haven't the foggiest idea how the system works. If you find one who does, E-mail me with the dealer's name, and the name of the mechanic. We should give him credit for knowing more than any other GM mechanic on earth.

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