Page updated on 04-24-2018

anti theft

09-21-2005, 09:04 AM
can i unhook the anti theft on a 97 malibu???

09-22-2005, 11:09 AM
Are you talking about passlock?

12-14-2005, 09:39 PM
..or a '98 Malibu PassLock? How do I disconnect or disable it?

12-17-2005, 11:28 AM
..or a '98 Malibu PassLock? How do I disconnect or disable it?

You have Passlock 2.Here's some info for you that I have compiled. The easiest way is just to cut the yellow resistance wire and tape it up. Here is a wiring diagram for your car:

My security light started coming on again about a year after paying the dealership $450 to replace a faulty Ignition lock cylinder. I was at my wit’s end. My wife and kids would be stuck at night in some shopping center parking lot waiting 10 minutes to reset the Passlock Security. I was able to Bypass, Disable or Ghetto Hack my passlock II anti-theft system on my 2002 Oldsmobile Alero without relays or resistors. I had my local Auto wiring tech install a $5 on/off toggle switch under my dash that is connected into the yellow (key resistance/code/recognition) wire that can be cut (while the engine is running) to essentially bypass passlock I(1) or II(2) permanently.(I do not have nor intend to install a remote starter and I do not have an alarm on this car.) The toggle switch idea came about because of my concern that a dealership tech could possibly reset the security “fail- enable” mode or the battery could die or become disconnected for an extended period of time and reset the intended fault. All I need to do is flip a switch to break the circuit again while the car is running to take the passlock system offline. When the system is offline, the security light is on constantly.(Not flashing.) I don’t mind the light, but others may want to remove the bulb or black it out. Here’s how the setup works:
1)Switch On while engine is running – Security system is on.(Factory Setting) Security light is off. (Circuit is complete.)
2)Switch Off while engine is running – Security system goes into “fail-enable” mode and bypasses the passlock system. Security light is illuminated.(Circuit is broken.)
3)Switch On while engine is off – Security system is on (Factory Setting)(Circuit is complete.)
4)Switch Off while engine is off – Security system detects this as a theft attempt.(Circuit is broken.) If you try to start the car, the fuel will be disabled and the security light will flash.
Flip the switch On to complete the circuit and reset the security system to Factory setting. The car will now start.(Acts as a FUEL KILL SWITCH.)
Below you will find a thread and some supporting evidence of why this bypass actually works. The entire job took 25 minutes. There is an incredible link below with high resolution pictures of the wiring for your specific car. I included the actual photos that I used to gain access to my ignition lock cylinder wiring. *Special note: those with GM Class II Data Bus should leave your radio connected during the entire procedure so nothing weird happens. If you are unsure if your car is so equipped, it’s best to leave the radio connected and let it hang. Good luck and post with your success stories! 12/4/05 Is this You? Get in your car....try to start it and find that the passlock II is screwed up again, you have to wait 10 minutes for it to reset. When it resets it starts up and runs fine. Fix-------Start the car, find the yellow wire that I'm sure you've read about, the rcode wire that is, and cut it. Shut off the car and you're done! The rcode wire on my 2001 alero is behind and to the left of the radio, you must take out the radio.....the yellow wire accompanies two other wires, the white and black, the 3 wires are alone and run inside what appears to be a cheap electrical tape that will fall apart in your hand when you start tugging on it, they are very thin wires, maybe 18 to 22. I taped off both ends of the yellow wire too.Took me about 14 days to find this out and reading no exageration 1000 posts. Forget all the relay, DEI and resister crap that I'm sure you've read about. All this writing assumes that this will continue to work.....i WILL be back here to post an update if it fails again. If you have doubts of me coming back to update a failure you can email me page 4, The PASS Key Module also has the ability to allow engine operation if it recognizes a system fault in the ignition key reference circuit while the engine is running. In this case the Module enters and remains in a mode which allows the engine to be started and run without reading the resistance chip. This mode requires that the original factory resistance chip key be in the ignition lock
cylinder at the time the fault occurs. During this mode, the
security light will be ON all the time. When the key reference circuit is repaired, the module will automatically reprogram itself to the mode requiring the original resistance chip. page 3, If the correct key is in the cylinder and that circuit
fails while the engine is running, this is considered a
malfunction, not a theft attempt. The “Security” light
may turn on to warn of a system malfunction, but even if
it doesn’t, a key recognition circuit failure with the proper
key in the lock will cause the TDM to enter what GM
calls a “fail-enable” mode. Essentially, the theft-deterrent
system goes offline and the engine will start and run
with any key that turns the lock. and click on vehicle wiring diagrams to select your particular make.

The Ignition Lock Cylinder is the same for the following through the years noted:

1999 - 2004 Alero
1997 - 2003 Malibu
1999 - 2004 Grand Am

The GM part number is 12458191.

BTW - The cylinder is part of the Passlock security system. So a key relearn may be required if you replace it.

Add your comment to this topic!