2004 Chevrolet Impala Passlock Issues

I have a 2004 Chevrolet Impala equipped with ”Passlock” factory Theft Deterrent System. Anyway​ for the past couple weeks SOMETIMES I can try to start my car and it won’t do anything. No crack or click or anything. Battery is good, changed the starter and checked fuses….etc.

After researching via Google I’ve learned that year of the Impala is known for major issues with the factory Passlock system. Someone suggested using a passlock bypass module, is that possible? Or can this probably only be fixed by installing a NEW ”KEY IGNITION?” PLEASE HELP!!!!!

Answer: Yes, this is a common problem with the Chevy Impala. No, a new key will not fix the problem. There are modules . kits to bypass the system totally. If you have a non-factory security or remote on the car, this can also cause problem in the GM Passlock theft system. Best to disable that before you try to fix your car.

Most likely the problem is in the ignition switch and cylinder in the dash. This is where the Passlock sensor sends it’s signal the the BCM (Body Control Module) to allow the car to start.

We have several article relating to this problem. Click this link for more information. GM Passlock Problems


I’m having a problem with the passkey lock and VATS security system. It’s preventing me from starting the the engine with the key. I have tried placing a switch and it didn’t work. What would be the best thing I can do to solve my problem ? 2001 Chevrolet Impala LS.

Your security system is not the older ‘VATS’ style. You have what is called Passlock. You cannot bypass it. You most likely need to replace the ignition cylinder and reprogram the theft deterrent.

And also I do not have the key with an chip. will that prevent or slow down that process ?

Your car does NOT require a key with a chip. The Passlock sensor is built into the ignition cylinder housing.

Is it a way I can reprogram the theft deterrent with out bringing it to an auto shop.

Yes it is something you can do yourself, but without a proper scanner, it is a 30 minute procedure.

Are you able to provide me with the steps ? If it Isn’t too much to ask.

I can provide you a link to the procedure, but we charge a small fee for that information. Just click the Donate button at the bottom of the chat box and I will get that to you right away, thank you.