My pass key fault light keeps flashing on and off. Tried to crank it and it wont start. So I took it to the Chevy dealer and they told me it would be $685 to fix it cause something is wrong with my Anti-Theft Security Module. I think that is a little to much considering they are the ones who put a new Ignition cylinder in for me before this happen. Can somebody help me or give me some insight on this matter?

redux 1. see next post, 5.3L , 8COPS, 8 injectors, present and sea of sensors sure EFI.
we learned this.
5.3L engine.
not told if Passkey there.IMMO, it can not be IGNORED or hacked if there, RPO tells if it is there.
RPO codes tell what was on the car sold day 1, RPM is GMs name for AS _BUILT
RPO tells if car is IMMO opted. and matters first.

symptoms so far:
cranks ok
starts and runs and dies fast my guess 3seconds fast but not told
if dies, use right foot to prevent the stall, and post her if it did or not.

NO SCAN tool used is a very bad thing, on any modern car.
buy one , rent, lease, barrow one, or have car savvy friend scan yours.
I bet the tool tells you what fails

1: bad fuses. all must be checked on modern cars as lots of communications bus, can fail fuse blown.
2: engine compression pass.
3: scans show X,y, bad, tell what it finds, and we tell you what to check next.
eg: P0341, cmp dead. or ckp dead or error that says , they are out of sync,(timed wrong means0
4: fuel pressure not at spec cranked, , using gauge per SM
5: not reading the SM here.
https://eautorepair.net/Marketing/Default.asp


RPO? google how to read GM RPO codes and where found on car body.
glove box, console box lid, trunk lid, spare tire lid or drivers door jam, edge 3D bar code for RPO and GM app that reads it fast. and easy .

then see if IMMO codes is in list
AUO =Remote Function Actuation - Keyless Entry – Domestic
VATS, PassKey, and PassLock

DTC B3055, pass key failure DTC errors or B3935?
and more car cranks but alternator is dead and after it runs battery voltage is too low.
and sets a DTC for weak battery as it fails.
use a charger to keep battery fully charged and test ALT For dead. 13v to 15vdc is good running later when it does.

If your key has the black bump on the side of it, you can try to clean it. That is the resistor for the security system. The ignition reads that bump and if the resistance doesn't match, it won't start.

Do you have a security light flashing in the dash when you try to start it, does the starter spin the engine for but not start it up? Have you tried spraying fuel into the intake during cranking? Do you have spark? Any fault codes? All this can be the problem and other things as well, have them all eliminated as the cause.

Ypur security system is armed, if you was try unlock procedure from owners manual and wont work, its possible that you will need visit your dealer to reprogramming.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

Yes it sounds like a security system problem. Does the new column have pass key? You are leaving the key on until the security light stops flashing? The light is flashing for 10 minutes?

Yes. pass-lock has roughly a 10 minute timer.

Pass key is the security system which disables the car if it is stolen. You need the remote or a key with a chip to start the car. go to a dealer, prove ownership with registration and they will be able to help you out

WELL I HAD THE SAME PROB. ON A 95 CHEVY CAPRICE.I REMOVED THE IGNITION AND THE WIRE WAS BROKE.WHEN U TURN THE KEY THE PASS KEY WIRE TURNS WITH THE IGNITION,WHAT A FAULTY DESIGN.ANY HOW BUY A NEW IGNITION AND KEY THAT SHOULD SOLVE THE PROB. GOOD LUCK

I have a 96 Caprice and this has happened to me twice now. There are two wires that are behind the ignition (where the key goes) one or both of the wires have more thsn likely broken. I was told that the little chip in the key may have been bad so I had a new key made, didn't solve the problem!! Come to find out there was a guy in my area that rebuilds steering colums and ingnitions when there's a problem or someone tried to steal the vehicle. So I live in Dayton, Ohio hopefully your in the area probably not but try to find someone who works on cars in your area and have them take your ingnition out, and i'm about 90% sure that that is your problem. Hope it works for you. Kevin