Ignition Cylinder Replacement Info

[SBCv8]

Happy New Year everyone!

The ignition cylinder on my 2004 Tahoe with 177k miles is becoming more and more difficult to get into the start/run position.

I've had a new key cut but that wasn't any help. (Turning the wheel left\right doesn't help either, it's definitely a worn cylinder)
The replacement part is only $30-$50 depending on the source.

My dilemma is that confirming whether or not this truck requires a "relearn" process for the new key package.
Also, can I use a thumb-wheel type ignition or will I need to replace it with the standard flat\round type?

I've already searched the forum and was surprised this question isn't in the main "How to" sticky thread as I'm sure it's a common maintenance part for this year vehicle.

I really appreciate any input or even a link if it offers some definitive answers.
Thank you very much! -Chris

 

[fiatdale]

I've replaced a lot of cylinders, housings and switches on these trucks. I've had them hit or miss for programming. Programming the pass lock can be done at home, but be prepared for it to fail and be towed to the dealer.

The way you program it: install the new cylinder by removing the upper and lower column trim, insert key into cylinder and turn almost all the way to start. There is a hole in the top of the hoisting, you'll need a pic tool or small screwdriver to insert and hit the release for the cylinder. It's best to do it with the battery unplugged so you don't crank it over. You'll feel the release button with the screwdriver, when you do, pull the key and assembly out.

You can disassemble the cylinder yourself and put the new tumblers in (they come with the kit). Each one is labeled with a number / letter so you know what to put where. Just do one at a time. Pull one out of the old one, put the matching new tumbler into the new cylinder.

Don't attempt to crank the ignition switch backwards while the cylinder is out. The last thing you want to do is not have it clocked right.

Once it's in, reconnect the battery. Turn the key to the run position. Leave it on (without starting) until the security light on the dash goes out. After some time, maybe 30 minutes the light will go out. Turn the key back, then turn it back to run. Wait for the light to turn off, then do that process one more time. After the 3rd time attempt to start the vehicle. If it starts and there is no security light on, you're good to go. Pm me for any questions, or I'll give you my number and I can walk you thru it.

 

[SBCv8]

Yeah that Passlock thing has me worried but my ignition is getting pretty crappy.
Sometimes it takes me several minutes to jiggle the key to get it turning.

I found some info about obtaining the stored resistance and basically fooling the Passlock module by putting in a matching resistor feeding back to this BCM. Hopefully that's not needed.

Do you know if just changing out the tumblers would change the resistance values and set off the Passlock?

If not that seems like the way to go.
Just swap in the new tumblers and put all the stock parts back in.

I appreciate the input very much!

 

[fiatdale]

New tumblers and springs shouldn't mess with it.

 

[SBCv8]

So I have not had any luck with this ignition security system.
I replaced the cylinder to test to see what would happen, no go. Start and stall result.

What's crazy is that my security light doesn't come on after the stall.

The procedures I have found\attempted are:
1.Start vehicle, stall, wait 10 minutes,(wait for sec. light to stay on solid) then immediately start from On position.
2.Start vehicle, stall, wait 10 minutes,(light will disappear), turn off for 5 seconds, then start the truck.

Neither have worked.

The security light never turns ON. It flashes after the truck stalls but that's it, no other flashing or constant light afterwards. *I've waited up to 20 minutes

Any ideas? Can someone tell me what system I have?
Is it Passlock2? *2004 Chevy Tahoe

At this point I replaced the ignition cylinder with the OEM part and it starts again.
Thank you.

 

[fiatdale]

Pass lock 2. Like I said, it can be hit or miss on if it needs to be programmed. I've had some that work right off the bat switching cylinders and others that need a tech2 to program. Yours may be in the latter group.