I have a 2001 Z06 that's been having issues with the ignition for a couple months. What happens is when I go to start it everything turns on like normal and looks like nothing it wrong. But once you turn the key to start it everything shuts off like there's no signal and you have to try it a few to a million times with one or both keys to get it to send the signal. Both of the keys work and once the car decides to start it starts right up without issue. I tried taking apart the ignition switch and cleaning the metal connectors like I saw on other threads to no avail. I even tried a new switch altogether with no luck. Then I was getting both of the VATS key codes for the BCM and realized my keys could be removed with the engine running. So I got a new key cylinder and had a locksmith program the new cylinder to my keys and I no longer get the BCM codes for the VATS. However, it hasn't solved my issue. It seems that mechanically everything is working fine at this point and it is somehow not sending the right signals when I try to start it. Some days it will work first try every time and other days it takes a million tries and attempts with both keys to get it to start. At this point I'm down to grounding or wiring, a fuse doesn't seem likely in this case.

 

The first area I would check is the battery. Have the battery load tested to make sure the battery is good. Next, the battery connections. Both CLEAN and tight? The FSM says 11 foot pounds of torque on battery side terminals. Probably not the cause, but in the past some batteries have been found to have shallow threads on side terminals, so that even when tight, the cable is not tight against the battery and can be easily moved on the battery by hand.

Next, grounds. There are a lot of them, all to the frame. If the problem persists after confirming the battery and connections are good, disassemble and clean, dielectric grease every ground.

 

Doubled checked the battery connections, they're nice and snug and the battery is a new Optima red top, so no issues there. I'll definitely have to get around to checking the grounds when I can.

 

When my ignition switch was on its way out I selected “volts” on the DIC..when I went to start the car I saw 8 volts during start...you can look at that...I had to cycle the key about 10 times and then it would start !!

 

The very first thing to check when you have a no crank problem is the TDR "Theft Deterrent Relay" it is located above the BCM in the passenger side footwell area where the fuse box is located. You should here the TDR click on when you turn the key to the start position every time. The TDR is the relay that sends power to energize the starter, so you must verify that the TDR is being energized, if it is, the starter solenoid/starter may have to be replaced, repost after checking and we can go from there.

 

So I can audibly hear the click from the TDR when I try to start the car, There is also a strange click sound when I turn the key from run to acc. On top of that the check engine light will stay on when the key is on run.

 

Attached a video of what happens when I try to start it.

 

Are you able to pull the codes? If you get power with the key in ACC position, you can get the codes. I couldn't open your video so can't answer my own questions.

 

Also are you able to read voltage on the instrument cluster when attempting to start?

 

Did you check the TDR relay as I suggested? Many people mistakenly believe that the car goes dead because the car fails to start when in reality the ignition switch contacts for systems that are not needed for the car to start are opened when the switch is in the start/crank position. From your description you may have a failing starter/solenoid, and that will not bring up any codes. Have someone strike the starter with a broom handle while you hold the key in the start position, if it cranks over your starter solenoid is the problem.

 

Sorry, I missed your post where you state that you do hear the TDR click, so yes most likely you will have to replace both starter and solenoid. The check engine light will remain on in run if the car fails to crank, that is normal, if the check engine light stays on when the car starts there is a code that has been set.

 

OP, my car does exactly this in exactly the way you described. Seems to do it more when it's actually what is considered cold out here in Southern California(at the AM, maybe 50 degrees roughly). I'll have it happen maybe once every few months. I noticed when mine does it that the steering column doesn't unlock. And if I'm remembering right, I'll occasionally see the 'security' light illuminated when it's going to pop up with it's rare occurrence of not turning on.

Only difference between mine and yours seems to be that I had read somewhere that it takes 2 minutes roughly for the security system to reset or something(I know I'm being extremely vague but I can't remember off hand what I originally read it as). At first I thought maybe it was my aftermarket alarm starting to act up, then vats key, etc. I would lock and unlock the car via remote, via door switches, everything you could think of. After 2 minutes of waiting, I'll put the key in, and can hear the column lock disengage and the car will turn on without issue. The video you posted is literally what happens in mine, EXCEPT, I think I remember that I can hear there is no fuel pump priming, which always made me think it's part of the security system somewhere, and the immobilizer or something not allowing the car to get that far of allowing the fuel system to prime in preparation of turning on. Once the 2 minutes have passed, in addition to that column lock disengaging, the fuel pump will now prime which can be heard audibly and I'll get going.

I've even got the same year Z06 as you. No check engine light, or code is thrown when it gives me this error. Not via a reader, or through the history when going through the DIC for codes.

Since it's such a rare thing to happen to me(so far I've had it happen 2, maybe 3 times in the last 6 months if that) I have just ended up leaving it alone, especially since it's consistently just a 2 minute wait when it has happened. I do plan on getting my EBCM fixed eventually because that's the only thing that I occasionally have act up, but that's the only thing I have on my car that acts up occasionally(just a quick CEL that I clear on the rare occasion that one pops up).

 

Oh, and forgot to mention that when I first had the issue pop up(bought the car at around 73k miles, I wanna say it started happening around 85k miles), I went through and checked every single ground and connection, as well as applied dielectric grease to them. Did the usual cleaning of the ignition, the vats pellet, key itself, etc. Nothing ever seemed to give me a specific cause or have any effect on when it would do this. At this point I just chalk it up to just being one of the many weird electrical gremlins we get on the C5.

I did get a new starter put on around 74k miles, and I want to say I may have installed my new alternator somewhere around the 85k mile mark, but can't be 100%. I know some alternators give the occasional Charge System Failure warning if you don't get the exact specific one for your model C5(the earlier ones were more sensitive than the 02+ IIRC which are less prone to acting up if the exact right one isn't used), and I want to say our 01 models didn't use a hugely different one, but I remember needing to have the alternator having some kind of regulator or something that sends a signal when it's activated to kind of give an 'all clear' signal back to the car and stop it from giving the Charge System error on the DIC. My car will very rarely give me the Charge System Failure maybe 2 times a year since I've installed it. I know they aren't connected(ignition and alternator), but the timing has always seemed a little to coincidental to me and I figure alternator giving that occasional error to the electrical system could maybe make something else act up(in this case the security/ignition). But like I said since neither really causes me any headaches when they rear their head once in a blue moon, I'm just waiting til the next time I may need an alternator and I'll go through with getting a different alternator and see if maybe that solves both issues)

 

There are other things to try before replacing your cars starter/solenoid, you could replace the TDR, the contact's may have become dirty, it's inexpensive and plug and play. The other thing to check is the cable connections at the starter solenoid, make sure they are clean and tight. Hope this helps.