DanielRicany

Hello everyone. I'm helping a friend with a 1995 Corvette. He went to have a spare key made and is having some problems. We went back to the lock smith with our complaint and they made another key and still having the same problems.

What happens is if you use the new key to try to start the engine, the starter doesn't crank, and you can't use the old key to start it. You have to wait a few minutes before the old key will work again. Also on a scanner while the car is disabled, the scanner displays "No communication". But after the car is enabled again, if you use the original key it will connect to the computer.

I used an ohmmeter on both key resistors. Surprisingly both were the same at 0.88X kOhms.

But for some reason the car just doesn't want to cooperate with the new key. Does anyone have any idea what is going on?

Thanks!

1984Z51auto

My bet is that the "new" keys are not contacting the terminals in the ignition switch and therefore the security system is locking you out. Try cleaning the new key and try inserting the keys into the ignition with some contact or tuner cleaner on the "chip" contacts to clean the ignition switch contacts. This issue is not uncommon on GM vehicles of this period.

antfarmer2

DanielRicany

Thanks that's what I was thinking also. I tried what you said but it still didn't crank. I looked inside the cylinder and it looks like the one contact terminal is recessed. Maybe we can try to pry it outward a little bit.

WVZR-1

What was the reason for the new key? It wouldn't crank with the old or ....

If it didn't crank before, was it an intermittent problem or just quit all at once? A4 or 6MT?

DanielRicany

Well my buddy wanted to have a spare set of keys as he just recently purchased the car. Everything is 100% with the original key. And it's an A4.

hcbph

Same situation but this wasn't the solution. Helping a friend out with a Buick and had a key made as she only had one. Exact same symptoms. Grabbed an ohm meter and turned out they cut it on the wrong key blank. Grab an Ohm meter and check both the original and the replacement. Got another one made, they admitted the blank was in the right slot but was the wrong blank.

WVZR-1

Well kind of but ...

This car ran and drove fine it seems, made a key and it doesn't and it has to go through the "time out" to be able to use the OLD original, they returned to the shop and the guy made another key just like the one he did the first time that was wrong. The read of the original key seems to be wrong or a packaging problem with the keys .

The OP seemed to imply that the keys were of the same resistance and you would have assumed he meant old and new but seems he was talking about BOTH news.

If they mentioned to the LS that the old didn't work until the "time out" he should have realized his error.

At least it seems after a couple reads that this is the problem.

**** At this point what I'd do is take the old and a new to a dealer and let them drop the old and the new in the "Interrogator" and let the Interrogator decide the issue. OP - do you have two or three keys? What is the "branding" on the head of the key? Maybe on the old that worked and also the new.

DanielRicany

The ohm readings were between the new key and the original key. They are both the same reading. And it still starts with the original key after the timeout.

c4cruiser

How about trying to clean up the two blades of the resistor on the key using some very fine grit sandpaper (600 or 800 grit) or emery cloth? Could be that something on one of the blades aren't allowing a good contact. Just go very easy using a sanding block and then clean the surface with some acetone or lacquer thinner.

If the resistance value of the new key exactly matches the key that does work, there's no reason why it should not start the car.

WVZR-1

I was about to edit my last post and mention that it wouldn't be impossible for what you just mentioned to happen. It's maybe not even unusual. I had a car 10 -12 weeks ago that the old key wouldn't read in an Interrogator but functioned well in the car. The owner assumed that since the key didn't register there was a "bypass" involved so he bought the only VATS key that was available in the area assuming it would work. It didn't and after checking the car there had been no bypass.

Also if it's an aftermarket key and the "resistor" isn't centered in the key it's going to miss one of the contacts in the cylinder. That happens but not often. You got a pair - I asked the branding on the key head. What is it?

DanielRicany

Doesn't have a name, just says "For GM cars".

antfarmer2

sounds like the chip is not located right or two thin.

WVZR-1

You want an OE/GM, Briggs & Stratton or STRATEC key blank.

hcbph

I'm no VATs expert but I've read enough on the subject to believe I can speak with some degree of accuracy.

If you try a key and the starter doesn't go, it could be the VATs system isn't reading the key. In the case of the key for our friend, they interrogated the original key and grabbed on out of the bin for that value and cut it without interrogating it and it had the wrong resistor on it.

If it was me, here's what I'd do. First off I'd check the original key and new one with an ohm meter and insure the value on the new one was correct.

If they match, I'd next drop the hush panel and find the wire that carries the resistor value from the ignition switch to the vats system. IIRC on my 86 one wire was orange and there was a connector about 12" from the column you can unhook. I'd put each key in the ignition and read the ohm value on each key off the connector from the column using the ohm meter and confirm they're the same.

I suspect either the keys don't have the same resistor or if they do the resistor isn't in the same relative position on the key. If the keys match but don't check out the same then use a caliper and measure one key vs the other and confirm the distance from the tip of the key and the width of the tabs on the resistor match.

That's the only 2 things I can think of that would cause a new key not to work. Good luck.

1984Z51auto

If you do the above, it will clearly show if there is some kind of contacting issue with the new keys also.

pcolt94

I had this same exact scenario, did not make sense. Had 3 keys made for my new cylinder and I cleaned the hell out of it. I went back to the locksmith and he used a razor blade or such (years ago) and cleaned the contacts and it worked.

He explained the new keys have a special coating that’s difficult to remove with just alcohol. Even though the resistance checked OK, it will not electrically make contact with the 2 contacts in the cylinder.

WVZR-1

That is certainly a possibility but I don't know that there's going to be the "special coating" on the generic blank. I'm surprised that it's even a possibility with a GM/OE blank. It's a less expensive attempt for sure than another key. A scratch with anything or maybe just very light emery cloth, maybe even some 600 - 1000 or greater paper.

sagaz

hi, I have problem bypassing the vat because I lost my only key, so if anybody has the key pelet value of a corvette 1994 I really aprecciate to put the resistance

WVZR-1

It will likely be of no help but take the registration/proof of insurance (either should work) and personal identification to a GM dealer and ask that they do a "KEY REQUEST". Generally I'd think fore a '94 they would only get the mechanical cut BUT there's always the chance that the resistance value/code may come with it.

If the ignition cylinder had never been changed you would have likely the correct mechanical cuts for the car, better than nothing maybe.