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VATS Problem!


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Hello Everyone!

I am having a intermittent problem with the VATS on my 93 ETC. The ETC will work for several days then not! I have found that after many 3 minute attemps with the remote start and 4 different keys that by leaving the car for about 30-45 minutes the ETC will start. When i try starting my ETC it would display in the DIC "car won't start due to theft system" message. It then proceeded to tell me to "wait 3 minutes" and then start the car. So I waited for the 3 minute timer to tell me it was OK to start the car. At this time i'd try to start the car it wouldn't start with the key it would act like it was a dead battery. Today i just keep trying for about 90 minutes and had no luck. I even tried to use the remote starter function and it would try for several times to start till i canceled the remote starter function. I have noticed that while the VATS is cooperating (car will start) the Security light is on sometimes while driving but not always. I stopped at the Caddy Dealer today and was told there are 2 possible modules to replace. The cost is 160 dollars and 350 dollars. This was for the modules and not the ignition switch. I am going to try and follow the shop manual tonight or tomorrow. Has any one else had this problem? I did a couple of searches in the archives but didn`t find the answer! Any suggestions!



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I had intermittent problems like that once, and I cured it by changing the battery cable.

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It may be possible that the wires on the ignition lock cylinder fractured and as a result, the ECM is not seeing the key pellet - no matter what key you're using.

You can easily test the PASS key wires with a digital ohm-meter. Measure the resistance of the key pellet. Remove the hush panel under the dash and unplug the harness connectot that has two small white wires inside an orange jacket. It looks like modular phone wire. With the key in the ignition, measure the resistance between the pins on the ignition side of the PASS key harness - if it is close to the key pellet resistance, the lock cylinder wires are OK. If the resistance is infinite, the wires are broken at the ignition lock.

Access to the lock cylinder is gained by removing the airbag, steering wheel and lock ring. It is not that bad of a job but you do need some special tools - they are easy to fabricate. I did the job on my '93 Fleetwood a couple of years ago - It wouldn't crank and the PASS KEY FAULT light was displayed - once I removed the components to access the lock cylinder, I could see the broken wire. A new lock cylinder fixed the problem - I had it re-keyed to my existing ignition keys for $10 at a locksmith that my local dealer uses. I also made a "Cheater Cord" with the old lock cylinder wires and a resistor so if it ever acts up again, it won't strand me anywhere. :lol:

'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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It`s been 2 days now and what i am doing is leving the can running for my quick stops and just locking the doors! The ETC is working just fine! I am hoping to get some dianogitic time this Saturday! But if it is working i am not sure how i will find the problem! I am considering the passkey module! Since i have a remote start system and the key is not needed. When the car acts up niether method of starting will work. I have cleaned the key reader in the ignition switch and uplugged the connector at the Pass Key module and reconnected them. So i guess Saturday will be starting the car every 10-15 minutes till it fails then we can check the reading at the base of the steering column and at the PassKey module. Plus i have noticed while driving that the security light is staying on sometimes for the entire ignition cycle (running till i shut off the car) but still is starting!



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Well here`s the latest findings! The VATS has allready had a Override kit installed with a relay for the Remote Start! So that eliminates the pellet in the key and the ignition switch! I am now just wondering about the relay that was part of the Override kit! That could be my intermittent problem? My readings at the Pass Key module were within 2 ohms of the all the keys values! So i am down to 2 choices now! 1. The Pass Key Module needs replaced! 2. The Remote Start has issues affecting the VATS! Possibly a weak connection? When i spoke to the Remote Starter installer on Friday...he was more than willing for me to bring the car in to be looked and said they could fix it! So this must be a common issue! Will call on Monday! I am thinking they will just replace the VATS override relay as a trouble shooting starting point.



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I was surfing the net and came across this solution for relearnig the Pass Key Module! You turn on the ignition and wait for the Security light to go out and then turn the key off. You must repeat this 3 times for the module to learn the pellets value! Any one heard of this?

Here is the link!



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I found the below info on ebay:


Vats stands for Vehicle Anti Theft System. Lots of people refer to this type of key, as a " computer Chip key". This key or "Chip" has nothing to do with a computer, nor is it a chip. But because of the popularity of calling it a computer chip key, so will we. So that we don’t confuse. The black chip on the blade of the key is actually a resister. GM first started using the Vats key in 1986 on the Corvettes, then some of the Cadillac’s, ect. GM uses 15 different resistors in their vats keys. Just looking at the keys you can’t tell the difference.

How does the Vats System work?

Each vats key has it’s own unique cuts on the key to operate the lock. But the cuts alone will not allow the car to crank. This is called a mechanical key. Each car has a Vats module (Brain) under the dash that communicates to the starter, fuel pump, and the ignition lock. Each vats module is randomly given a # (value) from the manufacturer. When the proper mechanical keys, with the proper vats chip (resistor value) turns the ignition lock, the vats module reads the chip on the key. If it is the correct chip, the vats module will tell the starter and the fuel pump to operate. If the wrong chip is read, the vats module will tell starter and the fuel pump to shut down.

How to determine the Value of your key?

By chance you may know what vats key you now have. Most people do not. There are basically two ways to determine what vats key you have. Remember, there are 15 different possibilities. First, your key can be " read " in a vats tester. Most locksmiths have these readers, and don’t charge anything to tell you. There is a way for you to read the key value yourself. If you have a Volt Meter you can test the OHMS (The Value) of the chip yourself. Just set your Voltmeter to check to 20 K OHMS Take each lead and place it on each side of the " chip " on your key. A number will appear. Take that number on your voltmeter and apply it to the OHMS chart below. Keep in mind that it may not be exact. Just pick the closest value to your reading. I do realize that some of you don’t even know what a Volt Meter is, not to mention having one. So there is a great alternative for you. Just take your key to a Radio Shack, or your local Auto Mechanic. Ask them to do as I described above.



1———— 0.402

2———— 0.523

3———— 0.681













I will need two things after you purchase. First the year of the automobile and second The Vats number you need based on previous chart.

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