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Discussion Starter #1
Hi.

Recently, every few starts, my engine starts and immediately stops, and a yellow key light appears on the instrument panel.

I tried to change keys and the battery (of the remote control/key), but it didn't help.

What can be the problem?

Also, I have an aftermarket 'code' device that I need to enter before being able to start (an insurance demand...). I am wondering if maybe it has a problem that causes this. (But, when I enter a wrong code it doesn't act as my problem but just doesn't start at all).

Thanks.
 

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Hmmm... my best guess is that it's a problem with your instrument cluster and/or wiring. Those are the parts responsible for the operation of the IMMO system. (Although I think the antenna is near the ignition switch; I suppose that could be bad too...) Either that or there is a problem with your key. (FYI, the part of the key responsible doesn't run off the battery.) Have you tried a different key for a couple weeks to see if that helps?
 

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What sirwired said. Normal operation when the immobilizer chip in the key isn't detected. Now the question is WHY? What changed since it worked properly?
 

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Check your fuses also. I think there may be a 5 or 10 amp fuse that has something to do with the immobiliser.
 

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The engine starting then immediately shutting off and the little "key" light on the dash going on indicates the immobilizer is shutting the engine off. If the immobilizer system doesn't "see" the chip in the key, this is how it's supposed to behave in order to keep your car from being stolen.

Could be the chip in the key you are using.
Could be the little sensor in the steering column that senses the chip.
Could be something involving your aftermarket code device and the way it is wired into the car.
 

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Discussion Starter #7
Thank you for the comments.

1. I tried to use both keys, and it happens in both of them.
2. Can it be a fuse even if it happens only every 5-10 starts?

Thanks.
 

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I'm pretty sure we've narrowed it down to the anti-theft system of the car. If both keys behave the same way then it's probably something inside the car thats the problem. There is a small "antenna" ring mounted around the ignition switch and it has a harness plug with very tiny wires plugged into it. There are still many things that could go wrong, such as; plug coming loose, wires broken, antenna ring out of place, or the control module is faulty.

On a side note, I had experienced a simular problem with some Fords (one of the first auto manufactures to use transponders in keys) that when the key was left in the car and it was extremly cold the transponder chip would give a false code. Warming up the key usually solved that problem. But if you're keeping you key in a warm place (like most people do) it probably isn't what's going on here.
 

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Discussion Starter #9
When the anti-theft system operates (ie when the wrong or no code is entered), it just doesn't let the engine start at all. That is, the phenomenon is different. Is it still reasonable to believe that this is the problem?
 

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I disagree. USA spec cars, at least, are designed to let the car start and run for a brief period before shutting down. The OP is showing textbook behaviour for the immobilizer being triggered - correctly or incorrectly. I'm thinking his aftermarket code device; certainly enough people have had trouble with adding remote start or alarm systems.
 

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When the anti-theft system operates (ie when the wrong or no code is entered), it just doesn't let the engine start at all. That is, the phenomenon is different. Is it still reasonable to believe that this is the problem?
Your code-requiring aftermarket device may not let the engine start at all, bit the stock IMMO (which triggers the "key" light) will let it run for a few seconds before killing the engine.
 
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