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Fun with the immobilizer: I took apart a key and removed the immobilizer chip inside to test the range of the antenna.
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I thought that it would only activate the antenna if the key was correct which is why I didn't just wave the entire key around the ignition. This is wrong, there are separate measuring fields that says if the key is correct for start and another measuring field if the chip is in range and OK.
As it turns out, the immobilizer is only checked at engine start even though it's constantly being monitored. I left the bare metal key in the ignition and engine running and removed the chip - the engine still ran fine for about a minute even though the car knew that the chip signal was gone. I'm assuming that it would continue to run because I'm not going to drive around on public roads with possible risk of the engine shutting down.
Range of a chip in the key is about 1" so if you have a code related to low signal there's no way pushing the key or wiggling it will make the signal stronger. If it does, there was a problem with with the antenna or plug, not the key range. The chip has more than enough range. Outside of the key, a naked chip has about 3" of range.
Holding a VW chip from another car right at the antenna also has no effect. The car knew that a correct chip was in range even though an incorrect chip was also in range. The tested car was a mk5 with immo4 and the incorrect key was a mk4 with immo3, I don't know if this could have made a difference.
In any case, even if you have another compatible immobilizer chip in your pocket, unless you're holding it right up against the ignition slot, it's not going to be read.
More information on the immobilizer: http://www.myturbodiesel.com/1000q_how_to/multi/immobilizer.htm
I thought that it would only activate the antenna if the key was correct which is why I didn't just wave the entire key around the ignition. This is wrong, there are separate measuring fields that says if the key is correct for start and another measuring field if the chip is in range and OK.
As it turns out, the immobilizer is only checked at engine start even though it's constantly being monitored. I left the bare metal key in the ignition and engine running and removed the chip - the engine still ran fine for about a minute even though the car knew that the chip signal was gone. I'm assuming that it would continue to run because I'm not going to drive around on public roads with possible risk of the engine shutting down.
Range of a chip in the key is about 1" so if you have a code related to low signal there's no way pushing the key or wiggling it will make the signal stronger. If it does, there was a problem with with the antenna or plug, not the key range. The chip has more than enough range. Outside of the key, a naked chip has about 3" of range.
Holding a VW chip from another car right at the antenna also has no effect. The car knew that a correct chip was in range even though an incorrect chip was also in range. The tested car was a mk5 with immo4 and the incorrect key was a mk4 with immo3, I don't know if this could have made a difference.
In any case, even if you have another compatible immobilizer chip in your pocket, unless you're holding it right up against the ignition slot, it's not going to be read.
More information on the immobilizer: http://www.myturbodiesel.com/1000q_how_to/multi/immobilizer.htm
