re: failed car ignition

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Black Moon by way of Terry Fritz <teslalist-at-qwest-dot-net>" <black_moons-at-hotmail-dot-com>

60 to 100khz? gez, everyone and there grandmas smps uses that freqency!
And if they don't, they probley use one lower that has a harmonic of that 
freqency (Smps = squarewave = tons of noise all over)
CRT monitors operate around that freqency with a sawtooth wave, (horzontal 
scan) so they can probley cross over and interfer.. Lots of stuff is 
probley pertty close to that freqency, what a horrable freqency to pick


>This is quite interesting.. The RF link from engine control unit (ECU) to 
>transponder in the ignition key is a low frequency inductive link (60-100 
>kHz or so..).. The coupling is usually done by a coil that surrounds the 
>ignition key lock.  All the smarts is in the ECU (so you can't defeat it 
>by cutting some wire in the steering column).
>
>It is not out of the question that a TC might radiate enough energy to 
>couple into this system and confuse it enough that the ECU and key can't 
>run their protocol.
>
>
>At 07:40 AM 7/8/2003 -0600, you wrote:
>>Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
>><IanHelixsp-at-aol-dot-com>
>>
>>Hi all
>>
>>My previous occupation was as a technician, working for Audi/VW (18yrs).
>>During the last few years we had more and more complaints about vehicles 
>>refusing
>>to start when parked in certain locations! After some time and processes of
>>elimination I realised that this was due to r.f. interference from radio
>>transmitters i.e. near the local police h.q. etc. (Also in the same 
>>areas, cases of
>>continuous false alarms from vehicle security systems) I have never had an
>>instance of a vehicle breaking down due to this, just failing to start. I
>>attributed this to the vehicle immobiliser system, which usually takes 
>>the form of a
>>radio transponder within the ignition key. The E.C.U. is programmed in a 
>>'fail
>>safe' mode to prevent the vehicle from breaking down once started and 
>>running.
>>In other words the immobiliser's digital out-put is ignored once the engine
>>is running.
>>
>>Cheers,
>>Ian D. Liverpool U.K.
>