The "electronic throttle modules", actually pedal position sensors, are
rarely, if ever, a simple rheostat.  The Bosch variety uses two Hall
effect sensors mounted 180 degrees to each other.  These are in turn
subjected to a field that rotates as the shaft is rotated.  This way a
signal and anti-signal is produced.  Only if they match correctly does
the ECU operate on the signal.  A simple rheostat would kill a lot of
folks.

...Alan

-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf
Of Tom Page
Sent: Thursday, June 28, 2007 3:55 PM
To: Microcontroller discussion list - Public.
Subject: Re: [EE] How far do you go? - was:
[EE]Firmwareflawsandfacelesscorporations

It is quite simple to test the resistance across the 
terminals of the sensor


On Thu, 28 Jun 2007 17:57:51 -0400
  Walter Banks <walter@bytecraft.com> wrote:
> 
> Herbert Graf wrote:
> 
>> On Thu, 2007-06-28 at 14:58 +0100, Alan B. Pearce wrote:
>> > >I believe the Vovlos suffered from failure of the 
>>electronic
>> > >throttle module rather than the ECU.  This is part of 
>>the
>> > >"drive by wire" system which I have always considered 
>>a very
>> > >poor idea.  Give me a throttle cable any day of the 
>>week.

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