code dump - code 2111 speed sensor + RPM & Hall interoperation

[Bernard Littau]

I hypothesize the ECU throws 2111 in at least two cases:

If the ECU sees a TDC signal before (or after) the expected number of teeth
go by the RPM sensor, it throws code 2111.  The car will still run with the
bad signals, as the timing will likely be close enough.

Or, if the ECU sees Flywheel Hall and Distributor signals, but no RPM
signal, it can throw code 2111.

The second one is very likely to occur while cranking on a no start
situation, then pulling codes.  If the code occurs on a running engine, then
I would suspect the first.

I'm educated guessing here.  I haven't dealt with the 2111 on my car.

As I think about it, both cases are really the same, just in the second one,
the received count would be zero rather than close to the 135 teeth number.
So maybe the ECU throws the 2111 code in only one case, when the count of
teeth signals between two TDC signals is not 135, throw code.

Best,

Bernard Littau
Woodinville, WA
'88 5ktq

> -----Original Message-----
> From: quattro-admin at audifans.com [mailto:quattro-admin at audifans.com]On
> Behalf Of Richard J Lebens
> Sent: Wednesday, September 18, 2002 5:43 PM
> To: quattro at audifans.com
> Subject: Re: code dump - code 2111 speed sensor + RPM & Hall
> interoperation
>
>
> I could see it working like this but then how does it run with no RPM
> signal?  Like with code 2111
>
> --- Orin Eman <orin at drizzle.com> wrote:
> > It's like this:
> >
> > Timing sensor senses a single pin at 62 deg BTDC on cylinder 1.
> >
> > RPM sensor senses flywheel teeth.
> >
> > The Hall sensor defines a window in which the timing sensor signal
> > should occur - on the compression stroke for cyl 1.
> >
> > Ignition timing is done by counting flywheel teeth using the 'RPM'
> > sensor, starting at the timing sensor signal for the compression
> > stroke
> > on cyl 1.
> >
> > Broken flywheel teeth or a defective RPM sensor can screw up your
> > ignition
> > timing if the sensor doesn't 'see' all the flywheel teeth.
> >
> > For more resolution, the ECU uses both edges of the RPM sensor
> > signal,
> > giving resolution of 1.33 degrees.
> >
> > Orin.
> >
> > > I'm confused.
> > >
> > > Reference sender tells ECU TDC cyl #1 intake/exhaust or comp/power
> > > stroke.
> > >
> >
> > > > Subject: 2111 code on 97 5ktq
> > > >
> > > > Hello listers.......a question about code readings.
> > > >
> > > > 2111 indicates "RPM sensor signal not getting to Mac 11C ECU in
> > my 87
>  message truncated ===
>
>
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