MULTI-FUNCTION INDICATOR FOR
       		     PASSAT, G60, SLC & GLIs
       		 ==================================
       		 Editor: Jan Vandenbrande

From: dilmorecray (Robert J. Dilmore)
Subject: Re: Weird MPG reading on MFA (86 GTI)
Date: 22 Sep 92 12:08:40 GMT
Some edits by Jan

     Ok fellow techo-nerds here it is:
     Multi - function indicator test
     Perform MFI check mode and measuring mode test before doing any repairs

     The following works on Passats, G60s, and probable other cars as well.


     CHECK MODE TEST
     ===============

     Check mode test verifies MFI is operating with the correct base
     vehicle information
      a. set MFI memory switch to position 1
      b. switch ignition ON
      c. press and hold MFI select button
      d. switch ignition OFF, then back ON
      e. release mode select button
         (engine MAP code is displayed)
      f. press and release mode select button to advance to next mode
         (country code should be displayed)
      g. continue pressing and releasing mode select button to advance
         sequentially from mode to mode.

 PASSAT Readouts:
 ----------------

   FUNCTION                   MODE INDICATED        VALUE DISPLAYED
   Engine MAP code            -                     013
   Country code               clock                 1
   speedometer drive ratio    L/100km               920
   Upper RPM limit*           km                    7418
   Lower RPM limit            km/h                  1175
   Deceleration fuel shutoff  oil temp.             **
   Segment test               -                     All segments light up

      *= The displayed numerical value must match the chart, it is NOT an
         indication of the upper and lower overrun fuel cutoff rpm.
     **= The displayed numerical value has no importance for the check. MFI
         is Ok if any value is displayed.


 1990 US G60 with AT Stage I Readouts [jan]:
 -------------------------------------------

   FUNCTION                   MODE INDICATED        VALUE DISPLAYED
   Engine MAP code            -                     026
   Country code               clock                 4
   speedometer drive ratio    mpg                   955
   Upper RPM limit*           miles                 7418
   Lower RPM limit            mph                   1175
   Deceleration fuel shutoff  oil temp.             ** (56)
   Segment test               -                     All segments light up


 1992 US Corrado SLC/VR6 Readouts [jan]:
 ---------------------------------------

   FUNCTION                   MODE INDICATED        VALUE DISPLAYED
   Engine MAP code            -                     039
   Country code               clock                 4
   speedometer drive ratio?   mpg                   6010 ?
   Upper RPM limit*           miles                 7418
   Lower RPM limit            mph                   1175
   Deceleration fuel shutoff  oil temp.             ** (220)
   Segment test               -                     All segments light up
   ?			      ?			    13
   ?			      ?			    0.08



      MEASURING MODE TEST
      ===================

      measuring mode that provides a display of measured fuctions during
      vehicle operation.

      1. Set MFI memory switch to position 2
      2. switch ignition on
      3. press and hold MFI mode select button.
      4. switch ignition off , then back on
      5. release mode select button
         (first function is displayed,see chart)
      6. start engine and drive vehicle
      7. press and release mode select button to advance display

      FUNCTION/DISPLAY                          mode/symbol displayed
      Test sum of programmed bytes *               -
      Intake manifold (mbar)**                     clock
      Engine RPM ***                               km/h
      Momentary fuel consumption                   L/100 km
      Signal from speed sensor ****                km
      Oil  temperture (c)                          oil temperature
      Ambient temperature                          ambient temperature

      *= Displayed value has no importance
     **= The VDO multifunction indicator displays intake manifold vacuum
          as a decimal numeric value instead of in mbar. Chart in manual
    ***= If incorrect go to trouble shooting section (not included:()
   ****= Numeric value should change. (formula for Can. not included)

       NOTES: THIS IS FOR A PASSAT ,
              12 pages of troubleshooting flow charts NOT included
              10 pages of schematics NOT included


 1990 US G60 with AT Stage I Readouts:
 -------------------------------------

      FUNCTION/DISPLAY                          mode/symbol displayed
      Test sum of programmed bytes *               624
      Intake manifold (mbar)**                     Varies: 44-160
      Engine RPM ***                               780 idle, varies
      Momentary fuel consumption                   0.0 & up
      Signal from speed sensor ****                Varies 7547
      Oil  temperture (c)                          Varies
      Ambient temperature                          Varies


 1992 US SLC/VR6 Readouts:
 -------------------------

      FUNCTION/DISPLAY                          mode/symbol displayed
      ?						   7558
      Test sum of programmed bytes *               C10
      Intake manifold (mbar)**                     Varies: 245-750
      Engine RPM ***                               666 idle, varies
      Momentary fuel consumption                   0.0 & up
      Signal from speed sensor ****                Varies 1112
      Oil  temperture (c)                          Varies
      Ambient temperature                          Varies

----
In article <arch.717097885pei> archgandalf.pei (Arch Mott) writes:

>  Boy, I'm glad to see I'm not the only techno-nerd who immediately ran home
>  to tweak his/her MFA! ;^)
>
>  Actually, on my '86 GLi I got 7 different values. If you moved the mode
>  switch (you know, the I/II switch that goes from "last reset mode" to "elapsed
>  since the last time you turned the car mode") the ambient temperature
>  position indicated two different values. I, too, would sure like to know
>  what thes numbers represent. I did notice, though, that they don't appear to
>  change at all when I drive around?

<<re:info given by MFI (or MFA) in diagnostic modes>>

According to my Bently book, the info given in "Check mode test functions"
(MFA switch to position 1, ignition on, press and hold mode select button in,
ignition off, then back on) is as follow (up to August, 1990, pp 91.10-91.11):

Function         Times mode pressed        Mode Indicated       Value displayed
-------------------------------------------------------------------------------
Engine Map code          0                    --                     018
Country code             1                   clock                   4 (USA)
                                                                     1 (Canada)
Speedo drive ratio       2                mpg or L/100km           955 (USA)
                                                                   950 (Canada)
Upper rpm limit          3               miles or km              7418
Lower rpm limit          4               mph or km/h              1175
Decelleration fuel
 shut-off pressure(mbar) 5               oil temp.                  57
Segment test             6                    --               all segments on

For "Measuring mode test functions" (switch on "2", same setup):

Function                             Times mode pressed  Mode/symbol inciated
-----------------------------------------------------------------------------
Test sum of programmed bytes                  0                  --
Intake manifold vauum (mbar)                  1                clock
Engine rpm                                    2                mph or km/h
Momentary fuel consuption                     3                mpg or L/100 km
Signal from speed sensor                      4                miles or km
Oil temperature (degrees F or C)              5                oil temp
Ambient(outside) temp (degrees F or C)        6                air temp


The differences from above for Aug. 1990 thru 1992 model year:

Engine map code--   026 (G60)  or 039 (VR6)
Speedo drive ratio--6160 (USA) or 3800 (Canada)
Check mode test function "5" is "Overrun cut-off vacuum (mbar)"-- 320(G60) or
   220 (VR6)


The 1993 model year and after documentation doesn't seem to list the two
sets of values, but refers to a procedure like the above but using the
odometer reset button instead which then lists the following:

Function Function                  Meaning
number   displayed
------------------------------------------------------------------------------
1        Distance pulse number    3735(All countries except USA and G. Britain
                                  6010--Great Britain and USA
2        Country code             1(All but USA & GB); 2(G.B); 3(U.S.A.)
3        Speedometer/Tach         not required for troubleshooting; used
                                  for production only
4        No. of cylinders         6
5        Segment test             All LCD segments selected
6        Pulse from speedometer   4 pulses counter per 1 wheel revolution
         vehicle speed sensor
7        Engine speed (rpm)
8        Program version          sames as "3" above



<<question about door handle breaking>>


Oddly enough, my driver's side handle broke (internally, not externally) about
2 months ago.  What was really sad was that the service techs were't smart
enough to transfer the old lock cylinder from the broken handle to the replacem
nt.  When I went to pick up the car, they handed me 2 new keys and explained
that they fit the new door handle, so I'd have to use one key to open the
driver's door, then use the original key for the ignition.  After I asked why
they hadn't transferred the old lock cylinder from the broken door handle to
the new one (or set the new cylinder to the same key code as the old one), they
took the car back into the garage and transferred the cylinder.  I refused to
pay for any labor charges for the 2nd go around and since I have an extended
warranty, the whole thing only cost me the $50 deductible.

Mike Stith
Computer Services Division
University of South Carolina
514 Main Street
Columbia, SC  29208
803-777-4409
Bitnet: C0265UNIVSCVM
Internet: C0265univscvm.csd.scarolina

>My MFA does not display all this stuff-- it only displays the mileage, MPG
>and oil temp, I think.  I'm not positive what the third item is that is
>displayed, but I certainly know that there isn't an `engine code' or
>any of those things.  My MFA only displays three items of data, and they
>don't change from register 1 to register 2.
>
>I've got a 93 SLC.  I was always intrigued by all the stuff you other people
>managed to get out of your MFA's.
>
>   Mike (mvoorhiswpi)
>   86 Jetta GL, 93 Corrado SLC, 67 Beetle


And I the same, on all counts.  But then I remembered that I printed out a TSB
at TRAK Auto on the MFA, and lo and behold, here is what is says (Reader's
Digest Condensed Version):

    Group 91, Bulletin No. 94-01, Feb. 15, 1994
    Model: 1993-on Volkswagen Corrado

    Supersedes Bulletin Group 91, No. 93-04 date June 30, 1993

    MULTI-FUNCTION INDICATOR (MFA) TROUBLESHOOTING

    * Calling up MFA Check Mode Test
         1. Set memory switch to 1
         2. Switch ignition on
         3. Press/hold mode select switch
         4. Switch ignition off, then back on
         5. Release mode select switch

    * MFA Check Mode Displays:
         - Momentary Fuel Consumption
         - Oil Temperature
         - Outside Temperature (-40 displayed if temp sensor not
         connected)

[So far, nothing too exciting.  This is what I have seen on my '93 SLC, same
displays whether using memory switch position 1 or 2.]

[--->>> Now the new exciting stuff!! <<<---]

    * Calling up Instrument Cluster Check Mode Test
         1. Switch ignition on
         2. Press trip odometer reset button and hold down.
         3. Switch ignition off, then back on again
         4. Release odometer reset button

    The function and number and data appear on the display window of the
    speedometer.  Press and release odometer reseat button to advance to
    next function.


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    Function  Function Displayed       Data Displayed, for engine code AAA
    Number                                        (2.8 L, VR6)
    --------  ------------------       -----------------------------------

    1      |  Distance pulse number* |   3735    |    6010      |    6010
-----------------------------------------------------------------------------
           |                         |           |              |
    2      |  Country Code*          |    1      |     3        |     4
-----------------------------------------------------------------------------
           |                         |
    3      |  Speedometer/Tachometer | Not required for troubleshooting;
           |                         | used only for production
-----------------------------------------------------------------------------
           |                         |           |              |
    4      |  No. of cylinders*      |    6      |     6        |     6 [duh!]
-----------------------------------------------------------------------------
           |                         |
    5      |  Segment Test           | All segments of display light up
-----------------------------------------------------------------------------
           |                         |
    6      |  Pulse from Speedometer | 4 pulses counted per 1 wheel revolution
           |  Vehicle Speed Sensor  |  and added to counter total.  Display
           |  (VAS)                  | range from 0 to 9999
-----------------------------------------------------------------------------
           |                         |
    7      |  Engine Speed (RPM)     | Engine speed (RPM) is displayed
-----------------------------------------------------------------------------
           |                         |
    8      |  Program Version        | Not required for troubleshooting;
           |                         | used for production only.
-----------------------------------------------------------------------------
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    * If the values displayed od not match those in the table, replace MFA
printed circuit board.

    Country Code:
    1 - All countries (including Canada) except USA and Great Britain
    3 - Great Britain
    4 - USA

    Distance Pulse Number
         If the displayed value does not match the value in the
         table, the distance driven will be recorded incorrectly.
         The distance pulse number is a constant, engine-specific
         value.  The distance pulses for any given driven distance
         can be calculated using the number in the table.

         Example:
         Distance pulse number x distance driven = pulses for driven
           (from table)           (miles or km.)        distance

              6010             x       0.5       =         3005


The TSB then goes on to give lots of good troubleshooting info for the MFA,
including about three pages of flowcharts for troubleshooting the memory and
mode switches alone!  Unfortunately, most of the fixes amount to replacing the
printed circuit board. :-(

As I believe someone else suggested earlier, if the MFA shows odd behavior,
e.g., unrealistic displays, no displays, etc. it can be reset by
disconnecting the battery ground strap and then reconnecting it (WARNING: be
sure to have radio code!!).  This is also suggested for "synchronizing" the
"digital clock counter" on VDO instrument clusters if clock deviates more than
5 seconds / 24 hours.

Other implied accuracy specs.:
    Driving distance display - deviations up to max. +/- 4% are permissible.


As for MPG, the text refers to a "fuel consumption signal" from the Engine
Control Module (ECM).  I wonder if this is a different signal than the engine
vacuum  (a calculated flow based on fuel injector pulse frequency, which is
determined by ECM?), since there is no engine vacuum readout in the test
modes.  This may explain why some folks have said their MPG is not too
accurate while others (including me) say theirs is quite accurate.

Another interesting tidbit:  says outside air temperature sensor is located on
right side behind front bumper.

Well, I haven't tried this on my '93 SLC yet, but I'm sure going to - after
all this typing I need some fun!

    - Lenny Cavalier
    cavalieroasys.dt.navy.mil
    '93 Corrado SLC VR6 \/\/\/

After the discussions the other day on the list, I just had to check out 
these test modes to see if there was anything there.

  I found the digital tach in function 7 of the odometer test mode.  It  
would be cool, but it has a fair amount of lag.  It could still be used 
to calculate actual speed vs. indicated, though.

  In the MFA test modes, there is a current MPG mode instead of avg., 
but there is some SERIOUS lag on it, like maybe a full second.  It is 
still educational, though.  All of you guys out there complaining of 
fuel mileage problems could use it to see if it's just your driving 
style.  I avereage about 17-18 in town, which I know is my fault, and 
about 28-29 on the highway.  This is with a TT chip.

-Dave
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    list archive, etc.  see:   

I have '95 GTI, which is OBDI, so yours may be different.  Anyways...

To access the odometer test modes, turn the key to the on position(where 
all the idiot lights light up) and press and hold the trip meter reset 
button.  Then turn the key off then back on and release the button.

The MFA test modes work the same way.  You need to have it switched to 
position 1, then go through the above procedure using the MFA mode 
selector button.

Oh, one other thing...  the current mpg function never goes to zero.  It 
always registers .2-.6, even sitting stopped with the engine running.  
Must just be a glitch or something...

If you really want to know what all the different modes are, there is 
some stuff about it in the archives.

-Dave

On Thu, 19 Feb 1998, Hoang Nguyen wrote:

> How do you access the test modes? I have a '97 GTI...
> 
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    list archive, etc.  see:   

The odometer trick worked on my 96. I don't remember if it was the exact
same procedure, but I know it was possible.

Now, a cool trick on the 2000s is to dial in you "secret number" on the
odometer using the clock knob and odometer reset button so you can start 
the car with a mechanically correct but electronically unmatched key.
Sounds goofy at first, but I've already broken one key (which had the
potential for damaging the immobiliser piece, plus another situation that
required using an unmatched key. I'd advise any 2000 owners to learn your
secret number like you learn your bank card PIN, and learn the procedure
for entering the number. See 
Hell, print the pdf and stick in the glove box for when you need it.
Get you secret number from your key tag or ask your selling dealer. If
both strike out, a dealer has to use a 1551 to pull an ID number from your
system to get the code.

Believe me, if you call a dealership when you need this emergency
procedure, they probably couldn't tell you. 

Josh

Philippe Tirman <sntacruzpeepearthlink> wrote:
>I tried this on my OBDII 96 and it didn't work. Someone posted this a
>long time ago on the vortex along with a description about what each
>things did. Does it always give you exact rpms or does it stop once you
>turn you car off?

All in the archives.. of course.
Check out the table here:
http://www.gti-vr6.net/library/electrical/MFA_tricks.html#mark4

Ok, to make that work on a later model GTI
use the regular trip odometer reset button under the speedo as follows.
Put the MFA into position 2.  Start the car, now hold the
tripmeter reset button down, while simultaniously turning the
car off and back on (actually just ignition on, off, on will do
it without starting the car).

In my 1995 GTI VR6, I have to actually start the engine (not just turn the ignition on), hold the tripmeter button down, turn the ignition off (which shuts off the engine), then turn the ignition back on, optionally starting the car.

It should show the number 1 briefly and then switch to the value 6098.
As you press the trip reset button it'll show 2, 3, 4, 5 ... 8
If you let it sit for a second the mode number will be replaced by some
other value.  The values match what's listed in the table shown
at the link above.  Mode 7 is the rpm counter.  It's delayed enough
to be worthless for anything but trying to hold your speed steady.


The other trick is this.
Again set the MFA to position 2.
Now hold the MFA selector button down,

That's the button on the end of the MFA stalk. aqn.

and simultaniously turn the
ignition on, off, and back on.    The MFA will go into a simple
mode (older cars had more neat shit), where the first position
will show instantaneous miles per gallon.

It may be based on intake vacuum partially but it is smart enough
to know when the engine management system has cut fuel flow
completely, which the old style MPG meters would never do.
Maybe it just counts squirts of gas through the injectors.
(Can someone with a turbo try this one, and see what it reads when
you're under boost?)

Anyway, what's interesting to see is that any time you let off
the throttle it cuts fuel flow completely.  This means it takes
less gas to coast in gear, than it does with the clutch out
or out of gear.   Any time it's idling it burns fuel.  Any time
it's coasting it does not.

Let the car warm up (get's horrible mileage when it's cold) and
drive it around for a while in this mode and see what it takes to
maximize MPG.   The MFA is still calculating when when it's in this
state, so you can reset position 1 or 2 just prior to starting in the 
diagnostic mode, drive around for a while, and see if your efforts
were rewarded by a good average MPG number.

I did an 11 mile loop with about 4 stop signs, 3 stop lights and
one drag race, and got 26mpg.   If the price of gas ever gets too
high you could drive around like this all the time.  ;)

BTW, I tested the cruise control because of something someone said
the other day about getting worse MPG with cruise on.
In my car it did very well at maximizing MPG with no cycling
at all.  It didn't cycle on/off or over modulate the throttle.
The instantaneous MPG display is very sensitive to small throttle
variations, and it would have shown it.  


    ian