http://www.tobio.info/passat/howtos/climatronic.txt
Or incase Link goes belly up
The speedometer has a factory built-in error to show a speed faster than your actual speed. The Climatronic (automatic climate control) system includes a number of sensors that you can access through the diagnostic mode. To see your true speed in digital format press the following key combinations:
1. Press Fan Down, Temperature Colder, ECON at the same time.
2. Use the temperature control buttons to cycle through the various channels to Channel 16.
3. Press ECON to go back to normal. (It goes back automatically when you restart the car.)
1 system error
2 actual value virtual sensor
3 actual value of interior console sensor
4 actual value outside temperature sensor at water reservoir
5 actual value outside temperature sensor at bumper
6 actual value blowing out footwell sensor
7 actual value blowing out dashboard sensor
8 display checks
9 actual digital value acknowledging potentiometer temperature flap
10 target digital value temperature flap
11 actual digital value acknowledging potentiometer A/C flap
12 target digital value A/C flap
13 actual digital value acknowledging potentiometer Fuss/Def. Flap
14 target digital value Fuss/Def. Flap
15 actual digital value acknowledging potentiometer ram air flap
16 target digital value ram air flap
17 driving speed (km/h) = Channel 16
18 actual value of the blower voltage (volt)
19 desired value of the blower voltage (volt)
20 actual value of the compressor/on-board voltage (volt)
21 amount of of low-voltage events (not volatile)
22 switching status of the high pressure sensor
23 number of high pressure events (volatile)
24 number of high pressure events (not volatile)
25 A/D value kickdown switch
26 A/D value hot light
27 engine speed
28 compressor number of revolutions
29 coding
30 software-Version
31 software index
32 potentiometer error counters of temperature flap
33 potentiometer error counters of A/C flap
34 potentiometer error counters of Fuss/def. Flap
35 potentiometer error counters of ram air flap
36 temperature flap notice coldly
37 temperature flap notice warmly
38 A/C flap notice closed
39 A/C flap notice openly
40 Fuss/Def. Notice Def folds.
41 Fuss/Def. Notice foot
42 ram air flap notice on
43 ram air flap notice folds to
44 operating cycle counters
45 interior temperature counted (Nine) dig
46 outside temperature filtered °C
47 outside temperature not filtered °C
48 ECOR of
49 error counters Tachosignal
50 service life in min
51 engine temperature °C
52 compressor switching off conditions (appendix)
53 announcement more actively el. Exits x x compressor circulating air valve x water valve
54 rule index
55 outside temperature °C
56 interior sensors virtual °C
57 interior sensors console °C
58 temperature water reservoir °C
59 temperature bumper °C
60 blowing out floor space sensors °C
61 blowing out Dashboard sensorts°C
62 sun intensity W/m² = Channel 3
63 sun intensity filtered W/m²
64 delta exhaust rise
65 delta A/C flap shift
66 time constant 1.8 seconds of
67 cold weather starting correction
68 maximum correcting of variable for i and/or p-portion
69 actual value blowing out sensor foot (cnts)
70 desired value blowing out sensor foot (cnts)
71 deviation (Epsilon) 72 portion (cool +heizen)
