VSS Signal on 01E

I would like to find information for the output signal for the VSS (vehicle speed sensor) on the 01E transaxle. Voltage, waveform, and PPM (pulses per mile/kilometer/revolution). I suspect it's the same for all late model VW/Audi 01E and 012 transaxles. Any help would be greatly appreciated.

Andy

Andy

I have a 01E sitting on the floor at work.
I did notice the speed senser has 3 terminals to me that would indicate a hall effect senser.
Voltage ground and signal.
Signal is often the centre but dont take my word on that(wiring diagram).

If you pull the senser out you should be able to see the chopper wheel and count the segments or teeth.
That will give you the amount of signals per rev.

I hope this gets you closer.

Jim

Andy\Jim,

I've got an O1E in my gt40 and I have never been able to get a signal from the hall effect sender in the gearbox. I asked a service technician at the local Audi dealership and he thought there was something in the dash in Audis which helps pull the signal up.

I ended up fitting an aftermarket external sender unit to provide the speed signal tiggered from the driveshaft flange bolts.

I would also be interested to learn what required to get a signal from the sender on the gearbox, anyone have any ideas?

Andrew

Perhaps there's a Porsche or VW tech on the board? The 5 speed Boxster used a model 012 gearbox which I suspect has the same VSS as well.

Here's a discussion regarding a GM VSS. Need to find something similar for the Audi/VW.
http://www.jagsthatrun.com/V8-chapters/V8-tpi-Speed-Sensors.pdf

Andy

I was able to gather some more information, though there might be some doubt cast upon it. Since it is a three wire sensor, I was told it is a Hall Effect sensor producing a sine wave at 5 to 8 volts peak to peak. Pins are +12V, ground, and signal. Driven by the differential output shaft sensor gear, it produces one of the following: 8, 16, or 32 pulses per revolution (of the output shaft or transaxle drive flange). I spoke with North Hollywood Speedometer, and they asked to put the car on their calibration rollers and they'll read the signal; which is another way of saying they don't know for sure (that's not a hit on NH Speedo; they're indeed very fine and reputable people to deal with). Also, they told me the Porsche electronic speedo will read any signal; I don't know exactly what that means, but I suspect that statement was aimed at mainly the German stuff. An inquirey to the Audi Forums produced little other than hook up and oscilloscope to it.

Cheers,
Andy

Guys,

If you can't get the precise number for your VSS, there is another approach which should get you to a good speedo reading in a very few trials. Its called a binary search. Most speedos allow for a wide range of ppm by setting dip switches, which, in essence, set a binary number with 0=off and 1=on, usually The easy way for us base 10 oriented people to work with this is to use the scientific calculator that comes with Windows to translate between decimal and binary numbers.

Note the number of switches that are used to set the speedo. Lets say its 12
Set the calculator to Bin and enter twelve 1s into it. Then set the calc to Dec.
The number turns to the number 4095. Divide by 2 (2047.5).
Then click Bin again and you see that 2047 = 011111111111 Bin
This is your starting point, so set your switches like this.
Check your speed and consult your speedo docs for adjusting slower or faster.
Lets say you need to go up numerically with your switch. Set Calc to Dec
((4095-2047)/2)+2047 = 3071 Do this on calc then set to Bin, and you get 101111111111
Set your switches like this and try again.
Set switches again, going ½ way to previous or next mid point (depending on the direction you need to go)
Repeat until you get an accurate reading. You'll be amazed at how fast you get there.

This is for an Audi tt but I suspect it will be no different. pin 1 blk/wht-12v, pin 2 wht/blu-signal, pin 3 brn-ground. If you dont have the pigtail, take a guess as to which is 1 and which is 3, sensor will be fine. I suspect if you are looking at the sensor connector with the locking tab pointing up, #1 will be on the left.
Testing-pin 1 to 12v, pin 2 to dvom + pin 3 to ground, dvom - to ground. Slowly turn the sensor, watch for high and low voltages. It should be square wave, not sign. You will see the switching points. Count the number of highs, that is your pulses per revolution. If you want pulses per mile, calculate your final drive and the speedo drive, figure out how many times in a mile it will pulse and there you go.
It looks like automatics might use vr sensors so if that doesnt work, connect a dvom to pin 2 and 3 on a lower voltage setting and spin the sensor as fast as you can, see if you get a reading.