ABY versus 3B Ecu pinout

[S2central.net]

SO the updated pinout spreadsheet I have now looks like this... It should now align 100% with TommyRS unless someone spots any other clangers.

I need to update my website with this info now.


Paul

[S2central.net]

I know with 100% certainty that the Bentley was/is wrong. I wasn't the first to discover this. What cinched it for me was some X-rays of the POSs I found that showed the traces to the imbedded chip. With that info, it was easy to see how the Bentley was wrong about the N127 pin-out. I documented this back in Sept. 2005:

http://forums.audiworld.com/s4s6/msgs/83085.phtml

Paul: I will try to find the document with the X-ray views and link you to it.

OK - I think we have root caused it then... The confusion with pins 1 & 3 transposed on the 4-pin input side makes sense with reference to your notes about internal connectivity you saw on that X-ray as the sense of I1-I2-I3 then aligns with E1-E2-E3 where we can agree what POS channel lines up to what cylinder. Jees...

Looks like the old AAN training handbook was right and I had put too much trust in the Erwin schematics - especially has three variations of them all agreed - and are all wrong.

[Jonas_R]

Where do one get the VSS signal from?

Also as I read it I dont need any new sensor according to the schematics?

[S2central.net]

VSS comes from speedometer - its a blue/white pin that goes to places like the rear diff controller, the ambient temp display amongst other things...

[S2central.net]

The source is pin 18 from the BLUE connector at rear of instriment cluster... not much room there to splice in a new connection - follow the wire on your 3B to the wiring panel at drivers footwell and you should have more room. If you have ambient display then there is good space for a new splice on that wire.

[Jonas_R]

Oki already have that for my CC so that should be no problem

[UrS4boy]

OK - I think we have root caused it then... The confusion with pins 1 & 3 transposed on the 4-pin input side makes sense with reference to your notes about internal connectivity you saw on that X-ray as the sense of I1-I2-I3 then aligns with E1-E2-E3 where we can agree what POS channel lines up to what cylinder. Jees...

Looks like the old AAN training handbook was right and I had put too much trust in the Erwin schematics - especially has three variations of them all agreed - and are all wrong.

Paul: I sent you a mac dot com email with a jpg of the x-ray of the POS. Shows everything.

Dave F.

[S2central.net]

Thanks Dave - good stuff...

[UrS4boy]

Paul: I sent you a mac dot com email with a jpg of the x-ray of the POS. Shows everything. Dave F.

Here is the view for all to see:



Note how the third pin from the top on the right side (4 pin side) is the ground for all three internal chips. You can also see how the power flows from the four pin side pins through the respective chips (transistor/switches) through to the three pin side and then on to the OE coils.

[Tommy200rs]

Reason for errors is in Factory manuals:
Pin number error is the factory self study training manual(s):

http://www.20v-urquattro.de/new_page_98.htm

end stage 1 and 2 numbering corrected (black and red text) here to picture where the error was

http://www.20v-urquattro.de/new_page_100.htm

Easiest road speed signal source is under the back seat where the rear dif steering box wire connector is. Rear dif lock steering is speed dependant and therefore the speed signal is there also available.

[UrS4boy]

Reason for errors is in Factory manuals:
Pin number error is the factory self study training manual(s):

http://www.20v-urquattro.de/new_page_98.htm

end stage 1 and 2 numbering corrected (black and red text) here to picture where the error was
http://www.20v-urquattro.de/new_page_100.htm

Based on those factory diagrams, their error was showing the ground pin at the outside end rather than one in from the end, as shown in the X-ray.