Its still the crank sensor Arif, let me break down exactly how the crank sensor works.
You said you had no spark correct? Whats gonna cause all the spark plugs not to fire?
You replaced the ICM or power output stage, this just steps up/controls the voltage, it doesn't stop the plugs from firing, so that was a faulty diagnosis.
The ECM controlls spark, but the ECM hardly ever fails, so whats the input for the ECM to instruct the ECM to fire the spark plugs? The crank sensor of course. The crank sensor reads the knotches off the flywheel/flexplate to know exacty where the pistons are at and give the ECM the imput for the ECM to give out an output to the ICM.
So what im saying is the only two things that are gonna cause your problem is either the crank sensor or ECM, since the control modules like the ECM hardly fail the crank sensor is the most likely cause.
Yes, as 99A4NOW said you could check the sensor signal and it would be a square wave form on an ocsilliscope.

 

I just replaced the part. It's not hard to do but dirty work.

It runs fine for now.

 

aRif... I have a 98 a4 2.8 and am having the exact same problem as you right now... i'd like to talk to you about it... and maybe be informed as to if the crank sensor works or not for you..

 

Old Sensor vs. New Sensor

 

Good deal, it shouldn't bother you anymore.

 

Hi, all: My 2007 A4 3.2 had a crank no start issue that was intermittent and unpredictable. It never caused a check engine light. I changed the fuel pump and fuel filter, and it was fine for a while, then the problem came back. I'm glad I just bit the bullet and it took it to my mechanic. With his professional scan tool he saw the car needed a new EFI relay and a new ECM relay. I just got it out of the shop today, so hopefully that is my definitive solution, and not just another band-aid.

SOLUTION: MY EFI AND ECM RELAYS WERE BAD.