So here's the latest... I pulled the connections to the ECM, to check for continuity in the harness'...about half of them set off the meter the others got no reading. Don't know what's up with that, would think they should all give a reading. Double checked the crank sensor, it gave a reading of .318 ohms. Just so happened to have a new one...the reading on that is .314ohms. So the problem is either in the wiring or the computer...I'm thinking it's gotta be the ECM. Is there any way of bench testing? Oh yeah, I was able to access a wiring diagram from volvotechinfo.com...$3 for three days. Makes no sense to me as I am not familiar with electrical schematics. Printed off what I thought to be relevant...

 

There's no reason to expect any kind of similarity in the many connections to the ECM. There are a lot of circuits doing very different jobs in that bundle. What you need to work out is the amount of resistance from the line going to the crank sensor line to ground (the battery negative terminal aka the engine block). If you're just reading the same resistance as that (good) sensor, then you know that's not where your problem is.

Think of it like a water leak, where the "water pressure" is your voltage, and the current drain blowing the fuse is a "water leak". You need to find the "leak", which will correspond to the low resistance to ground on one of the circuits powered by that blowing fuse. Read my previous post and see if you can work out that process... it'll save you hours of time and a LOT of money and frustration.

 

Ok, so I hate to admit it...but after weeks of searching for this electrical problem and coming up empty handed, I pulled the car to local mechanic who specializes in the European cars. Turns out it was the crankcase breather valve, aka the PTC valve. Located on the air intake tube right before the turbo. Cost me $164.48, my only regret is that I didn't do it sooner. Now to find a PTC without having to buy the air intake tube. Can't believe they don't sell that separately. Thanks for all your help!!