Sorry, I didn't read the test you run with the power supply. I guess there's no real need to fire up the engine since you already figured the plugs work.

One thing I'd check is continuity across the glow plug wire and inspect that there's no signs of corrosion on the control module's pins...

Would be nice to have my intake cleaned in a ultrasonic cleaner and been trying to find any place around my area but most of them have small size cleaners.Does anybody know any ultrasonic cleaning facility in Vancouver,Canada?
Google didn't help me on that:)

UPDATE:

So it was the faulty glow plug controller which dealer replaced under CPO.But they suggested and offered to replace all 6 glow plugs for just ~$700 :yikes::yikes: and i refused it.So far driven around 300kms and no check engine sign.Hopefully new controller will last longer after new thermostat.:)

The controller is less than $130, I just ordered it to replace mine

Its funny, it seems that its the same people who have the same types of problems. Is it just that we have kept our X5s the longest and now are running into what will become typical issues?

Don't know if there is a pattern but I had the plugs and controller done. BMW took most of the cost. I also recently swapped the thermostat and prior to the glow plugs several components in the DEF system were replaced. Now it seems the third active tank needs to be replaced again....I believe most if not all of the 35d all go through more or less exactly the same failure modes.

Are you still under some sort of warranty, or did BMW do this via an emissions warranty?

The Service mgr got them to help. No warranty left.

Yes that's funny.First mine urea injection valve went then yours and now mine controller and now it was your turn.Good thing is that glow plug controller is not super expensive.

Well, looks like it is my turn to deal with this issue. Started popping up a few days ago when my GF was driving the car. Error has been on and off over the past few days - may look at replacing controller, glow plugs, and swirl flap delete while I am at it. 2011 X5 is at 99k miles

https://dl.dropboxusercontent.com/u/...low%20Plug.PNG