Ford Escape / Hybrid :: 2004 - P0403 Code Came Up For EGR Solenoid

P0403 code that came up on our 2004 Escape 3.0.

Weekend before last I dropped the oil pan, cleaned it and the pickup screen out, and replaced the gasket (switching to full synthetic has been a double edged sword with the leaks that are popping up...); put in new plugs new upper intake manifold gasket and cleaned the throttle body and manifold out. All vacuum hoses inline with the EGR solenoid have also been replaced since the light went on.

While driving the following day the check engine light (CEL) came on and when checked at pep boys read P0403 (no other codes for low EGR flow, etc.). Now, the EGR solenoid is the newest non-regular maintenance item under that hood because the same code came up a couple of years ago (a new solenoid from pep boys fixed that lickety split) so I wasn't overly concerned that it had popped up again, but a bit frustrated that the solenoid only lasted as long as it did. Also, since the light popped up, I have replaced a couple of vacuum lines with some generic 4mm ID (5/32", I think) rubber vacuum hose, but that just headed off what looked like some potential future problem leaks.

Now, here I am a couple of weeks later having tried 4.5 new solenoids (Amazon sent me one with the wrong wiring harness clip so I couldn't verify that it was connected when it didn't work), and thrown some other "just in case" parts at it (new EGR valve and flow sensor, but these may be returned, but may just end up keeping them on, we'll see how things work out). I'm getting a solid reading from the hot lead on the solenoid harness at idle and during static revving, but I can't seem to get anything on the ground pin.

I've cleaned the connections and the larger pin block going into the top of the firewall to no avail. Should this read as a fluttering ground signal all the time, is it only grounded exactly when it wants the solenoid to open the EGR? What can I do to confirm that it should read grounded so I can know one way or the other whether there is a break in the line? I can't find my multimeter (or just dreamed that I picked one up last year). I'm also curious as to whether or not there's a good way to bench test the solenoid. I don't really get a reaction when I hook it up to 12v directly like I do with a vacuum solenoid from my Saab where there's an audible "click."

Is the wire harness for the solenoid a known weak spot? I've found two potential donors at the local junk yard that I can cut the wires out of to play around with/solder a new one in if that's something that the consensus deems may solve my cause. I also had an ABS light come on not too long after the CEL, but when I reset the CEL the ABS light went away and never came back (it only came on when I hit a big expansion joint on a highway bridge, no braking issues since it's been reset and ABS seems to be fully functional, per gravel road test). I still can't seem to read any ground signal at the solenoid harness at idle or with throttle input. I'd like to fix it, but don't want to start digging into the wires blind.