No power to FICM . . . occasionally

[Hemicbx]

I've had a few no starts lately. Each time, I can cycle the key (sometimes twice) and it will fire right up. Each time this happens, I get a P0611 and a P1378.

I've got an edge insight with the latest software in it so I can see FICM voltage and HPOP. I've now been allowing the insight to fully boot prior to starting the truck so that I can better see what's going on. HPOP builds very quickly; I have little concern there.

The FICM voltage on my truck has always been 48 or 48.5V; never showed a decrease. However, on some of my recent starts, I've noticed that the FICM voltage displayed on the Insight is 1.0 or 1.5v prior to cranking. Obviously, it won't fire up like that. I then cycle the key and I see a full 48V prior to cranking and it starts immediately.

It is my belief that the displayed 1.0 or 1.5v on the insight is really a measurement error and that the real voltage is zero. I believe that the FICM relay is not closing, therefore providing no voltage to wake up the FICM. This would also explain the P0611 & P1378 codes since the FICM is seeing low (or no) voltage during an attempted start.

The truck is a stock 05.

Thoughts or ideas?

Hemicbx
York, PA

[Hemicbx]

I wanted to come back around and close the loop on this one. I did put a new FICM relay in the truck 2 weeks ago and have not had a no start issue since. I still occasionally allow the Insight to fully boot up prior to start and it's always solid @ 48v.

Today I popped the old relay open and tried to get a look at the contacts. Couldn't really see all that much, so that's a little inconclusive.

This is the second time now that the Edge Insight has either alerted me to or helped me solve a problem. Worth every penny

[Ronisonce]

You've just given me one more reason to purchase the edge insight.

[Hemicbx]

Here's another:

Back in January I had to go about 100 miles to pick something up. I had been noticing that the battery light would flicker a little right after start, but then it'd go out.

I set the edge to show me battery voltage and started out to pick up my stuff. I saw that battery voltage wasn't up to snuff, but figured I'd drive a little anyway. About 10 miles from home, battery voltage had steadily trended downward and the battery light came on solid. New alternator, done. Most importantly, I didn't end up sitting on the side of the PA turnpike.

Get one. With the latest software update providing HPOP pressure and FICM voltage, it's even better!

[Ronisonce]

Yea, it just seems like a necessity. I plan on keeping my truck for years to come. Where did you purchase it if you don't mind me asking? I was thinking of buying from xtremediesel.com.

[Hemicbx]

Yes, mine came from Xtremediesel. Good service, fast shipping. There are loads of other good vendors out there who are also site sponsors. I think pricing is pretty consistent from one to the next.