Duramax Check Engine Light/ Glow Plug Problem?

[RidinHigh98]

My dad has a 2006 duramax and the other day the check engine light came on. Looked in the book and it says it has a problem with emissions. Also he noticed that when you first go to start it up after its been sitting awhile the glow plug light just stays on.What could be the problem?

[AZdragger]

Didn't know the D-max's used glow plugs? Thought they used an inline heater or something (forgot what it's called)

[Farmer98]

They use glowplugs. Get us the code numbers and we can go from there

[foreman00081]

P0380? mine has that code. "glow plug heater circuit "A" malfunction" its a problem with either a bad glow plug or several or the glow plug circuit relay. pretty common in the LB7 dmax's at least. not sure about the LBZ's but it could be.

[RidinHigh98]

He is going to get it checked when he has time. I just thought it might be something common. The glowplug thing only happends when the engine is cold. When it has been run within about the last 8 hours it doesnt do it at all for some reason. The check engine light stays on nomatter what. It runs fine though

[foreman00081]

i dont think the glowplugs light when the engine is already warm so that could be why the light doesnt come on. mine does the same thing but my glowplug light never stays on like your describing. my engine light does come and go though but during the colder months it was on all the time. seems that when the temps are in the 60's, 70's or above the engine light stays off a lot more which i think is because the glowplugs are not being used so they dont trigger the code.

[RidinHigh98]

Yeah they rarely even come on during the hot months it seems. Even in winter they only last a few seconds. He will have to get the code ran.

[foreman00081]

in the winter mine stay on for 5-10 seconds before i can start it depending on how cold it is. i couldnt believe how fast they were the first time i drove an 06 though. even in 10 degree weather they were only on for a couple seconds, and the truck had been sitting for weeks.

[RidinHigh98]

Yeah I could believe how quick they are. Im used to waitin 15-25 seconds for the old cummins and 7.3's to warm up

[gr8shot]

IIRC there is a TSB for the glowplug relay, or module or something. It's specifit to the LBZ as well I think. It's something like reprogramming the glowplug control module. Just have him take it into the stealer. They should know whats going on and have him out the door in no time. I've been looking at buying an LBZ for a little while now... most of the VIN's I have had ran have that in the warranty work part.

[dozerboy]

X2 go ASAP if the GPs are staying on to long the tips will melt off fall inside the cylinder and then by by engine.

LBZ also have a bit of EGR issues should be P0406 IIRC???

[gr8shot]

yeah, getting the egr motor replaced is a fairly common thing. If they do that, avoid the reflash. It's been dropping fuel mileage pretty bad.

[dozerboy]

I don't know that a mileage drop as anything to with the reflash it just makes the EGR cycle open and closed more IIRC. I believe I had the reflash, but my mileage never dropped.

[gr8shot]

The reason I say that is I saw a poll on DP a couple months back asking about EGR replacement and subsequent reflash and mileage drop. And almost everyone had a drop in mileage after it. But it didn't ask about just EGR replacement or just reflashed, so you may be right.

[RidinHigh98]

we got it scanned and it said it is a malfunction in the glowplugs