Possible Glow Plug Control Module Issue?????
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Possible Glow Plug Control Module Issue?????
I have already searched a lot of the other forums for an answer and came up short. The truck is an 06 F-350 6.0 w/144,000 miles. I went to go to work the other day and my check engine light came on. Took it to Advance Auto and it came back with Glow Plug circuit #2 fault and it showed that the code had been thrown 3 times. I did the OHM test on the glow plugs and they all checked out at 0.7 ohms, which lead me to believe it was the GPCM. Since Advance forgot to clear the code, I unhooked the batteries for 30 sec to clear the code and restarted the truck. No check engine light this time. Drove the truck around for a bit as well as turning the ignition on and off multiple times. Still no light. Not that I'm complaining that the light isn't coming back on but I'm lost as to what was causing the code to begin with or could it be just queer-trons? Any help would be much appreciated. Thanks 
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I checked for corrosion when I had it all unplugged and it was clean as a whistle. I guess as long as I don't get another CEL I'm good but trying to figure out what gave me the code in the first place is a little bit of a curve ball. Usually on parts like that it either works or it doesn't. We'll see what happens over the next few days. Thanks for the info.
Laughing Gas
Joined: Jan 2010
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From: Florida
I've had a few of these glow plug codes - mine have gone off for a while too, but they always come back on. In my case it has always been the glow plugs. They are pretty easy to swap and cheap. GPCM is over $100. I agree with the dielectric grease. At least once the glow plug tested OK but the light stayed off after a new one (the other time I did not bother with the testing, just swapped it out). If the light stays off, I would not worry about it. Maybe it was a bad connection that you fixed just doing the testing - disconnect, reconnect.
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I've had a few of these glow plug codes - mine have gone off for a while too, but they always come back on. In my case it has always been the glow plugs. They are pretty easy to swap and cheap. GPCM is over $100. I agree with the dielectric grease. At least once the glow plug tested OK but the light stayed off after a new one (the other time I did not bother with the testing, just swapped it out). If the light stays off, I would not worry about it. Maybe it was a bad connection that you fixed just doing the testing - disconnect, reconnect.
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From: Saratoga Springs,UT
That leads me to beleive it is the GPCM as well
But the Circuit might be Open Only when cold so it may take a cold soak cycle or 2 to throw the DTC Again
So if you checked (OHM) them when Hot Might be good to check them Cold After 12 hours cold soak
Hot/Cold & Expaned/Contract does weird electrical stuff
Could be a wire Chafe to But if its really been triggered 3 times its coming back so Keep the Parts
And write down the exact DTC next time
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That leads me to beleive it is the GPCM as well
But the Circuit might be Open Only when cold so it may take a cold soak cycle or 2 to throw the DTC Again
So if you checked (OHM) them when Hot Might be good to check them Cold After 12 hours cold soak
Hot/Cold & Expaned/Contract does weird electrical stuff
Could be a wire Chafe to But if its really been triggered 3 times its coming back so Keep the Parts
And write down the exact DTC next time
But the Circuit might be Open Only when cold so it may take a cold soak cycle or 2 to throw the DTC Again
So if you checked (OHM) them when Hot Might be good to check them Cold After 12 hours cold soak
Hot/Cold & Expaned/Contract does weird electrical stuff
Could be a wire Chafe to But if its really been triggered 3 times its coming back so Keep the Parts
And write down the exact DTC next time
When I originally tested the glow plugs the truck had been sitting for 3 days with out running. I inspected for possible wire chaffing when I was under the hood but couldn't really see anything that led me to believe that might be the problem. The code I was getting was P0672 - Glow Plug no. 2 circuit fault. I know this is probably in another thread somewhere but any way to test the GPCM? I absolutely hate trying to diagnose electrical problems
Fleet Owner
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From: Spanaway
Were you thinking about this post?
https://www.ford-trucks.com/forums/1...ce-manual.html
Here is what I had to say,
Sean 
https://www.ford-trucks.com/forums/1...ce-manual.html
Here is what I had to say,
All this information comes from the 2006 Service Manual.
Glow plug on time is dependent on oil temperature and altitude. The GPCM will
command the glow plugs on for 1 to 120 seconds. The GPCM does not operate
if the oil temperature is above 55C (131F)
It looks like the GPCM is really 2 units in one box.
Glow plug to ground 0.1~2 Ohms
Glow plug connector to GPCM connector Less that 5 Ohms
Pin #3 on both is the VBattery
Green connector
pin #1 is gp#5
pin #2 is gp#7
pin #6 is gp#1
pin #7 is gp#3
pin 8 goes to the PCM
pin 9 goes to the PCM
Black connector
pin #1 is gp#6
pin #2 is gp#8
pin #6 is gp#2
pin #7 is gp#4
pin 9 goes to the VPwr
Enjoy
Sean
Glow plug on time is dependent on oil temperature and altitude. The GPCM will
command the glow plugs on for 1 to 120 seconds. The GPCM does not operate
if the oil temperature is above 55C (131F)
It looks like the GPCM is really 2 units in one box.
Glow plug to ground 0.1~2 Ohms
Glow plug connector to GPCM connector Less that 5 Ohms
Pin #3 on both is the VBattery
Green connector
pin #1 is gp#5
pin #2 is gp#7
pin #6 is gp#1
pin #7 is gp#3
pin 8 goes to the PCM
pin 9 goes to the PCM
Black connector
pin #1 is gp#6
pin #2 is gp#8
pin #6 is gp#2
pin #7 is gp#4
pin 9 goes to the VPwr
Enjoy
Sean
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