2004 6.0l GPCM test?
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2004 6.0l GPCM test?
Hey guys, I have a question about testing the glow plug control module on a 2004 psd. Last week it dipped to 35F and below here and I have been having troubles starting in the morning. When I do actually get it started cold it puffs some white smoke for 15 seconds or so.
So I have tested the FICM and it has a good 48 volts both key on and starting/running.
I checked the ohm of the glow plugs using methods i found by googling. They all checked correct. I could also tell that the harness was too clean to be old so I am assuming that the previous owner had the glow plugs and harnesses replaced not too long ago.
My next step is to check the GPCM. No unfortunately I do not have a scanner. I was hoping I could use my volt meter to perform checks on the unit. I did see that someone had poked into a pink wire with a green stripe on the black connector going into the GPCM. I did use my volt meter to check the voltage going to the glow plugs at the 4 prongged connector on top of the valve covers. The results were `5.3-5.7 volts at all times. It didnt change with cycling the key, just a steady reading which seems weird to me.
So if anyone knows how to test the GPCM please chime in.
Thanks Josh
So I have tested the FICM and it has a good 48 volts both key on and starting/running.
I checked the ohm of the glow plugs using methods i found by googling. They all checked correct. I could also tell that the harness was too clean to be old so I am assuming that the previous owner had the glow plugs and harnesses replaced not too long ago.
My next step is to check the GPCM. No unfortunately I do not have a scanner. I was hoping I could use my volt meter to perform checks on the unit. I did see that someone had poked into a pink wire with a green stripe on the black connector going into the GPCM. I did use my volt meter to check the voltage going to the glow plugs at the 4 prongged connector on top of the valve covers. The results were `5.3-5.7 volts at all times. It didnt change with cycling the key, just a steady reading which seems weird to me.
So if anyone knows how to test the GPCM please chime in.
Thanks Josh
Fleet Owner
Joined: Apr 2012
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From: Spanaway
You going to need a scan tool. The GPCM reports to the PCM.
You may be able to get some info by using a DC amp meter
if you can access each plug wire one at a time. I don't have the
link but I posted some info about the glow plug system some
time last year I think. It gave some info about what you should
be seeing with a meeter. I'll look and see if I can find it.
Sean
NOTE : Here is the info I posted. Guess I posted that last March.
https://www.ford-trucks.com/forums/1...ce-manual.html
This info was from the 06 service book.
You may be able to get some info by using a DC amp meter
if you can access each plug wire one at a time. I don't have the
link but I posted some info about the glow plug system some
time last year I think. It gave some info about what you should
be seeing with a meeter. I'll look and see if I can find it.
Sean
NOTE : Here is the info I posted. Guess I posted that last March.
https://www.ford-trucks.com/forums/1...ce-manual.html
This info was from the 06 service book.
Last edited by Yahiko; Oct 26, 2013 at 10:59 PM. Reason: LINK
Postmaster
Joined: Jan 2005
Posts: 4,424
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From: BC Canada
At those colder temps you will see a bit of white smoke, it's the moisture in the damp,air in the exhaust and from first starting with limited heat, entering into the atmosphere and condensing. If you don't have codes, I seriously doubt you have glow plug or gpcm issues. Check your FICM logic power cold, pre start and during start, that is seemingly more likely an issue. Does it start better when you plug in the block heater for 4 hours prior to start? All just suggtions, those codes will point you in the right direction, without codes you can spend a lot of money guessing and trying parts.
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If you're having a GPCM problem you should get a CEL. All you need to do is get it code scanned and you'll find out if you have any kind of glowplug problem.
Check your FICM logic power cold, pre start and during start,
Does it start better when you plug in the block heater for 4 hours prior to start?
Are there any other things I should consider for a hard cold start. I am about 600 miles away from my first oil change. Would anyone recommend a lighter oil such as a 5w instead of a 15w?
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