2007 LBZ Duramax - no Glow Plug Light in Below Zero?

Jorg Jorgenson

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Hey All, so I know this isn't the right Forum to be asking my question on but I haven't gotten any help on other dedicated Truck Forums (dinks..) and with any internet research on my issues. Since sledders are awesome I thought I'd try reaching out to fellow duramax owners:

I bought a used 2007 classic duramax back in April 2019 with a bag glow plug (#5 if I recall) and check engine code (due to the glow plug, I scanned & confirmed it was the only code). I drove the truck most of the summer with it like this since it didn't bother me and no cold starts needed for the summers in Alberta. The coil light would on occasion be lit telling me to wait before cranking over the engine, which I did. I figured the coil light was coming on during the summer temps largely due to the bag glow plug.

I replaced the bad glow plug in September 2019. After replacing I cleared my CEL and it never did come back (voila, problem fixed!), but I also noticed that the coil light was no longer showing up when going to start the truck. It is now December and we are getting temps around -15 degree C in the mornings and I STILL am not seeing the glow plug light show up?? Most people said they start seeing it right around the freezing mark, even if it's only for a split second. I will wait until my CEL light goes away to crank the truck over since I am afraid to star tit too early and being doing damage. Is it possible that there is a fuse or relay that went bad for the glow plugs? The truck doesn't have any issues starting no rough starts or cranks seems like pretty healthy/strong cranking in -15 even when not plugged in.

A few more items probably worth mentioning, I have a PPE Xcelerator Standard Tuner (set at stage 2 90hp) that I tuned the truck with and check my codes with. Has an AFE air intake, MBRP exhaust. Also when I put my new tires on in the fall I re-calibrated my tire size and 1 week after doing so I got a DTC 2610 code (something about engine timer) looked it up seemed to be no big deal, so I cleared it and it has never come back since.
 

sirkdev

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Hey All, so I know this isn't the right Forum to be asking my question on but I haven't gotten any help on other dedicated Truck Forums (dinks..) and with any internet research on my issues. Since sledders are awesome I thought I'd try reaching out to fellow duramax owners:

I bought a used 2007 classic duramax back in April 2019 with a bag glow plug (#5 if I recall) and check engine code (due to the glow plug, I scanned & confirmed it was the only code). I drove the truck most of the summer with it like this since it didn't bother me and no cold starts needed for the summers in Alberta. The coil light would on occasion be lit telling me to wait before cranking over the engine, which I did. I figured the coil light was coming on during the summer temps largely due to the bag glow plug.

I replaced the bad glow plug in September 2019. After replacing I cleared my CEL and it never did come back (voila, problem fixed!), but I also noticed that the coil light was no longer showing up when going to start the truck. It is now December and we are getting temps around -15 degree C in the mornings and I STILL am not seeing the glow plug light show up?? Most people said they start seeing it right around the freezing mark, even if it's only for a split second. I will wait until my CEL light goes away to crank the truck over since I am afraid to star tit too early and being doing damage. Is it possible that there is a fuse or relay that went bad for the glow plugs? The truck doesn't have any issues starting no rough starts or cranks seems like pretty healthy/strong cranking in -15 even when not plugged in.

A few more items probably worth mentioning, I have a PPE Xcelerator Standard Tuner (set at stage 2 90hp) that I tuned the truck with and check my codes with. Has an AFE air intake, MBRP exhaust. Also when I put my new tires on in the fall I re-calibrated my tire size and 1 week after doing so I got a DTC 2610 code (something about engine timer) looked it up seemed to be no big deal, so I cleared it and it has never come back since.

tex78 is your man for this question.
 

tex78

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Well first off, after your glow plug replacement you need a scan tool to turn on the glow plugs and the gpcm needs to see the amps draw and resistance to turn that hole on, which it will look at all 8 to see if there good, and show you bad one again possibly

The p2610 is from unhooked battery's or they have gone dead at one point

Possibly bad glow plug control module I guess too
 

Jorg Jorgenson

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Well first off, after your glow plug replacement you need a scan tool to turn on the glow plugs and the gpcm needs to see the amps draw and resistance to turn that hole on, which it will look at all 8 to see if there good, and show you bad one again possibly

The p2610 is from unhooked battery's or they have gone dead at one point

Possibly bad glow plug control module I guess too

Yes I had unhooked the battery to change the glow plugs as I saw that as a recommended tip somewhere on a separate forum. But that was many weeks before I saw that code pop up.

What kind of scan tool can be used to manually turn them on? I hadn’t heard of this before.

I haven’t checked fuses for the gpcm yet but I will for sure, it just seems to be starting and cranking so easily go the plugs to not be working... no issues starting whatsoever just don’t see the light. Did you have those same symptoms as me?
 

tex78

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Yes I had unhooked the battery to change the glow plugs as I saw that as a recommended tip somewhere on a separate forum. But that was many weeks before I saw that code pop up.

What kind of scan tool can be used to manually turn them on? I hadn’t heard of this before.

I haven’t checked fuses for the gpcm yet but I will for sure, it just seems to be starting and cranking so easily go the plugs to not be working... no issues starting whatsoever just don’t see the light. Did you have those same symptoms as me?
Gpcm is at the lh rear on the engine top

Need a good big scan tool to turn them on
 

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If you’re plugging it in and the coolant temp comes up, the glow plugs won’t heat as well.
 

Jorg Jorgenson

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If you’re plugging it in and the coolant temp comes up, the glow plugs won’t heat as well.

I've only been plugged in a handful of times. When I cold start in -10 after sitting outside for 9 hours, no glow plug light comes on.

I do also have an aftermarket remote start. It was always on the truck but I did not have the fob for remote starting it until Nov 11th which was after I changed out the glow plugs. I read somewhere else that they suggest disconnecting any aftermarket starters before changing GP's out but I would assume by disconnecting the battery this takes care of that? I'm wondering if there is a setting within the remote start that would disable the GP light so the truck can start remotely...?
 

Jorg Jorgenson

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Gpcm is at the lh rear on the engine top

Need a good big scan tool to turn them on

Noted, thanks Tex.

Like I said earlier though, wouldn't this issue of no power to the GP or a bad GP cause the GP light to come on or stay on longer than normal? Because I am having the opposite issue of it never turning on for me
 

tex78

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Noted, thanks Tex.

Like I said earlier though, wouldn't this issue of no power to the GP or a bad GP cause the GP light to come on or stay on longer than normal? Because I am having the opposite issue of it never turning on for me
But it may limp itself if say 2 or 3 plugs are inop

Could make sure ya got power to main big single wire that feeds it

Now if I recall the lbz is regular 12 volt plugs, the new ones are up in the 24-48 volts, from ecm
 

brian h

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But it may limp itself if say 2 or 3 plugs are inop

Could make sure ya got power to main big single wire that feeds it

Now if I recall the lbz is regular 12 volt plugs, the new ones are up in the 24-48 volts, from ecm
yes the lbz is 12 volt
 

LMLCHEVY

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Easy way to check that your gpcm is working is to unplug a couple glow plugs. You should get a cel for that indicating a problem and proving that it’s working and your light for the glowplug may just be burnt out.

A tech 2 or maybe a higher end snapon scanner may also be able to test them as tex78 previously mentioned.
 

Jorg Jorgenson

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So I went out today to start the truck with my key not the remote start. -3 it said. I caught a glimpse of the glow plug coil light for about 2 seconds before it went out. I don’t know how I missed it before ??? This may have been a non-issue all along...
 
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