Glow plug module , no check engine

[Veikra]

Ok, I changed all the glowplug and still they wont light.

When we put the scanner it says something along the lines of glow plug control module open circuit .
Basically, my glowplugs dont light up.

I disconnected the power wire from the module and it tests fine.

The check engine doesnt light up ...

Im not finding lots of infos on lly module, plenty on 2006 up and 2003 down.

I can't use the truck as it's winter.

I'd like a wiring diagram of that module, all the small wires, so i can probe around

 

[Veikra]

I got the wiring pinout for the module. I will test tomorrow.

Dealer wanted 25$ to print me the pinout. Had to talk to the Dealership Manager to get it free.

Do your dealer charge for that? One would think it comes as support after sale...

 

[Kansas2500hd]

Are none of them lighting?


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[Veikra]

absolutely none are working . it's cold and wont start without block heater after a cold night.

-8c is the coldest it will start at, with rough idle and white smoke.

Pretty sure either the glow plug controller isnt working correctly, or the wiring to it has a problem

 

[chevyburnout1]

What is the exact code number? Is the main power supply wire actually have power? Mega fuse isn't blown?

 

[Veikra]

Po670 is the code IIRC Main power is okay so the fuse is good

Made in germany...

Still no check engine light, although the code is there and ive read it should throw a CEL...

 

[Veikra]

Replaced module. Module gets power and wirring to all glow plug and glowplugs are good. Still very rough start at -10C ~20F and below. Truck Runs good when warm.
I don't see a huge increase in voltage when the WTS cycle stops...

Could it be related to my WOT limp ? Or a bad ECT sensor ? Just throwing ideas while I wait for my scanner

 

[Veikra]

Ok, was -11c without windchill. took 20tries to start it. No glowplugs.

Re-briefing:

Ignition 12V (pink) to glow plug controlleur module is good.
Ground (pink with colored line) Good as well.
All 8 pins to glowplugs test fine with testlight with other lead on battery +
Glowplug controller is new.
Large wire from 175 fuse has 12V.

Maybe there's corrosion or voltage drop under load of this large cable.
I'll keep updating as I find more infos.

 

[Veikra]

Rechecked connections, cleaned the fuse's contact. PLugged into the large power wire and twisted the fusible link to see if there was a break in there. None found.

Unless im missing something, the new glowplug module is also bad. The wait to start light functions correctly.

 

[MidniteMetal]

Viekra:

Did you figure out what was the issue with your glow plugs? I'm having the same trouble with mine. Everything tests fine but yet it's still hard to start when it's cold

 

[Veikra]

Never found the issue, the new module started working again by itself. No amount of code clearing could make it work, so I guess after x amount of starts it cleared up.

Truck started all winter

 

[ssg_johnson07]

Veikra,
I also have the same issue. Where is the module located? I cant seem to find anything that shows exactly where the module is located.

 

[Veikra]

Veikra,
I also have the same issue. Where is the module located? I cant seem to find anything that shows exactly where the module is located.

It's on the back of the driverside head. It's square, black and has a round thing in the middle. 2 plugs, a big one with lots of wire, and a small round one with a single power wire.

My trucks lights all 8 glowplugs, and no codes presents. I think the glowplug were causing the module to stop responding to the ecu. It took a while for the new module to finally decide to work after replacing all 8 plugs and the module itself.