Glow plug control module source

[rapidoxidationman]

For an LLY (2005)...

My CEL came on a couple of days ago: P0670 is the only code present. There's power to the glow control module from the battery (the single thick wire going to the module) and the plugs all seem good as tested from the wiring harness pins 1-4 and 7-10 at the module (ranges from 1.2 to 3.4 ohms; number 5 is the high one IIRC). Good ground on pin 11. Truck still starts with a couple extra seconds of cranking (35 degrees outside), but winter will eventually come around here again.

NAPA wants $206 for a new module. Anybody got a better source? I haven't priced it from GMPartsDirect, but nor can I find the OEM part number to plug into the website.

Kennedy, do you have this available? Couldn't find it on your website either.

Thanks in advance...

Edit: Found what I believe to be the proper GM p/n: 97379635
ebay has it for about $110, gmpartsdirect is about $95... I'd be ok with getting it from a known good source...

[rapidoxidationman]

Picked one up at the dealer for $159 plus tax. Putting it in now and will cycle the ignition a few times to make sure the code is gone.

Edit: P0670 is gone with the new control module. I'll bet it stays gone after tomorrow morning's cold start.

Yesterday while I was diagnosing, I started the truck with both circuits (large battery + line in and the gang connector) unplugged from the module and caused a U0106 code to be thrown. It doesn't trigger the CEL and is said to be "network lost communication with control module". Duh. It doesn't clear with the Torque Pro app, but given that it doesn't light any lights on the dash I'm not worried about it. We'll see what happens after the day is done tomorrow - I'm thinking it will be erased after several on/off cycles with no glitches noticed by the ECU.

[rapidoxidationman]

Several on/off cycles later:
The P0670 code is gone.
The U0106 code which was "pending" is now "current" and IS illuminating the CEL. Clearing the code turns the light off, but it turns back on the next time the engine starts.

Suggestions? Am I just being impatient and it'll sort itself out after the next COLD start tomorrow morning?

[DmaxMaverick]

If the lamp is on, and it's an active code, then it's still happening. It isn't receiving feedback voltage from the module, or it's erroneous data it hasn't accepted yet. It should clear itself after a "good" cold start. If not, check connections, or you have a bad or wrong module (CA/NE emissions, for example). Interesting that the lamp is on. It's only supposed to MIL after repeated occurrences.

[rapidoxidationman]

The parts desk gave me the replacement based on the last 8 digits of my VIN, so it ought to be the right one- it is the same in shape and part number.
The multi wire connector MAY have not been fully seated. It is now and tomorrow will be telling me if it's fixed or if I have more diagnostics to do...

[rapidoxidationman]

The CEL was on this morning for the first two starts. Out now, and it seems to be out for good - I started the truck at least 20 times through the course of the day.

[DmaxMaverick]

Just "starting" isn't good enough, for most emission system faults. They require X number of "warming cycles" (usually 2, to snuff the lamp). Meaning, the engine temp must start at a maximum-minimum temp, and reach a minimum-maximum temp (with no repeat fault) before it counts as a "cycle". The code in history may remain for as many as 40 cycles. EPA rule, ya know....

[rapidoxidationman]

Learn something new every day. Thanks DMax, I thought "start" cycles was enough but it makes sense that "warming" cycles would be what the computer is looking for. At any rate, the CEL was out yesterday and the u0106 code is hopefully now classified as "history" instead of "pending" or "current". May it be pushed into oblivion over the next 39 days...

(fingers crossed that this morning's cold start doesn't show me any lights I don't want to see...)