U0106 Loss of Comm with GPCM

J_Stone06

Wasn't me...🥴
Oct 13, 2012
347
3
18
Nowhere, KS
First time I have had this issue. I looked on a few threads here but I can't seem to find the GPCM. It has been consistently 100+ where I am currently at, so temps are not my worry for starting. Where is the actual module located? Does anyone know the P/N and/or pricing for one? Obviously once I locate it, I will check the connections. Fuses? Just a little help and advise would go a long way, thanks gents.

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Ron Nielson

Active member
Oct 11, 2009
702
118
43
Berryton, KS
98089571 full dealer price $273.66. NO doubt you can find it for much less.

Glow Plug Control Module Programming and Setup

The following service procedures require either a programming or a setup event performed for a complete repair.

GPCM Replacement

If the glow plug controller (GPCM) is replaced, the following procedures must be performed.

Fuel Injector Flow Rate Programming for fuel injector flow rate programming

Setup for Component Replacement

The replacement of some components will require a setup procedure for complete repair.

If any of the following components are replaced, the Fuel Injector Flow Rate Programming must be performed. Refer to Fuel Injector Flow Rate Programming.

Fuel injector
Engine control module (ECM)
GPCM

gpcm.gif
 

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J_Stone06

Wasn't me...🥴
Oct 13, 2012
347
3
18
Nowhere, KS
98089571 full dealer price $273.66. NO doubt you can find it for much less.

Glow Plug Control Module Programming and Setup

The following service procedures require either a programming or a setup event performed for a complete repair.

GPCM Replacement

If the glow plug controller (GPCM) is replaced, the following procedures must be performed.

Fuel Injector Flow Rate Programming for fuel injector flow rate programming

Setup for Component Replacement

The replacement of some components will require a setup procedure for complete repair.

If any of the following components are replaced, the Fuel Injector Flow Rate Programming must be performed. Refer to Fuel Injector Flow Rate Programming.

Fuel injector
Engine control module (ECM)
GPCM

View attachment 46171
Thanks for the reply. Can I just program full with autocal to remedy the programming needed?

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J_Stone06

Wasn't me...🥴
Oct 13, 2012
347
3
18
Nowhere, KS
Will my autocal tuning work for the reprogramming needed for the GPCM?

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I'm confused as to what my next step should be? Do I have to reprogram the ECM with the same flash of EFI live tuning or how does the programming work?

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Hambone

Always learning
Jan 24, 2016
572
0
16
Florida
I'm sure that's the proper procedure but I've replaced a couple before and never did a reflash
Also currently have the hog truck running without one and just put electric tape over the dash light lol
 

fc8464

Member
Jun 26, 2012
71
0
6
Fairbanks, Alaska
There is a PI for this setting false codes. Have you had the dealer perform a updated calibration yet? There is also a PI to check connector 2500 and 2501 for being pinched at frame and body.Fred
:hug:
Subject: No Start/No Crank - Loss Of High Speed GMLAN Communication
999999995.gif
Models: 2007-2008 Chevrolet Silverado2007-2008 GMC SierraThis PI was superseded to update model years. Please discard PIT4444.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:Some owners may comment of a no crank and/or no start concern, which may be an intermittent or hard fault. If intermittent, when viewing DTCs there will be communication codes for the High Speed GMLAN modules. If the concern is current, the Tech 2 will not be able to communicate with any High Speed GMLAN modules.
Recommendation/Instructions:This concern could be caused by the High Speed GMLAN circuits (2500 and 2501) shorted to ground or together. Reports have been received of these circuits being pinched between the truck box and frame near the terminating resistor as shown in the picture below, see SI document 1858913 for location. To repair this concern remove the harness from between the box and frame and repair any damaged circuits.
1991762.gif

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer
 

J_Stone06

Wasn't me...🥴
Oct 13, 2012
347
3
18
Nowhere, KS
There is a PI for this setting false codes. Have you had the dealer perform a updated calibration yet? There is also a PI to check connector 2500 and 2501 for being pinched at frame and body.Fred
:hug:
Subject: No Start/No Crank - Loss Of High Speed GMLAN Communication
999999995.gif
Models: 2007-2008 Chevrolet Silverado2007-2008 GMC SierraThis PI was superseded to update model years. Please discard PIT4444.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:Some owners may comment of a no crank and/or no start concern, which may be an intermittent or hard fault. If intermittent, when viewing DTCs there will be communication codes for the High Speed GMLAN modules. If the concern is current, the Tech 2 will not be able to communicate with any High Speed GMLAN modules.
Recommendation/Instructions:This concern could be caused by the High Speed GMLAN circuits (2500 and 2501) shorted to ground or together. Reports have been received of these circuits being pinched between the truck box and frame near the terminating resistor as shown in the picture below, see SI document 1858913 for location. To repair this concern remove the harness from between the box and frame and repair any damaged circuits.
1991762.gif

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer
Thanks for the reply, no I've been trying to stay away from dealers as I've lost my a$$ to them in the past and they did more damage than good. I can't open any photos that may have been posted with your post.

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BrandonLLY

Member
Apr 23, 2014
116
8
18
Need to take to the dealer and have it programmed, no way around it besides a delete. I have the same code in my truck. GP light stays on for 30 seconds before it turns off after i replaced my module. If you have efi live, you need to flash back to stock. Then once the dealer plays with the ecm you need to save the new stock program and then flash back with your dsp 5
 

J_Stone06

Wasn't me...🥴
Oct 13, 2012
347
3
18
Nowhere, KS
Need to take to the dealer and have it programmed, no way around it besides a delete. I have the same code in my truck. GP light stays on for 30 seconds before it turns off after i replaced my module. If you have efi live, you need to flash back to stock. Then once the dealer plays with the ecm you need to save the new stock program and then flash back with your dsp 5
I don't have EFI tuning rights with the tunes on my truck...I'm a noob to all that stuff.

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