LBZ Glow Plug

[BigDogYJ]

So yesterday its about 86F outside and truck had been sitting outside in sun all day. Get in to start it and noticed the CEL. checked the code P0675.
Glow Plug Circuit #5. Check the wiring, looks good. Pull the plug no tip missing. Check the resistance. 2.33 ohms. According to PIP3586E if any glow plug is measuring more than 1 ohm, replace all 8.
The "driveability" tech at the local dealer says they only have replaced the "bad glow plug" in the past without a problem. Not all 8 as the tSB states.

What do you guys think? I am thinking to just replace all 8 as a precautionary measure. he doesn't think its necessary and considers it a waste of money.

 

[CtChevy427]

I would bet you would be fine with only replacing the one that is bad. If another drops off then I would replaced the remaining ones.

 

[Ed HD]

What do they cost? If it's not that much, I'd replace them all. However, if they're like $20 or more, just replace the one needed.

 

[BigDogYJ]

they were $18 through my buddy at a GMC dealer. Normal Retail at dealer is like $33 each. They only had one in stock. I replaced the #5 GP and cleared the codes with a tech 2 from another friend and all seems ok now. I checked the data readings through the Tech 2 and the other GP's were measuring 17.5 18.5 AMPS and the #5 was 0 Amps. Also all of the other GP's were measuring 0 Ohms, and #5 was 28ohms. so it appears it was just that one that was bad.

It seems happy today, no code or delayed WTS light this morning. So if I get another that dies, I will replace all the rest of them.

 

[trotorx2]

Mind if I jump in and bump this?

I had my first check engine light today and it was P0676 #6 cyl glow plug. How hard are they to replace? And how soon should I fix it? I'm away from home at work.

 

[BigDogYJ]

Not hard at all. just remove the inner fender liner, remove the nut/wire then unscrew the glow plug. I cant remember the size of the sockets required, but the nut for the wire was really small 5/16" i think and glow plug may be around 10mm or so.
I fixed it ASAP due to the posts I read about the early models breaking off a tip in the cylinder.
Mine didnt break off, but I changed it 2 days after the code appeared.
How many miles are on it?

 

[trotorx2]

I must be goin crazy, I answered you yesterday...I thought.

I have around 45,000 miles on the motor. I'm still getting the CEL but when I check it with my predator now it shows no codes found but I can turn off the CEL by clearing the codes. The light comes back on later though. I guess I need to go have it read with a better reader.

BTW which cyl. is #6?

Thanks

 

[BigDogYJ]

I can't remember off hand which cylinder is #6.
I'll look in my AllData to see if I can find it.

The light takes I believe 2 or 3 warm up cycles of the glow plugs before it trips the CEL. once you clear it, they become sort of temp until it recognizes the problem 3 times in a row, then turns on the CEL. I cleared mine once, then after a few start ups it came back on. then changed the #5 GP the following day and cleared it. Never came back.

 

[trotorx2]

Mine is still under warranty so I'm going to call a shop here at work and see if they can replace it, if not hopefully I'll get back to Texas next week and will get it fixed at home.

 

[BigDogYJ]

u should be ok. I remember reading something about the LB7s had the issue from the factory or very early in life (less then 10k miles) because the factory was testing them with a full 12volts which was damaging them and causing the tips to break off in the cylinder. I believe they are only a 4 or 5 volt plug. So the later LLY and LBZ never saw the full 12volts. so it may just be normal wear. you should be good till you get back home. it only took me 15 minutes to change and it cost around $20. not bad.

 

[trotorx2]

Thanks for the help. I'm gonna drive it till I get back home then call the dealer there. I may just fix my self instead of going thru the hassle of going to the shop.

 

[RI Chevy Silveradoman]

There was also a Glow Plug Reflash almost immediately when the 2006 trucks came out. Just thought I'd throw that in. Food for thought.

 

[trotorx2]

Yes that was done when I bought the truck. Truck starts and runs fine. I'm going to havee it looked at next week...been too busy.

 

[RI Chevy Silveradoman]

OK. Good luck and keep us posted.

 

[alli_gator]

I must be goin crazy, I answered you yesterday...I thought.

I have around 45,000 miles on the motor. I'm still getting the CEL but when I check it with my predator now it shows no codes found but I can turn off the CEL by clearing the codes. The light comes back on later though. I guess I need to go have it read with a better reader.

BTW which cyl. is #6?

Thanks

Cylinder is the 3rd cylinder back on the drivers side.:thumbsup:

 

[Joey D]

I just had to replace 2 as well, I did all of them as a precaution.

 

[trotorx2]

Sorry for the late reply. I talked to the dealer and was told there was a bulletin out to change them all so they replaced them under warrenty.

A little off topic...they also said there was a ECM upgrade available,does anyone know what it covers?

 

[KYshooter]

Does anyone know where I can find this bulletin or if there is somekind of document number? I just had to take my LBZ in for #8 glow plug. I requested they replace them all. They called back today and said they only did one because nothing was wrong with the others. Since I'm already paying the $100 deductible I'd really like to get them all done and not have to keep taking it back.

 

[BigDogYJ]

Document ID# 1802153
2006 Chevrolet Chevy K Silverado - 4WD

Subject:Diesel Engine Glow Plug Trouble Codes - keywords calibration circuit glowplug GPCM hard indicator LBZ LLY module multiple P064C P0671 P0672 P0673 P0674 P0675 P0676 P0677 P0678 program programming SES #PIP3586C - (03/28/2006)


Models:2006 Chevrolet Express, Kodiak, Silverado
2006 GMC Savanna, Sierra, TopKick
Equipped with the 6.6 (RPO - LBZ or LLY) Duramax Diesel Engine ​

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1802153&psdid=1233&evc=sm#ss1-1802153">Condition/Concern:

A vehicle may be brought into the dealer with the SES light on and multiple cylinder glow plug DTCs set. Multiple glow plug DTCs may be caused by internal opens in the glow plugs. There are two different descriptions for an internal open in a glow plug. A fast open glow plug is a plug with an internal open circuitry, but no visual damage to the tip of the plug. A slow open glow plug is a plug that has internal open circuitry, and the tip of the plug is missing or damaged.
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1802153&psdid=1233&evc=sm#ss2-1802153">Recommendation/Instructions:

Complete the current SI diagnostics for any symptoms or DTCs found. If the diagnostics for P0671-P0678 led to a glow plug resistance of more than 1 ohm, replace all of the glow plugs. If any of the glow plug tips are missing, the cylinder head must be removed. All debris needs to be removed from the cylinder. When the tip of the glow plug enters the cylinder, engine damage may occur. Make any engine mechanical repairs as needed.

1. <LI type=1>A loose battery feed connection at the starter, alternator, or the Glow Plug Control Module (GPCM) may induce glow plug concerns. When the starter, alternator, or GPCM battery feed circuit has a poor connection, the GPCM will sense a voltage fluctuation, and induce the GPCM to power up the glow plugs. Untimed GPCM cycling may cause glow plug concerns. Inspect the connections at the starter, alternator, and both ends of the battery feed cable to the GPCM. Connector C1 terminal 1 at the GPCM is a quick disconnect type of connector. Make sure terminal fit is clean and tight and the quick disconnect is seated properly. The source or main power feed location differs depending on the vehicle being serviced. On GMT800 C/K model trucks, the power feed stud is located in the Under Hood Bussed Electrical Center (UBEC). To access this power feed stud, the secondary UBEC cover has to be removed. On GMT610 "G" vans inspect the underhood junction block connection. On GMT560 4500/5500 trucks inspect the secondary fuse block connection. <LI type=1>There are other electrical scenarios that can induce glow plug concerns. If the glow plug system senses a certain electrical "noise" on the power feed, the glow plugs may also go open. This electrical "noise" may be induced by jump starting, disconnecting the batteries with the ignition in the ON position, or a battery charger being used during a module reprogramming event. <LI type=1>If the glowplug DTCs have set on a very low mileage vehicle (below 1000 miles) the glowplugs may have been damaged by the engine start up test conducted at the engine assembly plant. <LI type=1>Do not replace the GPCM for all 8 internal opened glow plugs. GPCMs have been returned and inspected with no problem found.
2. Complete all electrical circuit inspections and engine repairs as described above. After necessary repairs are completed, update the calibration in the GPCM. (See campaign 06522) Install the new GPCM software, and complete Fuel Injector Flow Rate Programming following SI procedures.

Note: Add-on remote starter or alarm kits must be removed before any glowplugs are replaced. Interruptions to normal starting procedures may induce glowplug concerns.
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". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

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© Copyright General Motors Corporation. All Rights Reserved. ​

Document ID# 1802153
2006 Chevrolet Chevy K Silverado - 4WD

 

[saratoga]

Now the stupid thing is throwing a code for a bad glow plug- P0676. I haven't had a chance to pull it out yet, but called a couple of dealers.

One has them in stock for $20 and change each. Probably going to pick one up tonight. The truck's still under warranty, but I have zero time to take it to the dealer right now. If the tip isn't broken off, I'm just going to change it out myself.