dtc code 380

[JF]

i own a 2001 2500hd duramax. service engine light appeared and i scanned it. i got the dtc of po380. i have 102,000 miles and i changed all eight of the glow plugs, one of them was brkoen when i took it out so i figured that this is why i was getting the code. i cleared the code and after 2 ignition cycles, it came back. i am looking in line of the glow plug relay because my scan tool is telling me that my glow plugs have no volts. there are 2 relays sitting side by side. anyone have any idea which relay it is or how to solve the problem?

[madmatt]

every p0380 I've seen was fixed w/ a glow plug controller. Thats the complete relay assembly. both relays and all the other connectors and posts included.

[JF]

the dealer only had a listing on one relay and not a controller. any idea what this costs?

[JF]

Replaced glow plugs (one broken),check engine light came back on. Replaced Glow Plug Controller, which came complete with relays, and problem solved. Truck runs better also. Just a note: the controller comes complete with 2 relays for less than the cost of buying 1 relay.

[madmatt]

Ain't that odd? I was amazed when I inadvertently told my parts guy I needed a glow plug relay when I meant a controller not knowing the relays were available seperatly then low and behold he handed me a single relay. I had put a dozen of these controllers on and never once had he mentioned a seperate listing for a relay.

[DmaxMaverick]

TTT for Mattb5150

[mattb5150]

On the 2002 Duramax with just over 101k miles no mods or boxes. Had fuel in oil, took it in to local GMC dealer and had all 8 injectors replaced. Now it has an intermittent SES light, only on after glow start, once warm and engine is shut off no more light. Took to Autozone today and scanned it, got the P0380 glow plug code.

Could this be from the dealer screwing something up? Or is it cheaper to go ahead and replace the controller and relays on my own? Anyone have the part number for the controller/relay bundle and a price?

Thanks,

Matt B.

[DmaxMaverick]

California model?? I can help with that. Check out This Thread (http://www.thedieselpageforums.com/tdpforum/showthread.php?t=9645). Been there. Done that. You may not have to replace the controller, or anything other than one glow plug. Run through the tests, and get back to us.

[mattb5150]

Yes Maverick it is a California model. I don't have a Predator or the manual but I do have a multimeter but am not that savvy with it.

I take from the thread you posted I would be best off checking the resistance of each plug by unplugging the connector at the controller. Can you describe the where the controller is to me and how I would go about checking the resistance of the plugs?

Thanks,
Matt

[DmaxMaverick]

No Problem.

Click on the Truck Stuff Pics link in my sig. Just happen to have a couple pic's of the top of the controller, and the 2 connectors near the rear. Each connector has 4 wires, one each for the plugs. They're even separated by bank, and number. Once you get the connector off, check each wire for continuity, with your ground probe grounded to chassis. I've seen several failed plugs, and every time, they fail open (infinite resistance, or no meter response). IMO, that would be as good as checking voltages with a scanner. Ultimately, if you have a problem with the connector trick, you can check each plug individually by disconnecting them at the plug. Just remove the nut and check the threaded stud sticking out. Your ohm meter should show nearly a dead short. A test light would work as well. If you find a bad one, they remove/replace just like spark plugs.

One other catch.....
If you find that all your plugs are good, you're not done. Check the intake heater, too. If it, or the controller fails, it'll show the same DTC. Checking the heater is the same as for the plugs. On a cool morning, there should be 12V at the heater for several seconds, and it will get hot enough to feel the heat on the intake plenum. The heater is located in front of the turbo, threaded into the cast aluminum pipe that goes into the intake manifold (last stop before the head), like a large spark plug with a threaded pole for the wire, held on by a nut. It's big...you won't miss it.

[jdevault]

I had a similar problem with my 02 DMax. Dealer replaced 8 injectors under extended warranty. Afterwards, I got a code indicating glo plug controller problems. Although I did not have this problem before the changeout, the dealer claimed that they did nothing to cause the problem. $350 later, at my expense, the problem was cleared with a new glo plug controller !!

[mattb5150]

Okay viewed the pictures and there looks like there are 3 plugs on the controller any hint as to which are the two that go to the plugs?

Matt B.

[DmaxMaverick]

Okay viewed the pictures and there looks like there are 3 plugs on the controller any hint as to which are the two that go to the plugs?

Matt B.
At the rear of the controller, it will be the 2 outboard connectors. Each will have 4 wires inline, and the wire colors will match the wires at the plugs. In the pic, it is the pink wires on the left, and the white/blue on the right.

[mattb5150]

Okay got it. Seventh one I checked, it's the white wire with the light green stripe, any idea which number cylinder that one is? Are the cylinders numbered the same as the 6.5. I don't see any markings on the max but can reference my old '93. Are all dmax glow plugs the same or is there a recommended type? Was thinking for one I would just go to NAPA, Autozone or Kragen rather than order one and have to wait.

Thanks,
Matt B.

[DmaxMaverick]

The cylinder numbers are opposite of the 6.5. Odd cylinders are on the passenger side, #1 is the forwardmost. The wire colors at the plugs should be the same as the connector. To ID the bad plug, test the plug connectors at the plug, the same as you did with the connector. The bad plug will be open, or infinite. Once you ID the bad plug, R&R it.

You can get new plugs at the dealership. Price won't be much more, if any, than Napa, etc. Be sure to get an OEM plug. I'm not too comfortable with the aftermarkets, yet. The GM part # is 97226202. www.gmpartsdirect.com shows them for $8.34 their price, and $13.93 GM list price. If you get them (get an extra!) from gmpd, the S/H charge may negate the price break on small items. If you can't get one locally in a short time, www.kennedydiesel.com has them at a competitive price (that's where I got mine). He can ship them to you quickly. In either case, don't get in a hurry. You aren't hurting anything with only one bad plug. The only drawback is the SES light won't go away until you replace it.

If all else fails, I have an extra I can send you. You can then replace it as they become available, or just mail me a check. I should be able to get it to you in 1 or 2 days postal. I'm located about 100 miles S/E of Fresno.

BTW
If you pull the fender liner on the side you need to replace the plug, you'll be able to R&R it very easily. The only one hidden is the #1. It's behind the intercooler pipe. If you have to remove that one, take the pipe loose at the top, and push it out of the way enough to get at the plug. I don't suggest taking it loose at the bottom. You will likely have a problem getting that connection to seal up, and it can blow off later under load.

[DmaxMaverick]

Matt

I opened the thread I created last year on this subject. Please reply with your results there, or here. This is all good info for an issue that will surely become more common as time passes.

[mattb5150]

Hi Mav,

I'll pick up a plug at the local dealer. I can trace the plug down as you described I just thought that you may know exactly which cylinder number I was describing (white/lt. green stripe) since you mentioned they were labeled somehow and that you may have a wiring diagram for the truck which I don't have.

Thanks,
Matt B.