Newbie needs code help P0684

spdowell

New member
Joined
Mar 17, 2009
Location
Seattle
TDI
2003 Jetta
Same Problem..

I received the same fault code (P0684). I cleared the code to see if it would happen again and it did. I had replaced one of the glow plugs before and I thought it would be something like that.

I parked for the night after my drive, and when I came back the next morning the battery was completely dead (multimeter read 0.0).

I recharged the battery, and when I began driving I smelled a burning smell. After seeing this post, I remembered the cabin air filter was also in the plenum so I checked that relay. Sure enough, it was melted. I uploaded pictures into my profile.

Question is, do I replace the relay or the relay & harness? Also, could this have caused my battery to die, and if I replace the relay will that solve the root cause of the problem?
 

jcrews

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It should be safe to replace the relay. Just make sure none of the glow plugs are short circuits, and you read open to ground for each harness terminal.
 

myselfnjit

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May 13, 2008
Location
Owego
TDI
2003 Jetta Wagon
Just to be safe I am replacing the relay and the harness. I still cant find the part number for that relay connector or better yet the rubber seal though...
 

jcrews

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038973721B 11-pin flat contact housing $9

Part # verified

My apologies for posting some wrong information earlier - version A is the application up to (and not including) 2004 production for the relay. Here it is again: 038907281A
 
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myselfnjit

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May 13, 2008
Location
Owego
TDI
2003 Jetta Wagon
I replaced the relay and the harness. Turns out it was the relay after all but I replaced the harness too as I had bought it already and the old one was falling apart.

Glow plugs work now so I cleared the CEL and well see how it goes!!!

Thanks everyone
 

spdowell

New member
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Mar 17, 2009
Location
Seattle
TDI
2003 Jetta
Does anyone know the trick of removing the pins from the glow plug housing? I have tried the paper clip and bobby pin but can't seem to figure it out. My housing was melted from the relay so I bought a new one and need to replace it.

Additionally, will the car drive fine without the glow plug relay?

Thanks
 

jcrews

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I think you can get a release tool from Carquest. It looks like a crazy octagon thing with DURITE 0-703-99 written on it.

There is probably a secondary release block (violet) you need to slide over. There's typically a catch that you spread carefully with a screwdriver, and the lock moves over slightly. Then, you use the release tool to extract the pins. I was able to use a small paperclip bent up on several connectors, especially with the bigger contacts. You just shove it in so the legs compress little spring catches on the pins, then they slide out the back. Don't try to pretension the wires, or the catches might get stuck. It's tricky but once you get it, it's easy.
 

Louis_TDI

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Joined
Mar 28, 2008
Location
Gatineau QC
TDI
2003 Golf Gls
spdowell said:
Does anyone know the trick of removing the pins from the glow plug housing? I have tried the paper clip and bobby pin but can't seem to figure it out. My housing was melted from the relay so I bought a new one and need to replace it.

Additionally, will the car drive fine without the glow plug relay?

Thanks

You can still drive the car with the Gp not working you might have a hard time stating it if it's really cold out. the gp only stayon for a sort wille when you start the car.
 

JB05

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Golf,2005,anthracite blue
A search for part# 281 003 023 has led me to this thread regarding GP relays. This is the same number I see on a relay under the rain tray on my 2005 Golf PD. In post 18 it is stated that his GP relay, with the same part number, also has a 038 907 281 A on the reverse side. I was under the impression that the BEW had 038 907 281 C, and the A suffix was for the ALH. At this time I don't know what is on the reverse side of the module/relay on my 05, but it would seem to me that it should read with the A suffix. The wiring diagram # 83/3 shows a 9 pin module for my BEW.
WD 32/3 shows a 8 pin relay, J52 for the ALH. Can anybody help to clear up this confusion? A visual check with a small telescopic mirror through the louvers reveals that my BEW does in fact have the A suffix printed on the underside of this module. Now I'm even more confused. It appears that my PD should have the C suffix. Anyone care to comment? http://forums.tdiclub.com/showthread.php?t=128147&page=2&highlight=038+907+281+A
 
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sbernardin

Member
Joined
Apr 8, 2006
P0684 Glow Plug Controller

My 2004 wagon with 93k miles had a recurring P0684 code for the last few months, which has to do with communication between the glow plug controller and the electronic control module (ECM). I poured over the archives and threads on this website and others looking for answers as to the cause. The actual code explaination is your clue to the problem, has nothing to do with the glow plugs themselves or the harness (there are codes for this type of failure). I ordered the correct module for BEW from Amazon.com with the -C suffix and installed it this weekend, success! Symptoms for the glow plug controller failure on my car were hard starting in cool weather, increased smoke on start-up, rough initial idle and decreased fuel economy. By the way, there are no user servicable parts in the controller. There are a lot of "shade tree" mechanics and good intentioned folks contributing to this site but, as the saying goes, buyer beware!
 

JB05

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sbernardin, what is the part # on your original relay/module? Does it have the A or the C suffix?
 

sbernardin

Member
Joined
Apr 8, 2006
"C" suffix. A great place for information regarding the proper parts for your vehicle is your local VW dealer's parts department. Be prepared to give them your VIN# as there are many variations and revisions to parts that would otherwise be common to several years. By the way, the glow plugs stay on until the engine is up to operating temperature to help with emissions control. There is a lot of good troubleshooting information out there (Bentley Repair Manual for one) but there is also a lot of educated? guessing which I term "shotgunning". Like I said before, there is a lot of good data on this website and others, the trick is in doing your research and piecing together the "story" as it relates to your particular problem. Reading the "Official" manuals is a great place to start to get your problem solved. Also, as I mentioned earlier, the VW dealer can be helpful as well (they can check on sales volume of individual components such as glow plug controllers, giving you valuable insight for your troubleshooting). I always wondered why I had to learn how to solve those "word" problems way back in high school math....pay attention to details, oh, ok, I get it!
 

JB05

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According to the link I posted above, my BEW should have the C suffix, but again I do have the A suffix. Where does the pulse width 7 volts originate; is it in the ECU or the GP module/relay? I've searched for this answer both here and else where.
 

sbernardin

Member
Joined
Apr 8, 2006
I would call a VW Parts Department and verify the part number for your particular VIN#. Chances are your are correct in your assumption, but you'll sleep better at night knowing for sure. As for the "A" suffix in your car, if your are not the original owner but the car was serviced by VW, you can call the Service Department of the dealer the car was taken to and ask them to print out the service records for your vehicle. These include everything that was repaired or replaced and are a great tool. Of course, you will need to know where the service was performed. It should be in your glove box documentation as the dealer would stamp the service booklet each time the car was taken in.

Removal of the glow plug controller:

1. Remove the plastic caps on the wiper arms where they attach to the shafts (I used a small screw driver to work them off carefully).
2. Remove the 13mm nuts which hold the arms on (hold the arm as you do this for back-up so you don't twist the shaft).
3. You will need a small puller (another post recommended using a battery terminal puller, probably get one at a parts store) to lift the arms off the shafts. Keep the puller centered over the end of the shaft so you don't damage the threads. (I would'nt try any other method as these are on really tight, you will see when you use a puller!)
4. Set the arms aside and remove the black plastic wiper cover by first removing the pollen/cabin air filter cover on the left side, should be 3 or 4 phillips screws to remove.
5. Remove the rubber weather strip along the leading edge (engine compartment side) of the plastic cover by simply pulling up on it from one side to the other (this is the part the hood rests on when shut).
6. Next, work the plastic cover off, I started on the passenger side by first lifting the plastic at the base of the windshield near the hood hinge and at the same time lifting from the area above the pollen filter (reached inside the area with my "gloved" hand (protect your hands!)). At the base of the windshield, I used the plastic coated handle of a 6" crescent wrench (all I had) to establish a gap and fulcrum point being very careful not to apply excessive pressure to the glass!!!. Once the cover starts to separate from it's mounting it comes off easily (it is pressed on to a knife edge mount).
7. Next, remove the 10mm nut holding the controller down and disconnect wiring plug (press down on the tab and pull the controller away from the connector at the same time).
8. Installation is reverse of above.

Hope this helps!
 

JB05

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sb, thanx for the how-to. I am the original owner, but I was just curious why my GP module/controller is different than yours since we both have BEW's. There is no problem with my car, and the service records I have do not indicate that this module had ever been changed. I now wonder what the difference is between the A and C modules. I know, I should drive more and worry less.
Cheers, JB
 

sbernardin

Member
Joined
Apr 8, 2006
In checking with VW parts, the "A" suffix on your '05 Golf is a valid part number and is not interchangeable with the "C" suffix in my '04 (although other '04's use the "A"). They were not sure why the difference, but it probably has to do with the emissions controls, where the vehicle was manufactured, the geographical area the vehicle was sold in to (North or South), etc. Bottom line, stick with the original parts when you need to replace components.
 

jcrews

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A,C both are attached to the same ECM. They look interchangeable.

Both say ALH,BEW in the comment.

Part A says to read TSB 23-05-04, which I can't find. A dealership might have a copy on file.

IDparts sells part C for both applications.

The ECM sends either a message or drives (ST?) a line with a duty cycle. The directed duty cycle controls the average output voltage.
 

sbernardin

Member
Joined
Apr 8, 2006
TSB information for '05 Golf, reference 230504;

Technical Service Bulletins for the VOLKSWAGEN GOLF 2005 - 061000 ENGINE AND ENGINE COOLING - ENGINE

Make : VOLKSWAGEN Model : GOLF Year : 2005 Service Bulletin Number: 230501 Replacement Service Bulletin Number: 230504 NHTSA Campaign ID Number : 10012760 Date of Bulletin: 07/01/2005 Date Added to Database: 03/14/2005Component: 061000 ENGINE AND ENGINE COOLING:ENGINE Summary: RUNS ROUGH ON INITIAL START AT TEMPERATURES BELOW -7 DEGREES C (20 DEGREES F). *TT UPDATE. *TT UPDATE. *TT

I would go with a dealer recommended part before considering a "generic" replacement.
 

JB05

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This thread may answer jcrew's question and mine as to the A vs. C suffix on the GP controller. http://forums.tdiclub.com/showthread.php?t=100969&highlight=TSB+23-05-04 What I don't understand is why my DVM only reads 5v @ the GP harness. My controller has the A suffix, and the label on my ECU reads 038 906 016, the older software part no. It also has a 9116 sw version, which according to the steel GP TSB(01-08-33), is also the older version for the ceramic GP's. When I figure out how to use my new hand held oscilloscope, I will take another voltage measurement at the GP harness to see if that makes a difference due to the pulse width modulated signal from the ECU.
 
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