Fault Code P0674 Cylinder 4 - Glow Plug, Circuit

sootwagen

Veteran Member
Joined
May 25, 2003
Location
Nowhere
TDI
None
Either a bad glow plug, or a bad connection between the glow plug and the glow plug harness. With 10K miles on it, make the dealer fix it under warranty...
 

DieselJeff

Veteran Member
Joined
Nov 16, 2003
Location
Nashua, NH
TDI
'10 Jetta 6MT & '11 Jetta DSG
I've had that happen to me twice in 2 years. Just reset it and allow your plugs to do their thing for a couple seconds before you fire it up. I attribute that code to being impatient which I am.
 

WillR

Veteran Member
Joined
Mar 2, 2001
Location
Honey Brook, PA
The ECM does some kind of test to the glow plugs, weather its current or resistance I am not sure. Being in a hurry will not affect this measurement. I have heard of a couple 05 PD's on here having the glow plugs changed out. Might have been a bad batch made it into the USA. Take it to the dealer and let them fix it.
 

Uncle_Dave

Veteran Member
Joined
May 1, 2003
Location
Boston MA
TDI
Jetta TDI Wagon A4 Silver
I also have P0674, using a CarChip. Thought I would be smart and pull different wires off the Glow Plugs. Always get P0674. Pull all the wires at once and still the same. The only thing that is consitant is that it take 30 seconds for the code to show up. I had P0671 and P0673 about two weeks ago, but then they went away. Have come back to bite me.
 

Uncle_Dave

Veteran Member
Joined
May 1, 2003
Location
Boston MA
TDI
Jetta TDI Wagon A4 Silver
Take off the connectors to the Glow Plugs, put some dielectric grease on them, and put them back on.


For the past few days I have been going over this engine looking for a cause for the P0673 that has been showing up. The check engine light has been coming on after about 30 seconds.

Went so far as to blow out the 20 Amp scale on my DVM.

I have been trying to run this to ground.


Later this month I have to make a drive to Ohio from Boston, and can't have the CEL on.


Late in the afternoon I made the decision to bite the bullit and buy a
new relay. Just can't find anything wrong. Pulled off the cover, to check the numbers off the relays.


What has been throwing me is that the CEL does not come on right away, and when it does, it is not concistant with the numbers it gives me.


When the problem showed up, I went over to Auto Zone, and they came up with the same number, but when I left the CEL had gone out and stayed out for about a month. Well if it can go out, it should be able to stay out.


I am using a CarChip to read the Codes. I have not had to work with these. It has provision to shut the CEL off. However the CEL is off when I start the car. Turns on later.


I just set the Chip to turn the CEL out, and it did, and the memory is cleared. Right now No Codes.


In the mean time I have been going over ideas to kept this from happening again.

I really would like this car to Last. With VW, and their mind set.

I would take all the electrical connectors and put some dielectric grease on all of them to keep the Road Salt, and water out of them.

Basicaly start to treat it like it is broken.


Don't ask about my oil plug being stripped out, or sitting on the side of the road for 2 1/2 hours because the Wheel had Froze to the axle.


This may sound sort of strange coming from me, however not that I have started to get my hands dirty, and fixing this TDI is starting to grow on me.

When you stop for fuel, ask if anyone has had probems.
 

JoeBleed

Veteran Member
Joined
Mar 29, 2005
Location
Macclesfield, NC, USA
TDI
Jetta, 2005 A4, Reflex Silver
It is a long shot, but try and pull the ECU connector and make sure the harnes connector and the plug on the ECU is good and clean. Since the ECU is what is measuring it, might as well make sure it can measure it corectly.

Just a wild guess, but it is free if you do the work yourself.
 

Uncle_Dave

Veteran Member
Joined
May 1, 2003
Location
Boston MA
TDI
Jetta TDI Wagon A4 Silver
Think I have been wrong with my ideas on the Glow Plug CEL. I went over to talk to the Guys at the local Dealership where I have been going to. I did not get much in the way of help.

One thing. There are not many VW TDIs on the road. I have a 2003 with 90k miles, so I am probably further down the road than most.

I have the Bentley Manual for the 2003. It tells me that I should see 6 amps through the Glow Plug. I measured over 20A and blew out the 15A fuse internal to my DVM.

I have been trying to check for specs on Glow Plugs from the different MFGs however I have not been able to get any site that will take questions. However it looks like there is a new Ceramic Glow Plug that is more efficient than the older ones. That these do take a lower Voltage, and Draw less Current. And my be pulse width modulated with a chopped DC voltage. Using a meter will read 6.5 volts or so. The Tip is reported to get very Hot Very Fast.

I would suspect that you just can't mix and match.

I am an old timer. I had a VW Rabbit. I had some minor problems, However, they were corrcted. What they were doing back then was to start to keep the local mechanic out of the engine. They were starting to use the Strech bolts. Torque them down and then go another 1/4 Turn or so. The service manager finally showed me a Service Bullitin where the Diesel still wanted the heads to be retourqued the old way, after 1000 miles after engine work, and a New Car as well.

Then there is the DexCool. But again, we are trying to keep people out of the engine.

There has been a lot of mis-understanding, and mixing and matching.

Putting 12 volts on a 7 volt Glow Plug will burn it out very quickly, but not right away.

How does the ECU measure a good Glow Plug? use a Shunt or a Hall device?

I have been known to make my oun Test equipment in the past. However it helps to know what you are looking for when you do this.

For example. Using a 12 Lamp to check the glow plug. If either type of glow plug is being tested by a Brake lite, the resistance of the GP will light the bulb pretty much to full brillyence. You need a better way to read the current.

Never said I can spell.

With the newer Ceramic GPs if they use a Pulse Width Scheme, you should be able to hear some sort of a tone, if you were to use a speaker and capacitor.

The local mechanic, what does he care? A GP is a GP.

BTW With my CEL, I have tried some NAPA Battery Post Cleaner on the Battery, Heavy metal Fuse links, and the GP Connectors them selves. And have been able to put the CEL out.

dhlawry@earthlink.net I do have kids in the Hot Zone, I have the blocker on tight. Glow Plugs will let you through.
 

cqpate

Well-known member
Joined
Feb 3, 2004
Location
fort worth
TDI
bug 2002(RIP), jetta 2006 silver, jetta 2006 blue
reset time?

i got p0647 cyl 4 recently and put in a bosch plug with engine light staying on after several days. back to autozone and they hit reset since i put in a new one. will the engine tell me again if it goes bad soon? why is cyl 4 not glow plug 4? makes for confusion.
daryl ft worth
 

Crispy_8V

Well-known member
Joined
Apr 26, 2005
Location
Mersyside, UK
TDI
Mk1/A1 Golf GTTDI, Mk4 GTDI & Corrado TDI
MK 5's have had a 3 with glow plug light, I've fixed all with glow plug no. 2!!
changed the plug & the cars never come back with warning light on!!
yet....!
 
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