Code P0671 - Bad Glow Plug?

SKM348

Well-known member
Joined
May 29, 2004
Location
Tennessee
TDI
Golf-GLS, 2003, White
My check engine light came on today for the 1st time. Autozone read the code: P0671 - 'Glow Plug / Heater Cylinder #1. Does this mean I just have a bad glow plug? If so, is it easy to replace and where should I get the part etc. My car has 52k miles on it. Pls tell me what I need to do. Thanks!
 

ymz

Top Post Dawg
Joined
May 12, 2003
Location
Between Toronto & Montreal
TDI
2003 Jetta TDI Wagon, 2003 Jetta TDI Wagon
Yup, WingNut's "How-To"s are priceless!!!

I'm not sure if the following is included, so I'll just paste in my usual boilerplate:

On your car, the computer "counts" the glow plugs in reverse order... so your "problem" GP is really # 4 - the one closest to the driver's side...

That said, the problem is quite likely corrosion inside the harness... needs a good scrubbing with a Q-Tip (minus most of the cotton) and an eletrical parts cleaner or anti-oxidant such as DeOxit D5... may need to be done several times, followed by a clearing of the CEL with either a Vag-Com or a generic OBD scanner...

Yuri.

PS: as for buying new GP's: www.tdiparts.com was having a special recently... if Danix still has stock, it was something on the order of 4 GP's for $60, shipped...
 

SKM348

Well-known member
Joined
May 29, 2004
Location
Tennessee
TDI
Golf-GLS, 2003, White
YMZ-thanks
I just tested the plugs w/the OHM meter per WingNuts suggestion and it was the glow plug on the far right, #4 as you pointed out not #1 as the code said. There is a NAPA store here that carries Bosch for $22 each. Are they ok to use? I'm going to buy only one since the others tested good.
 

SKM348

Well-known member
Joined
May 29, 2004
Location
Tennessee
TDI
Golf-GLS, 2003, White
Yuri - one more question. You mentioned 'clearing of the code'. When I replace the bad plug, shouldn't the check engine light and code go away?
 

ymz

Top Post Dawg
Joined
May 12, 2003
Location
Between Toronto & Montreal
TDI
2003 Jetta TDI Wagon, 2003 Jetta TDI Wagon
Bosch and Beru glow plugs are what VW uses... I would still go for the TDI-Parts special, as you never know when you'll need to replace the rest, but... your choice... (also, some cars like to have fairly closely-matched glow plugs, meaning they don't like to mix the 2 brands, but most people have not had a problem...)

You'll need to have the code cleared by either a generic OBD scanner (AutoZone may clear it for you) or a Vag-Com... some error codes go away by themselves after a while... glow plug ones do not...)

Yuri.
 

2002MK4

Veteran Member
Joined
Jan 24, 2011
Location
Scarborough
TDI
2002, 2003 Jetta TDI
Yup, WingNut's "How-To"s are priceless!!!
I'm not sure if the following is included, so I'll just paste in my usual boilerplate:
On your car, the computer "counts" the glow plugs in reverse order... so your "problem" GP is really # 4 - the one closest to the driver's side...
That said, the problem is quite likely corrosion inside the harness... needs a good scrubbing with a Q-Tip (minus most of the cotton) and an eletrical parts cleaner or anti-oxidant such as DeOxit D5... may need to be done several times, followed by a clearing of the CEL with either a Vag-Com or a generic OBD scanner...
Yuri.
PS: as for buying new GP's: www.tdiparts.com was having a special recently... if Danix still has stock, it was something on the order of 4 GP's for $60, shipped...
My car threw out the p0671 about a month ago. Now I am up to a p0671, p0672 AND P0673.

Did [most] of the Wingnut process with my digital multimeter. Plugs are fine.

So is this the car gods telling me my wiring harness is slowly turning into Toast and given the new codes can cleaning my wiring harness help or do I need a brand new one???
 

JB05

Top Post Dawg
Joined
Oct 20, 2005
Location
Il.USA
TDI
Golf,2005,anthracite blue
I would try spraying the inside of the harness with some electrical contact cleaner. This always works for me, but my harness is not as old as yours.
 

2002MK4

Veteran Member
Joined
Jan 24, 2011
Location
Scarborough
TDI
2002, 2003 Jetta TDI
I would try spraying the inside of the harness with some electrical contact cleaner. This always works for me, but my harness is not as old as yours.
When you say spraying the inside, do you mean removing the harness from the car and disassembling it and then giving it a good dose of Deoxit?
 

fouillard13

Veteran Member
Joined
Oct 8, 2012
Location
Pincher Creek, AB
TDI
03 Jetta TDI Standard
I’m getting this code now too and just replaced my glow plugs last year with the proper ones from idparts. Wonder if it’s my harness going too.
 

Curious Chris

Top Post Dawg
Joined
Jun 11, 2001
Location
Pineview GA
TDI
Jetta Wagon 2003 RIP Rockford IL
On my dearly departed 2002 (RIP 305,000) I changed the glow plugs about 3 times and the harness once. I always replace all 4 as they are all on the same amount of time and in Reliability theory there is the wear out point where 63% of the products fail.
 

fouillard13

Veteran Member
Joined
Oct 8, 2012
Location
Pincher Creek, AB
TDI
03 Jetta TDI Standard
got that code again today. happened on the first cold day of winter it seems. these are all the new updated glos plugs that are under a year old.


what could it be?
 

Tdijarhead

Top Post Dawg
Joined
Nov 10, 2013
Location
Lawrenceville PA
TDI
2003 TDI Jetta Daughters Car, 2001 TDI Beetle, Wife’s car, 2005 Golf TDI Mine, all 5 spds
Is the code just for one cylinder? If so get a small piece of aluminum foil, roll it into kind of a spit ball size and push it up into the glow plug harness connector that you’re getting the code on.

I just put together a Jetta for my daughter and the number one cylinder kept throwing a code. Even with a new glow plug. I had read about this trick a year or so ago on this forum and never had to try it before now, and it seems to have worked. Day three no code.
 

Genesis

Top Post Dawg
Joined
Feb 26, 2003
Location
Sevier County TN
TDI
'03 Jetta Wagon
I got these on and off for a while on my '03 a number of years back. I did the crimp trick, the foil trick, cleaning the top (connector) on the plug, etc. Plugs would test good, but the code would come from time to time.

I finally got tired of it and changed the harness. Since then I've had two glowplug codes pop up (been about 5 years now) and both were legitimately burned-out glowplugs. Replaced the bad plug, code goes away.
 

tdidieselbobny

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Joined
Apr 4, 2005
Location
Stafford,NY (WNY)
TDI
'03 Galactic Blue Jetta TDI, '15 Silk Blue Golf Sportwagen TDI
This actually popped up last week on me. Is the #1 cylinder closest to timing belt? It's a new oem harness back in the spring a little bit after I bought it, all plugs tested good IIRC, I did have new ones but didn't want to eff anything up, as I'm not sure if they're originals or not-pretty sure the harness was, and that was at around 420k....
 

Nero Morg

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Joined
Oct 19, 2017
Location
OR
TDI
2014 A6 TDI, 2001 Jetta TDI, 2014 Passat TDI
Yes #1 is closest to the timing belt.
 

WolfgangVW

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Joined
Oct 16, 2011
Location
Alberta, Canada
TDI
2003 Jetta TDI - Manual
OP listen to all the advice here and check out the how to. If you indeed decide to replace the plug(s) read up on that too. Long story short years ago i had a GP fault, decided to replace all 4 and when i went to remove one it was tight then broke free then just spun in the head it had been stripped or over torqued before , doesn't have blowby my mechanic even checked it etc, and it wasn't even the bad plug. Anyway a few years later it finally faulted. Now i'm stuck with 3 working GP's not wanting to risk messing with it or getting into heli coil stuff. Just have to live with plugging in in cold temps and the CEL (which drives me nuts!) But had i researched more perhaps i wouldn't be in this scenario. Good luck!!
 

Diesel2005Golf

Active member
Joined
Aug 17, 2010
Location
Ottawa, ON, Canada
TDI
2003 Golf
My check engine light came on today for the 1st time. Autozone read the code: P0671 - 'Glow Plug / Heater Cylinder #1. Does this mean I just have a bad glow plug? If so, is it easy to replace and where should I get the part etc. My car has 52k miles on it. Pls tell me what I need to do. Thanks!
Yes it is easy to replace however I have found the position codes to be inaccurate for this. Stick an ohm meter on each glow plug before removing to find the one that is not working. You can get a glow plug at any auto parts store or dealer.

Be very careful of over torquing. See above post.

You will need a 10mm deep socket with long extender to reach.


Do not replace all 4 at same time. Just the one that is bad.
 
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Mac27041

New member
Joined
Jul 30, 2016
Location
Nc
TDI
2006 Jetta tdi
2006 vw jetta 1.9 tdi just came on ,
p0671 circuit emissions work shop
Any help thank you
 

SMSTDI

Member
Joined
Dec 14, 2020
Location
Richmond, VA
TDI
2012 Passat TDI SEL
Hello,

I have 2012 Passat SEL with 49K miles. I have purchased this at 37K miles from dealer after they completed all the recall work.

Recently I see the engine check light. Upon checking with OBD reader I see the codes P0671, P0672, P0673 and P0674. Is it possible that all 4 glow plugs are bad at the same time? Next possibility is the accessory relay 03L-907-282-B, this is about $80-90. A lot of forums have a discussion on the wiring harness, can someone explain what is the check and/or solution to that issue?

Any other recommendations? Thank You
 

Midwesthick

Veteran Member
Joined
Oct 26, 2011
Location
Denver
TDI
A3, GSW, 02-Golf
I had this code 2 weeks ago(P0671). Messed with my harness by removing it and making sure it was sealed properly to my GP’s. It worked for a day.

Code came back, I spent $40 on IDParts for new Bosch plugs, installed them, and now it’s gone again.
 

SMSTDI

Member
Joined
Dec 14, 2020
Location
Richmond, VA
TDI
2012 Passat TDI SEL
I had this code 2 weeks ago(P0671). Messed with my harness by removing it and making sure it was sealed properly to my GP’s. It worked for a day.

Code came back, I spent $40 on IDParts for new Bosch plugs, installed them, and now it’s gone again.
Thank you for the reply. I was just debating on whether to change the glow plugs or the relay first?
 

Midwesthick

Veteran Member
Joined
Oct 26, 2011
Location
Denver
TDI
A3, GSW, 02-Golf
Thank you for the reply. I was just debating on whether to change the glow plugs or the relay first?
Totally fair. I changed the GP’s and my CEL went straight away. You could do both just to save time when purchasing online. Can’t be too expensive to pick up the relay as well.
 

Blacktree

Veteran Member
Joined
Sep 9, 2015
Location
Central FL
TDI
'02 Jetta 5-spd
Yes #1 is closest to the timing belt.
The glow plugs are numbered backwards. Yes, cylinder #1 is closest to the belt. But glow plug #1 is closest to the gearbox. Doesn't make sense, but that's how they did it.

Also as mentioned above, it's a good idea to test the glow plugs with a multimeter*, to see if the glow plug is actually bad. The glow plug is just a resistor, so you can check the Ohms. Infinite resistance (or a really high number) means the glow plug is toast. But if the resistance is low, then the glow plug is OK, and there's an issue with the wiring harness.

* You can test it by touching one of the multimeter probes to the tip of the glow plug (where the harness attaches), and touch the other probe to the cylinder head. Polarity doesn't matter. Electricity will flow either way.
 
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SMSTDI

Member
Joined
Dec 14, 2020
Location
Richmond, VA
TDI
2012 Passat TDI SEL
The glow plugs are numbered backwards. Yes, cylinder #1 is closest to the belt. But glow plug #1 is closest to the gearbox. Doesn't make sense, but that's how they did it.

Also as mentioned above, it's a good idea to test the glow plugs with a multimeter*, so see if the glow plug is actually bad. The glow plug is just a resistor, so you can check the Ohms. Infinite resistance (or a really high number) means the glow plug is toast. But if the resistance is low, then the glow plug is OK, and there's an issue with the wiring harness.

* You can test it by touching one of the multimeter probes to the tip of the glow plug (where the harness attaches), and touch the other probe to the cylinder head. Polarity doesn't matter. Electricity will flow either way.
Thank you - I believe instead of start spending money, the best good start would be to do some testing.

Something that I should have mentioned with original post: The car is driving normal, have the same power, acceleration as before and there are no issues except for the "Engine Check" light.

I'll post here the results of my tests.
 

Nero Morg

Top Post Dawg
Joined
Oct 19, 2017
Location
OR
TDI
2014 A6 TDI, 2001 Jetta TDI, 2014 Passat TDI
Another lazier way of testing glow plugs is use a test light. Connect to battery + and then touch each glow plug terminal. If it doesn't light up, glow plug is bad. Use that trick on my Ford.
 

wonneber

Top Post Dawg
Joined
Oct 12, 2011
Location
Monroe, NY, USA
TDI
2014 Jetta Sportwagon,2003 Jetta 261K Sold but not forgotten
I used the test light also.
It's a quick easy test.

I also used a clamp on amp meter to check the current through the GP.

I went through the same CEL issue after my 03 JSW was out of warranty.
Found out back then there was an updated GP harness, as well as 'quick start' plugs and controller relay.
Installed both, never had another problem.
 
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