Glow plugs 101 ***Ver. 2.0***

economicuskp said:

When starting my car, the glow plug indicator sometimes comes on (about one in ten times maybe) and otherwise does not. When it does not come on, the car obviously won't start.

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Sounds like a Relay 109 ("Main Power Relay") problem... the early ones are known to be intermittent... if you don't get any of the dashboard lights coming on, that's the problem... The VW part number is 1J0-906-381-A...
(Also comes as 130-906-381-A)

It's found above the clutch pedal, just in back (to the right) of the fuse panel...

Yuri.

ymz said:

if you don't get any of the dashboard lights coming on, that's the problem...

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I thought it was just the gp light. Is this different for different models?

Why Glow Plugs in Hot Weather?

This is probably a really dumb question, but here it goes...

Why are the glow plugs needed to start my '99 New Beetle given that it's 100 degrees F outside?

Thanks,

Ken

They aren't.

economicuskp said:

This is probably a really dumb question, but here it goes...

Why are the glow plugs needed to start my '99 New Beetle given that it's 100 degrees F outside?

Thanks,

Ken

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The light that goes on when you first turn the key is telling your that the ecu is checking circuits. It doesn't turn on the gps for starting over 40F or so.

If the light doesn't go on, usually the car won't start - not because of the gps, but because the ecu isn't getting power.

rdkern said:

I thought it was just the gp light. Is this different for different models?

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The other dash lights are coming on. Just the GP light is not coming on.

Haven't had the brake light switch recall work performed yet--will do that this weekend. Probably an outside chance that it will affect anything, but since some people apparently had a blinking GP light from that, thought I'd try.

I had the relay 109 replaced long ago (maybe back in 1999), but it sounds like it could be a candidate. The fact that it works sometimes but not others makes it seem almost like loose wiring somewhere.

Thanks for the help,

Ken

If the gp light is NOT coming on - coupled with a no-start - replace the 109. 99% chance on this one.

Will Try the 109...

Thanks Rdkern. Will give it a try.

Ken

2002 TDI getting engine code 10757

I have a 2002 TDI with the following problem:

Getting engine code 10757 for the number 3 plug
My mechanic has replaced the glow plug (#3 both times) twice in the last 6 months but I got this code again. My mechanic said to take it to VW because he could read the code. VW tells me that want to change the glow plug and the harness. They want to charge me 350.00 in labor for this.

Is this the best solution? Honestly I don't trust VW service and would rather go back to my mechanic and have him do this if this will finally fix this issue. I will be out 120.00 just for letting VW check the code but I really don't want to give them any more money if I don't have to.

Any help would be appreciated!

BTW as the VW CSR was on the phone also mentioned about 3000.00 in additional work that he suggested that I get done. I hate the hard sell on services.

Start at the beginning of this thread - read it. You will then decide what to do. by the way, if the ecu says #3 is bad, generally it's #2. Testing the gps, replacing bad ones, and cleaning the harness would be my suggestion.

dave ojeda said:

BTW as the VW CSR was on the phone also mentioned about 3000.00 in additional work that he suggested that I get done. I hate the hard sell on services.

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Why don't you contact UserID "MiksTDI" and take a short drive to Lake Villa... he's one of the TDI-Club "Gurus" who can definitely take better care of your car for far less money than you'd spend elsewhere...

As rdkern said, most likely your # 3 glow plug fault is with the glow plug in Cylinder # 2... and often the problem's not the plug but simply corrosion inside the harness... that can often be treated by something similar to DeOxit D5...

The timing belt on your car is rated at 80,000 miles... possibly what the service writer was talking about was the replacement of that critical bit... Again, I'd far prefer to see you have that taken care of by someone such as Matt Miks...
http://forums.tdiclub.com/member.php?u=8026

All the best,

Yuri.

dave ojeda said:

I have a 2002 TDI with the following problem:

Getting engine code 10757 for the number 3 plug
My mechanic has replaced the glow plug (#3 both times) twice in the last 6 months but I got this code again. My mechanic said to take it to VW because he could read the code. VW tells me that want to change the glow plug and the harness. They want to charge me 350.00 in labor for this.

Is this the best solution? Honestly I don't trust VW service and would rather go back to my mechanic and have him do this if this will finally fix this issue. I will be out 120.00 just for letting VW check the code but I really don't want to give them any more money if I don't have to.

Any help would be appreciated!

BTW as the VW CSR was on the phone also mentioned about 3000.00 in additional work that he suggested that I get done. I hate the hard sell on services.

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If you have the latter 4-wire glow plug harness--- you might want to take ymz reccomendations for quick fixes.

The latter harness is a PITA to get to, because you will be ripping out a lot of stuff to separate the wiring & to get to the connect point at the firewall. Taking your time to do it carefully and reinstall (including putting electrical tape on the parts you cut out) should be about 2 hours.

Oops...bad battery...

economicuskp said:

Hi,

I have a '99 New Beetle. When starting my car, the glow plug indicator sometimes comes on (about one in ten times maybe) and otherwise does not. When it does not come on, the car obviously won't start.

I just finished replacing the glow plugs and wiring harness, but have the same problem.

Any suggestions? (Wiring connection to fuse box near battery, metal fuses, glow plug relay, coolant temperature sensor, or none of the above?)

Thanks,

Ken

Click to expand...

Well, I think I found the problem. Car turned over a couple of times but wouldn't start the other day upon coming out of the Barnes and Noble. Replaced the battery (which had 5.5 years on it) and the mysterious glow plug light problem went away, along with a couple of other little things. Think I'll replace the 109 relay anyway since I definitely have a black one that dates back to late '99 or early '00.


Best wishes,

Ken

Small residual voltage in glow plug circuit

The reason you will see a small voltage on your DVM (digital voltmeter) is because electronic circuits don't completley shup off like a switch or relay does. A 'forward bias' is always present when the circuit is active. You could refer to it as leakage if you wish. The typical forward bias used to be .7 volts with old transistors but with better electronics this has surely been reduced.
Just FYI - sometimes these useless tidbits make for a more complete picture.
Enjoy
Tom

So I have a new 2005 TDI and on the control panel it says Emissions Workshop. I took it to the dealership and they tested it and said the glowplugs are bad. They want 590 bux to change them out, then 95 for the diagnosis.

Is there a way I can just bring my car home and check out the plugs on my own and see which one is bad as was listed in page 1? I hate to give up $700 if just 1 or 2 glowplugs are bad. I dont mind tearing stuff apart to fix it as I work on cars often.

Smoke, is your car still under warranty?

You can get new glow plugs online cheaper than at the dealer and they are almost as easy to change as spark plugs. You glow plugs are very fragile, so care must be taken, otherwise, it's very easy.

Accept that you will need to pay for the diagnosis but don't let themjack you around by paying that much money for them to change the Glow plugs.

Find someone local to you with VAGCOM and get it taken care of much cheaper.

As Whitedog said... the glow plugs on the PD engines are quite fragile (Ceramic)... They're different from the ones used on the 2003-and-older TDI's, so make sure you buy the correct replacement items !!

That said, often the problem stems from corrosion inside the glow plug harness and not from the glow plugs themselves... do a bit of reading around here... you should check the resistance of each glow plug (while still in the cylinder head) with a digital multimeter... that may give you a rough idea of whether you have a bad one... (not a foolproof test, but can't hurt)...

As far as the possibility of them breaking off during removal: a definite possibility in the PD engines, but chances are that could have happened at the dealership as well, so it's a crapshoot...

Good luck,

Yuri.

whitedog said:

Smoke, is your car still under warranty?

You can get new glow plugs online cheaper than at the dealer and they are almost as easy to change as spark plugs. You glow plugs are very fragile, so care must be taken, otherwise, it's very easy.

Accept that you will need to pay for the diagnosis but don't let themjack you around by paying that much money for them to change the Glow plugs.

Find someone local to you with VAGCOM and get it taken care of much cheaper.

Click to expand...

Yes,
I bought the extended warranty for 100K bumper to bumper, but they tell me this isnt a warranty item. Normal Wair item they say...

What is VAGCOM?

Question about 16764 code

Hi everybody! Since I'm new to this forum I wish to thank the guys behind this great site and everyone also in the forums.

Here's my problem: MIL ligth gets on after starting and driving the car, as soon as the RPM rise above idle. Which I don't understand because the heating process is done at this point.

Is it possible that the relay coil "sticks" or is it solid state type?

Thanks for your help!

I found a place online that says:

"Replace your failed factory glowplugs with our premium dual coil glow plugs for all 1.9L TDI diesels. They are the cylinder heating glowplugs and will fit all models (Jetta, Passat, New Beetle, Golf, etc.) with the 1.9L TDI. They will not fit the 1.9L non-TDI diesel."


So these will work in my new 05 Jetta??

also found these:

Thank you for the instructions!

Had a P0673 on my OBD II code reader. I Decided to change all 4 glow plugs instead of changing just number 3. Prior to reconnecting the glow plug harness, I sprayed CRC electronic cleaner into it each terminal to flush out any corrosion. Snapped all connectors tightly and no more smoke when starting, engine seems to run smoother too.

Thank you to all who posted great information.

Thanks!

The information you put up, saved me a lot of time and money! Thanks!

EZ Relay Check

Instead of disconnecting the coolant temp sensor and dancing around the front of the car to test if the harness is energized, I just wait for a moderately cool morning (most mornings here) and let the glow plug light run itself out. If the car starts smooth, I can tell the plugs were juiced. Otherwise, check relay. My eco-dies has had some annoying plug relay probs...not in the TDI yet.

To see what a TDI starts like without glow plug priming, same conditions, just start immediately without waiting for the plug light. TDI's will start in anything but severe winter weather, but they'll choke a bit. My eco-diesel must run the plugs anything under 15 C.

My TDI spent 30K miles in Hawaii and had some wicked harness oxidation on the connectors. Perhaps it was the humid ocean environ.

Solder on GP terminals

I wrote in a post (6-Aug-2007) that I had melted solder onto the terminals (GP tips),
to try and keep the intermittent GP fault from appearing. It's been six weeks now, and
I have had no problems (no MIL, no fault codes). Prior to that (using DeOxIt, squeezing,
scraping contacts, etc.) I was only able to make the problem go away for a few days.
So, I believe that there may be some benefit to be had in this sort of technique. Larry C

capable Deoxit substitution

FYI....

CRC makes an electrical/electronics contact cleaner (QD series for quick dry time) that remedied my GP DTC issues. Just in case you cant get the Deoxit product

http://www.crcindustries.com/ei/content/prod_detail.aspx?PN=02130&S=Y

cylinder numbering

I Have read that the cylinder numbering is a bit wonky? ARe they numbered 1,2,3,4 left to right or the other way. Working on glow plug replacement after cleaning them with steel wool and still having #4 glow plug come up as source of problem

karibee said:

I Have read that the cylinder numbering is a bit wonky? ARe they numbered 1,2,3,4 left to right or the other way. Working on glow plug replacement after cleaning them with steel wool and still having #4 glow plug come up as source of problem

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OK, so you cleaned them with steel wool. Did you clean the harness as suggested here? Have you checked resistance of each glow plug?

karibee said:

I Have read that the cylinder numbering is a bit wonky? ARe they numbered 1,2,3,4 left to right or the other way

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Yes...

All of the earlier 4-wire-harness ALH motors (2002 and most 2003's) had the glow plugs numbered in reverse order to that of the cylinders. (Cyl.1 is next to the timing belt)

We've heard rumors that on some of the later 2003's they changed that so that they're numbered the same as the cylinders...

If you're not sure which is the case with yours, disconnect one of the glow plugs (# 1, for instance), look for the CEL, and read the code...

In any case, a good scrubbing of the contact areas inside the harness, mechanical as well as chemical (DeOxit D5), often works wonders...

Yuri.

Hi guys,

I'm looking for some opinions/help about my 2005 Jetta TDI Wagon. It's at just under 80,000km (the warranty deadline) and it's on its 3rd set of "defective" plugs from the dealer. I've had the engine light come on 3 times in the past 2 months, and now have had the plugs, wire harness AND plug module replaced. Is this symptomatic of a much larger issue? Incompetent mechanics? I have a hard time believing that glow plugs should last one fifth of what a spark plug does (my spark plugs lasted over 100,000km in my buick until I replaced them myself).

Overall, my TDI has had over $10,000 in repairs. I'm looking at either selling it (which I would hate, because I've loved this car like a family member) or continuing to have difficulties. As soon as it's out from warranty I'm definitely going to go through the process above to test the plugs myself - in fact I'd like to do 100% of the maintenance myself so I know exactly who to blame if things go amiss )

Any thoughts? Any help is greatly appreciated.. I don't trust the dealer as far as I can throw them.

Check to find out if they put in the correct glow plugs. The GPs from an earlier car will fit, but not work.