Glo Plug Issue - Advice needed

Hi,
I have a 2000 Beetle TDI (34,000 Miles) with the following problem"

Fault Code 16764 Gloplug/Heater Circut (Q6) Malfunction 35-10 intermittent.

The dealer told me I have one bad gloplug plus two with low resistance.

Cost per glowplug - $48.00
Labor to replace all three - $281.00

Total cost $425.00 (ouch!)

First off, what would cause LOW resistance on a gloplug

This is the first non-warranty work this car has needed. I would prefer to change out the plugs myself. How difficult is it to access the plugs? Does it justify $281.00 in labor costs?

Thanks,
Glenn

Glo Plug Issue - Advise need

Glow plugs come out with a 10mm deep well socket.
Take them out and clean with diesel additive or fuel and put back in and see if light goes out after a little driving or else get a friend with a VAG, also get some dialytic grease from parts store and put some on each connection. I would not pay to have them installed, it's like changing out a air filter as far as difficulty goes.
Anyway, try that first, it's less than $5 and may fix problem. (the plugs are often sooted up)

Glo Plug Issue - Advise need

Labor to replace all three - $281.00

Click to expand...

Holy SHEIT!!
I just looked at that!!
They must have a helluva time pulling that cover off, as that's about the only thing in the way, there's a fuel line that make's it tight but a Universal (not really needed) get's around that if someone has a problem.

This job take's all of 15 minutes to do, with breaks for soda,beer,coffee,sex, etcetera...

WOW

Glo Plug Issue - Advise need

Hopefully, you got dinner and flowers for that...

3 hours labor @ $80 to change 3 $25 glowplugs. Take 2 1/2 hours to work on someone elses' car.

Glo Plug Issue - Advise need

Hopefully, you got dinner and flowers for that...

Click to expand...

No, I haven't had the work done by the dealership. So no dinner and flowers for me

Looks like I'll be changing out the gloplugs myself this weekend.

Thanks,
-Glenn

Glo Plug Issue - Advise need

The symptoms sound suspiciously like a bad glow plug harness that many other members have experienced. Not to slight your dealer but I would consider checking the resistance yourself with a meter, or if any members are in your area, to help out. I have a 2000 Jetta and receive a similiar code about every six months; I reseat the harness, clear the code, and wait for the next one. I check the GPs and glow plug relay and all check out OK. I will be replacing the harness when I get around to it.

If one glow plug is burned out and two are of the wrong resistance you may want to go through VW's customer assistance for an out of warrantee claim. maybe I'm wrong but I find it unlikely that the glow plugs would go bad so soon.

Good luck.

Glo Plug Issue - Advise need

At first, I suspected it was the harness. The harness had been replaced a year earlier under warranty. I figured this was the same problem. I told the dealer this when I dropped the car off (I had already run the diagnostics).

When they called back, they said the problem was a bad glo plug. I'll get a replacement and change it out this weekend.

I am curious about the low resistance they said was on two of the other plugs. Does anyone know what the upper and lower limits of the gloplugs should be?

Thanks,
Glenn

Glo Plug Issue - Advise need

Just (probably unecessarily) put glo plugs in mine and they were about 5 ohms. The ones I took out were about 7 ohms. The intermittent code generated on mine set off the Check Engine Light - which stayed lit until one of the VAG-com gurus reset the fault code.

Nothing has come back on...yet. Try to get a thinwall 10mm socket if you can find one - it'll make it so easy you'll gag at the idea that a dealer is even asking over $400 for this job.

I am dreaming but it would be a better world if auto dealers just gave up on the rapine & pillage mode. I mean there ought to be some sort of upper limit to their greed - charges/estimates like these border on the obscene (and from the other side of the border).

Glo Plug Issue - Advise need

It is a job you can easily do yourself. Look here for info on how to do it. If the dealer says you have a bad plug, thats probably all you need to change. Don't worry about a harness unless the plugs check out ok. The resistance should be between 0.5 ohms to 1.5 ohms. Any higher than that and it could throw a code. When the dealer says you have two plugs with low resistance, those two might be your good ones. A bad one will have no resistance and one thats on its way out has high resistance.

Buy the plugs online at www.vwparts.com ($20 each here ). You need the 10mm ones. Or you can bid on a set here . There is no need to do this asap as it does not affect drivability. Once you have replaced the plugs, test them again and get your CEL cleared by someone with VAG-COM, Autozone, or your local dealer. If they are customer service oriented, they shouldn't charge more than $20-$30 to clear it for you. It takes less than 5 min to do.

Good luck with this and if you have any more questions, feel free to e-mail me.

Glo Plug Issue - Advise need

No we owners don't know the absolute limits, or the relative limits, on the glow plug resistances. Without use of expensive measuring devices these low resistances cannot be accurately known - measuring devices like a four-lead Kelvin Bridge. This is because the lead resistance of a common resistance meter is a large fraction of the indicated resistance. Worse, the typical meter's resolution is too coarse to indicate even useful - beyond 'go/no go' - numbers.

The relative difference allowed (without setting the DTC) is set by the comparator circuit in the Glow Plug 'relay' -J52. In addition to the circuitry associated with its 'solenoid' functions, J52 also contains a circuit that compares the current in each of the two pairs of GPs. The associated shunt resistors are trimmed to extremely low resistances to drop only voltage appropriate to an IC.

One of the first requirements of the Output Diagnostic Test Function 03 for Engine System 01 (the OFRM's troubleshooting for this circuit) is four identical glow plugs. Changing one GP may or may not cure your problem. For instance, if you change one with high in specification resistance, the differences may become too great and still set a DTC.

Remember that for resistances in parallel - as the GPs are - the total resistance of the circuit is the reciprocal of the sum of the reciprocals of the individual resistances. Rt = 1/(1/R1 + 1/R2 + 1/R3 + 1/R4)

Good luck. I spent all this time writing this because I am an idiot and expect to continue to be ignored. By all means, 'easter egg' your components until the problem goes away. As I say, good luck.

Glo Plug Issue - Advise need

Thank you to everyone for your help. I have a set of four new plugs on order and hopefully I wil be changing them out next weekend.

Thanks again,
Glenn

Coincidentally my DTC:16764 just set after staying clear since being reset at about Christmas. I pulled the ECT sensor to energize the GPs for the default long time and hopefully cook out some moisture/corrosion. Apparently it worked again. We'll see for how long. Your Mileage May Vary.

Hi Doug,

I am at a loss why you seem to think that a harness can not be the cause of a DTC. I am not an engineer so I can't quantify my beleifs, but I can speak from personal experience.

My CEL was thrown 4 times within a 6 week period. Each time I checked the plugs, cleaned the terminals, tested the harness by unplugging the coolant temp sensor and checking for 12v from each terminal. All checked out ok, but still the CEL returned. So from advice from others on this forum I changed my harness for $30 and have not had a single issue now for 5 months & almost 20,000km. And I am not the only one who has cured their problem by replacing the harness.

Why would a seemingly simple part as a harness cause this? I wanted to find out so opened my old one up and found corossion inside. Pics can be seen here This corrosion/scorching can not be detected unless taken apart and cannot be cleaned because of its location. Replacement of the harness was necessary and I did not merely throw parts at it till it was resolved, I went in a logical order and tested the plugs first - all ok, then spent $30 to try a harness before moving on to the much more expensive relay. Well, it WAS the harness and all is now well. $30 is not too much to spend and if it doesn't work, oh well. It ruled out another possibilty. I didn't spend hundreds of dollars to have a dealer throw parts at it.

What more can I say, it worked for me, it has worked for many others too. My guess it will work for you too if your code returns in the near future. What do you have to loose? $30? Its the best $30 I spent on maintenance since I bought my car.

I would also have to ask why someone wouldn't simply disconnect the harness prior to testing the resistance of the glo plugs and get all the ancillary "stuff" out of the circuit. that should still permit a relatively accurate measurement of the resistance of each glo plug. precise to several decimal points? of course not but you are seeking consistancy, no? unless you think all four have gone south at once...

i, too, am not an engineer but i sure have fixed a heck of a lot of equipment over the years as an electronics technician. and i wouldn't dream of testing any componenet in the circuit if there is an easy way to test it out of the circuit - for exactly the reasons mentioned.