Just took my 2001 Beetle TDI to the dealership because check engine light came on out of the blue. Have had no problems with car starting or anything even on colder mornings. Dealership says glow plugs need to be replaced (a wear item that needs replacing between 40,000-60,000 miles). I have just 50,000 on the car but I thought these things were suppose to last for 100,000 miles. Also, shouldn't the glow plug light have come on to let me know there was a problem?
beetlebug
TDI Glow Plugs
Moderator: Fatmobile
Just went thru the same thing. Take a meter and measure each glow plug.
The one with no resistance or open is the bad one. Also read on another forum the harness can be bad so be careful taking it off the glowplugs(it sounded very expensive). I only relpaced the bad one.
Bob
The one with no resistance or open is the bad one. Also read on another forum the harness can be bad so be careful taking it off the glowplugs(it sounded very expensive). I only relpaced the bad one.
Bob
84 TD Jetta tweaked pump
01 TDI Jetta stock
98 Dodge diesel chip injectors 4in exhaust 325hp 700lbs tq
01 TDI Jetta stock
98 Dodge diesel chip injectors 4in exhaust 325hp 700lbs tq
I too have a 2001 New Beetle TDI. A check engine light (CEL) from problems with the glow plug circuit is a common problem. I have had it myself.
You should go to tdiclub.com and look at the posts in the A4 Chassis general maintenance forum, starting fall of 2003 to spring of 2004, we have pretty well trampled tthis issue to death over there.
Just in case you can't find it there, or you are in a hurry, here is a Reader's Digest shortened version.
In the engine control electronics there is a function that checks to make sure that all the all the glow plugs are pulling exactly the same current, and the engineers set the allowable current difference way too low. You can have four working glow plugs and still get a CEL.
Unlike the older VW diesels that used a bolted connection, the TDIs use a push on terminal like a spark plug wire and it has been found that this connection gets iffy do to corrosion. Not so bad as to kill the glow plug, just bad just enough to turn on the CEL. You want to pull the glow plug harness off the glow plugs and clean the harness terminal and the top of the glow plug with electrical contact cleaner spray (Caution: Some contact sprays are flammable. Do Not do this on a hot engine. Not to mention you have to get your hands down in some tight quarters and unless you have the smallest hands or hide like a politician you'll burn you hands on the hot cylinder head). Any good electric contact cleaner will likely work, some people have a special thing for DeOxit D5 cleaner.
While you have the harness off, it would be good to check the glow plugs with an ohm meter. They all should be around 1.2 to 1.5 ohms, and whatever resistance they are they all should be nearly equal. If you do have a bad plug, changing it is like changing a spark plug. Some guys say just change the bad one, others say change all four if one is bad, both seem to have reasonable success. I doubt any of your glow plugs are bad, my guess is that it is the harness.
While there were problems with the glow plug relay on the earlier TDIs, the relay was upgraded by 2001 and this is not likely the problem.
If you don't mind the CEL, and you are not in an inspection state you could do nothing. I ran all last winter in the Detroit area with a CEL and had no problems starting.
That is all, I think I know.
Piper106
You should go to tdiclub.com and look at the posts in the A4 Chassis general maintenance forum, starting fall of 2003 to spring of 2004, we have pretty well trampled tthis issue to death over there.
Just in case you can't find it there, or you are in a hurry, here is a Reader's Digest shortened version.
In the engine control electronics there is a function that checks to make sure that all the all the glow plugs are pulling exactly the same current, and the engineers set the allowable current difference way too low. You can have four working glow plugs and still get a CEL.
Unlike the older VW diesels that used a bolted connection, the TDIs use a push on terminal like a spark plug wire and it has been found that this connection gets iffy do to corrosion. Not so bad as to kill the glow plug, just bad just enough to turn on the CEL. You want to pull the glow plug harness off the glow plugs and clean the harness terminal and the top of the glow plug with electrical contact cleaner spray (Caution: Some contact sprays are flammable. Do Not do this on a hot engine. Not to mention you have to get your hands down in some tight quarters and unless you have the smallest hands or hide like a politician you'll burn you hands on the hot cylinder head). Any good electric contact cleaner will likely work, some people have a special thing for DeOxit D5 cleaner.
While you have the harness off, it would be good to check the glow plugs with an ohm meter. They all should be around 1.2 to 1.5 ohms, and whatever resistance they are they all should be nearly equal. If you do have a bad plug, changing it is like changing a spark plug. Some guys say just change the bad one, others say change all four if one is bad, both seem to have reasonable success. I doubt any of your glow plugs are bad, my guess is that it is the harness.
While there were problems with the glow plug relay on the earlier TDIs, the relay was upgraded by 2001 and this is not likely the problem.
If you don't mind the CEL, and you are not in an inspection state you could do nothing. I ran all last winter in the Detroit area with a CEL and had no problems starting.
That is all, I think I know.
Piper106
Continued.
Remember that if you clean the glow plug harness contact, and put it back together, even if you are successful, the CEL will not go out by itself immediately. The system hold the code for weeks, you need to go in and reset the system with a VAGCOM to clear the CEL. Some guys just pull the battery cable for a few seconds to reset the system and turn out the CEL, but that could unset the immobilizer and the radio/sound system security device, so I personally would not do that.
It has been found that on some harnesses that the contacts get so bad, that no amount of cleaning will get the current back to where it should be and the CEL keeps coming back. At that point you might want to replace the glow plug harness.
There is no connector in the engine compartment on this wire, so some stealerships replace the whole engine compartment wiring harness and this is BIG bucks (one reported estimate was $1200!!).
The generally agreed best repair is to replace the end of the glow harness. A 18" long or so section of the glow harness (the four glow plug connections and about 6" of lead) is available as a repair part for less than $40. You cut the old end off, and splice the new end to the old supply wires in the engine compartment, and you are good to go. Dealerships that aren't out to totally sc**w their customers do it this way, expect to be charged about 2 hours of labor at their going rate. You can do it at home if you are reasonably handy with wiring, expect the job to take a couple of hours if its your first time, less if you have done this before. There are detailed instructions over at tdiclub.com.
Piper106
Remember that if you clean the glow plug harness contact, and put it back together, even if you are successful, the CEL will not go out by itself immediately. The system hold the code for weeks, you need to go in and reset the system with a VAGCOM to clear the CEL. Some guys just pull the battery cable for a few seconds to reset the system and turn out the CEL, but that could unset the immobilizer and the radio/sound system security device, so I personally would not do that.
It has been found that on some harnesses that the contacts get so bad, that no amount of cleaning will get the current back to where it should be and the CEL keeps coming back. At that point you might want to replace the glow plug harness.
There is no connector in the engine compartment on this wire, so some stealerships replace the whole engine compartment wiring harness and this is BIG bucks (one reported estimate was $1200!!).
The generally agreed best repair is to replace the end of the glow harness. A 18" long or so section of the glow harness (the four glow plug connections and about 6" of lead) is available as a repair part for less than $40. You cut the old end off, and splice the new end to the old supply wires in the engine compartment, and you are good to go. Dealerships that aren't out to totally sc**w their customers do it this way, expect to be charged about 2 hours of labor at their going rate. You can do it at home if you are reasonably handy with wiring, expect the job to take a couple of hours if its your first time, less if you have done this before. There are detailed instructions over at tdiclub.com.
Piper106
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Lektrikman
- Glow Plug
- Posts: 2
- Joined: Tue Dec 06, 2005 9:25 pm
My wife has a 2000 Jetta TDI that has recently displayed a check engine light. When I read the diagnostic codes it indicated a problem with the glow plug system. I spoke with a tech at my local VW dealership and he indicated that there is a temperature sensor in the coolant header on the end of the engine that tells the glow plug system how long to stay on. The OE sensor with the problem is black in color and is being replaced with a newer sensor that is green in color. I checked mine and I have the black sensor, so I bought a new green sensor and plan to change it when I change the timing belt in the next couple of weeks. Maybe isn't a factor but worth being aware of...........-
mycoleptodiscus
- Glow Plug
- Posts: 18
- Joined: Thu Jan 19, 2006 3:06 pm
if you are at all handy...
2000 Jetta TDI 105k miles. The glow plugs are a piece of cake to do. All you need is metric deep-well sockets from Sears. They are about $16 ea. Replace ALL of them while you're at it. $60 is CHEAP for car repair. The harness is cheap as well from VW, $40 or so. You need to cut off the terminals that come on the harness form VW and splice in the wires, but all you need is some butt connectors and some electrical tape. When you have all the work done, take it to a shop and have them reset the codes. I am from MN and my TDI started to not start at -10F with this problem.