Glow plug fault

[Beach0433]

New issue popped up the other night on my way from Indiana to Iowa.
P13d0,13d3,13d6,13d9.
While driving along the interstate felt a stumble and then very little power. With glow plug light flashing. I could clear it while driving and would run normally for a period. But would happen again. I’ve checked all the wiring for the glow plugs and to my eyes it all seems good. I’m leaning towards the glow plug relay since I’m getting codes for all of them at once. Also I don’t have vcds. Hoping for some of your thoughts.

 

[Vince Waldon]

A flashing glow plug light is a "fix me RIGHT NOW" engine fault warning, generally not actually related to the glow plugs, for reasons known only to the German engineers that designed 'er.

That said, you can be pretty sure this is not just a glow plug issue.. as that would not cause a stumble and then low power.

There are about 20 different causes, and the fastest cheapest easiest approach would be a full scan with a VAG-specific scanner like VCDS. Generic scanners that can't speak VW will often miss many of the important FIX ME NOW codes.

Everything else will be an interweb guess, and that can get expensive quick.

 

[turbodieseldyke]

These glow plugs have a 2nd function as cylinder pressure sensors. With all 4 going bad at once, my internet guess would be the wiring harness, and not at the plugs where it might be easily seen.

 

[Beach0433]

yeah I know the glow plugs function as a cylinder pressure sensor as well. This is my thought on the stumble. CPU request a cylinder pressure reading and doesn’t get it so it put engine into limp mode for safety. I can clear the code and drive the car. Once I turn the car off and go to restart the codes are present again with just the key on. Which says to me the glow plugs aren’t passing the the cpu diagnostic on them ie. not getting power. So makes me think either relay or wiring. Hoping for relay as it’s easier to change than chase wires.

 

[turbodieseldyke]

Relays are for heavy current. There's no relay for sensor wires.

 

[Vince Waldon]

Assuming you are driving a standard North American 2006 Jetta you have a PD engine, and no pressure transducers in your injectors.

The ECU would check for continuity to the injector coil, but if there was an actual problem you'd have misfire codes, an obvious engine miss, etc.

Honestly, find a good scanner and let the car tell you what's wrong... it really really wants to!

 

[turbodieseldyke]

I assume he has a common-rail, since he posted in a CR model subforum and the P13Dx codes are for Internal Pressure Sensors

 

[P2B]

OP should let us know what vehicle has the issue and/or update his signature.

 

[Beach0433]

My apologies. It’s a 2013 Passat 2.0.
I’d love to update my info but can’t remember how lol

 

[RSH]

There is a VW TB about glow plug fault codes and a general outline on diagnosing the the issue.

https://static.nhtsa.gov/odi/tsbs/2016/MC-10121091-9999.pdf

 

[eugene89us]

I love it how it says to swap glow plugs, same system as they recommend swapping injectors and spark plug coils on petrol cars. I don't know how Volkswagens are with their glow plugs (I just know their glow plug connectors are very easy to break), but other diesel cars have had issues with glow plugs getting stuck. I think it is the collection of soot on flow plug tip that causes it to stick. So you would loosen it and then it would catch. So you have to go back and forth tightening and untightening with use of penetrating oil for fear of snapping a glow plug and having to drill it out. Glow plugs give me the heebie-jeebies.