Got the P0638 code last night

herk1225

New member
Joined
Dec 21, 2016
Location
California
TDI
2011 Jetta TDI Sportwagen
A little background. I have a 2011 JSW TDI, 130k miles and I plan on giving the car back probably by april/may of next year. I recently got the P2015 error and from all the reading online and on here, I can fix it with the bracket or just ignore it since it doesn't really affect performance.

And last night, I started the car and immediately got the flashing glow plug light. I was able to drive home without any of the symptoms others have described(unable to throttle, slow pickup, limp mode, engine shudder, etc.) It drove just fine. I pulled the ODB codes and got P0638

I did a lot of reading and watching quite a few youtube video, most suggest that I try to clean the throttle body actuator valve first and see. So this morning, I started the car and the flashing glow plug light went away on its own.

My question is should I worry about this or is it just a dirty valve and it went away on its own. I certainly don't want to spend $1000 bucks getting this fixed since I am only going to keep the car for 4 or 5 more months.

I can still attempt to clean the valve but I am not so sure about taking the throttle body actuator off to clean it.

Any suggestions or recommendation is greatly appreciated. Thanks!
 

herk1225

New member
Joined
Dec 21, 2016
Location
California
TDI
2011 Jetta TDI Sportwagen
quick update. The flashing glow plug light came back after starting it warm. And it went away again after sitting in the cold overnight this morning. And when I started it again this afternoon, it came back. So looks when the dirt/gunk is cold, it doesn't trigger the sensors.

I'll attempt to clean it tomorrow and see.
 

samtem

New member
Joined
Jan 30, 2017
Location
Houston
TDI
Golf 2011
Oh man, any updates on this one?

Having the same exact problem right now, but naturally don't want to put any money into this thing. Any links for best youtube tutorials?

Killed the cars electrical the other night. Seemed fine this evening but about to drive a bit more and see how's it doing.

edit:
I have a 2011 golf tdi, 55K miles
 

Willis81

Well-known member
Joined
Oct 31, 2007
Location
Centerville, UT
TDI
2012 Golf TDI, ML320 CDI
I recently had this error code pop up. Initially it was just the CEL, then this morning the glow plug light was coming on, roughly once every 10-15 seconds. Almost missed it because it was so infrequent. Parked it while I was at the gym and when I came out the glow plug light was flashing, performance was poor, hesitation etc. I parked it and drove my other car to work. Most of the searching on this code indicates that cleaning the throttle valve might help (temporarily). Does anyone know if this is something that would be covered under the extended emissions warranty? I'll let the dealer take care of it if it's covered, but if it's definitely not covered then I won't even bother taking it in and I'll replace it myself and do the adaptation.
 

Tdi-nj

New member
Joined
Nov 21, 2019
Location
New Jersey
TDI
2011 Golf tdi
I recently had this error code pop up. Initially it was just the CEL, then this morning the glow plug light was coming on, roughly once every 10-15 seconds. Almost missed it because it was so infrequent. Parked it while I was at the gym and when I came out the glow plug light was flashing, performance was poor, hesitation etc. I parked it and drove my other car to work. Most of the searching on this code indicates that cleaning the throttle valve might help (temporarily). Does anyone know if this is something that would be covered under the extended emissions warranty? I'll let the dealer take care of it if it's covered, but if it's definitely not covered then I won't even bother taking it in and I'll replace it myself and do the adaptation.
Same thing happened to me last night. Flashing coil, P0638.
Anyone know if its covered by the DIESELGATE warranty?
 

Strong Malt

Member
Joined
Dec 19, 2013
Location
Utah
TDI
2010 Sportwagen
Hey All, I have a I have a 2010 JSW TDI, 176k miles. Recently threw the P0638 code. After watching a few youtube videos I removed the throttle body, cleaned it thoroughly with carb cleaner and re-installed it. Code, engine and (blinking) glow plug still there.

Any updates from anyone on the best resolution here? Thx much.
 

Porch

Veteran Member
Joined
Jul 29, 2019
Location
Asheville, NC
TDI
2011 jetta sportwagen tdi 6spd
💯 a warranty issue, if you haven't modified your engine or exhaust. You could even get a new cylinder head if they break off a glow plug in it while they're doing this repair, like my car did with 300 miles left on the warranty!

EDIT: just saw the dates on the warranty comments. I hope there's still people out there with warranty left on these cars, free dealer service and brand new loaner cars was a novelty and dare i say, fun, experience for me with my car.
 
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