Also to clarify a bit...The vehicle has about 105,000 miles. Is it generally accepted to just replace the TV, or does a good cleaning usually take care of the issue? Obv if I see an issue with the actuation, or with the gears...yes. Thoughts? Thanks.
2013 VW Golf TDI issues / Codes
So its been a few sordid months with my wife's TDI. Here's the history:
It started with hesitation and loss of power, and a blinking coil dash light. She took it in to a local mechanic and the second hand info I got was that there was "Something wrong with a flapper." My wife ordered a dieselgeek p2015 fix, and I helped get that installed last week, and thats when I got involved in this. After replacement, there really wasnt much of a change, so I pulled codes. We had a turbo Underboost code(P00AF, P0299), an EGR code (P0402), etc. Would not go over 2500 RPM. So after watching some of the vids on here, and based on the codes, I was thinking that the N75 or actuator was bad. I checked the vacuum system:
The N75 behaved much better after that. I cleared the codes, and went for a test drive. I was able to get RPM up to 4-5000, but I could still tell we werent normal power. Drove it hard to heat up the EGTs and came back to check codes. No more stored codes, but the original permanent codes were there, plus two pending/permanent codes. These may have been there originally as well, I'm not sure, as I didnt pull the codes at the start, but anyway, this is the latest:
![Font Screenshot Technology Darkness Multimedia]()
- P0638 - From what I am reading is the Throttle Valve? just below the EGR valve. I've read some people clean them up, and some people replace them, and some people change the little plastic gears on them.
- P13D6 - from what I can find is a glow plug/Chamber Pressure sensor for Cyl #3. Its not a stored or permanent code, so I'm thinking this could be a misfire/lack of air issue from the other problem.
So on to the question: I'm trying to decide where to go from here given the following.
1) When I was testing the VNT vane actuator, the video says that it should start moving at 2-3" of vac (
) and hit the stop at around 15-18". I think this one is stopping at 12. Granted the cheap vac pump gauge could be off a bit and all good...just trying to decide if I need to pull and replace or re-adjust a bit...I'm leaning towardVNT is probably fine.
2) Yesterday I yanked the battery, airbox, Cooling fans (better access to the Throttle valve), and pipe all the way back to the turbo inlet. I also pulled the sleeve off the charge pipe, and while it seems a bit dirty in there, nothing like others that I've seen in pics.
I figured I would go ahead and drop the TV and check that the butterfly moves smoothly, and maybe even pop the cover and look at the gears. Any other advice on this? Should I pull the VNT Actuator and check the vanes, or just focus on the TV for now since we dont have any VNT codes anymore?
Sorry for how long it is....Thanks for any help offered.
It started with hesitation and loss of power, and a blinking coil dash light. She took it in to a local mechanic and the second hand info I got was that there was "Something wrong with a flapper." My wife ordered a dieselgeek p2015 fix, and I helped get that installed last week, and thats when I got involved in this. After replacement, there really wasnt much of a change, so I pulled codes. We had a turbo Underboost code(P00AF, P0299), an EGR code (P0402), etc. Would not go over 2500 RPM. So after watching some of the vids on here, and based on the codes, I was thinking that the N75 or actuator was bad. I checked the vacuum system:
- First from the pump...28" consistently
- I checked the turbo vane actuator - held vacuum without loss.
- Then the N75 - I dont have VCDS (it arrives Tuesday), but Tee'd up Vac gauges on the pump to N75 inlet, and in between the N75 and Turbo Vane Actuator. It was inconsistent when it called for vac, so we just replaced it (N75).
The N75 behaved much better after that. I cleared the codes, and went for a test drive. I was able to get RPM up to 4-5000, but I could still tell we werent normal power. Drove it hard to heat up the EGTs and came back to check codes. No more stored codes, but the original permanent codes were there, plus two pending/permanent codes. These may have been there originally as well, I'm not sure, as I didnt pull the codes at the start, but anyway, this is the latest:
- P0638 - From what I am reading is the Throttle Valve? just below the EGR valve. I've read some people clean them up, and some people replace them, and some people change the little plastic gears on them.
- P13D6 - from what I can find is a glow plug/Chamber Pressure sensor for Cyl #3. Its not a stored or permanent code, so I'm thinking this could be a misfire/lack of air issue from the other problem.
So on to the question: I'm trying to decide where to go from here given the following.
1) When I was testing the VNT vane actuator, the video says that it should start moving at 2-3" of vac (
) and hit the stop at around 15-18". I think this one is stopping at 12. Granted the cheap vac pump gauge could be off a bit and all good...just trying to decide if I need to pull and replace or re-adjust a bit...I'm leaning towardVNT is probably fine.2) Yesterday I yanked the battery, airbox, Cooling fans (better access to the Throttle valve), and pipe all the way back to the turbo inlet. I also pulled the sleeve off the charge pipe, and while it seems a bit dirty in there, nothing like others that I've seen in pics.
I figured I would go ahead and drop the TV and check that the butterfly moves smoothly, and maybe even pop the cover and look at the gears. Any other advice on this? Should I pull the VNT Actuator and check the vanes, or just focus on the TV for now since we dont have any VNT codes anymore?
Sorry for how long it is....Thanks for any help offered.
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I pulled the TV just now. Really not very dirty at all.
but something is biding up the butterfly. For giggles I pulled the top cover and the plastic gears look fine. No real visible spots of wear. Not sure what is causing it to hang.
New one gets here tomorrow and hopefully that will resolve the issues.
Us? Bro I think you and I the only ones here. 😂
Thanks for the input Super. It’s fixed, and here’s my update for any of those who come after...
The TV install was pretty straight forward. Personally I would remove the airbox, and eFans just to give yourself as much room as possible.
No need to remove the Charge pipe Sleeve entirely. Just disconnecting the top is fine. There is enough give to get the TV out after you take the top part of the sleeve off the bottom part of the TV.
Also as another suggestion I got from a diff video I watched...put some paper towels in the chargepipe sleeve to keep from losing screws, sockets and other bits in there, if you happen to drop them.
When I pulled the old TV off, there was no way to tell what the resting position was supposed to be. And unlike a gas butterfly, this one is intended to rest open, not rest closed. Once I compared the actuation side by side it was even more obvious that the TV was sticking badly. Could I have cleaned it? Maybe. But breaking the two locator tabs to get the cover off, then tearing it all down, cleaning it, putting the car back together, and testing it, and potentially having to re-do it, wasnt worth the $130 USD I paid for the part. I'll likely take this old one and clean it up now.
After the install, I let the car warm up and both pending codes disappeared immediately. The test drive was a success, and power felt normal. The stored codes remain, but those should go away after a few driving sessions.
Looking back, while I had ~6 codes...I think only 2 were actual issues: the N75 and the TV codes. Those two parts failed the testing procedures. The others like underboost, was not a turbo or VNT actuator issue, but was a direct result of the two failed parts.
A final suggestion. If you own one of these cars, I highly advise you to get a vacuum pump and gauge. And a VCDS. (I didnt have VCDS, but I had a second person to help with revving, turning the car off/on, etc).
Best of luck to all. Thanks again @Super for the input.
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