Flashing Glow Plug and Loss of Power While On Highway

Virtality

New member
Joined
May 25, 2020
Location
Colorado
TDI
2015 VW Jetta SEL TDI
When did it occur:
I have a 2015 Jetta TDI SEL with 85,000 miles on it. While driving on the highway at approximately 85 mph I got a flashing glow plug light and lost a significant amount of power. The car would not go faster than 80 and when accelerating from a stop it felt like I only had one cylinder. It was opening the waste gate to engage limp mode. Turning of the car and turning it back on resolved the issue for a few days until it happened two more times (both while driving on the highway at speeds over 75 mph. Every time it was simple as turning off and back on to fix.

Diagnosing:
I tried reading the code with OBD11 and although it acknowledged it had thrown a code three times, it couldn't provide any information on it. After hooking up a VCDS cable we found the code: P0299 (Boost Pressure Regulation - Control Range Not Reached/Low Boost)
From what I found the way my car acted combined with this code was most commonly a vacuum leak but could also be a charge pressure pressure control or turbocharger issue. After testing the turbo with VCDS we were very confident that it was ok which left only two things.

Finding the vacuum leak:
These are most commonly found with $700+ machines at shops but I wasn't going to spend that much. I went to harbor freight and picked up a multi-use transfer pump ($7), bought a cheap cigar from a gas station ($1), and grabbed a disposable rubber glove and some tape (already had some). I disconnected the large intake line after the filter (on the engine side). I stretched the glove over the intake to make a seal and then made a small insertion in the glove to put the output line from the transfer pump. I taped the connection between the glove and the output line to create a good seal after that. On the input side of the pump i placed the cigar on (the side of the cigar you smoke from not light). I taped the cigar on after to create a better seal and prevent it from going anywhere. I had a friend start using the pump while i lit the cigar and smoke got pushed in the intake system and within a few seconds we could see the smoke spilling out near the turbo.
It was a connection between a line that has a sensor and connects to the valve cover and the intake line.
Although this might not be where your leak is, the method works flawlessly and hopefully helps you. It was extremely easy to perform and if anyone needs help please reach out.

Fixing the leak:
I haven't been able to figure out what this sensor/connection/line is yet but once the dealership opens again and will go in and find out. I can't imagine a new fitting costing more that $50 but I will update this when i find out.




If you want pictures or video of anything please direct message me and I'll see what I can do to help.
 

tdi_514

Active member
Joined
Nov 8, 2018
Location
Montreal, Canada
TDI
2014 Jetta TDI DSG
I had the exact same issue.
When I went to the dealer they told me it was the turbo sticking and they changed it under warranty.
 
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