GOLFMK8
GOLFMK7
GOLFMK6
GOLFMKV

Code p0171

Beerial

New member
Location
Portland OR
Car(s)
Mk4 GTI and Mk5 GTI
2008 VW GTI 2.0T. Threw a check engine light at me this morning, I opened my hood and found my gas cap gone. Put on the one from my 1.8T and put new oil in because it was very low and oil was visibly splattered on the cover. RPMs rise slightly while parked or stopped at red light. Couldn’t find my code scanner so I took it to autos one and was told PCV Valve. Person at auto zone asked if it smelt like gas and said it was a valve solenoid if it did (I don’t smell gas but it’s only been a day). Any ideas or should I just replace the PCV valve? I need this fixed ASAP
 

GTI's

Drag Racing Champion
Location
MD
Take a look at your vacuum pump hoses to the brake booster, these plastic hoses break and split. You have a '08 so you might have one or two hoses depending if you have FSI or TSI.
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
As with most codes we see with these, there is always more than one possible reason...unfortunately.

But as GTI's said, check the tubing. You aren't able to see the full circumference...so feel for splits.
All tubing attached to the intake manifold utilizes and depends on the vacuum within the manifold for their functioning. They all have check valves so to shut when boost is present. So if any of those tubes develop a leak/split...then extra air enters when the engine runs in vacuum. Then the O2 reports a lean condition for having extra air and then corrects itself by adding fuel.
 
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