TFSI - Oil leak - Not a VCDS related question? or is it?



Ross-Tech Employee
Ross-Tech Employee
Jan 29, 2014
Reaction score
16.4905° S, 151.7375° W
Hi there,

I would like to share with you a recent tech inquire that prompted me to write this quick Tech Tip
about a 2009 Passat with a couple common fault codes and a condition that we are starting to see more and more of.

Vehicle: 2009 Passat
Engine: CCTA - 2.0L TFSI, Chain drive

Engine Fault codes:

P0171 - Fuel Trim; Bank 1: System Too Lean
P119A - Fuel Pressure Sensor (G247) : Malfunction

We checked the Measuring Value Blocks Group [032]-Lambda Control (Mixture Adaptation)
Field 1 (Adaptation (Idle),Bank 1) = [5.6]
Field 2 (Adaptation (Partial),Bank 1) = [-2.3]

Had the customer run the Basic Settings Test [107], engine warm (80'C+)
- System Not Okay

I then asked if he noticed if there was an oil leak, between the Engine and the Transmission?
- There was some seepage, not a lot but enough to leave a few drops on the floor.

At his point, I suggested he caps off the crankcase breather connections at the intake manifold and the turbo inlet pipe,
eliminating the engine and its newly replaced crank case breather from influencing mixture control (false air).

And now run one of my favorite Basic Settings tests again, BS-107..

This time, it indeed passed, as I suspected it would.

So it looks like this oil leak needs to be fixed and I suspect he will find what I found last year working on a TFSI Passat engine, see pictures below.

- Now before everyone starts pulling the transmissions out of there vehicles, it is very important to verify an oil/air leak, or better yet smoke test the crank case with 1-2psi and check for seal leaks.

Looks normal, right???


Larger version

This paper like ring was actually stuck on the crankshaft!
- POS :(


Larger version

For more information about Measuring Value Block [032] and fuel trims:


Hope this helps,

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