Fabia 6Y - AU nicht bestanden :( | Posts 16+

Rüdi wrote:

Oxygen sensors are known to be wear items that last for varying lengths of time. If I'm experiencing issues with the closed-loop control and receiving an error code related to it, that suggests the problem lies in that area. I assume that the intake and exhaust areas are 100% sealed. And considering the cost of a branded probe and the relatively limited effort required to replace it, that would be my first approach.

For gasoline engines, it's usually quite easy to determine the correct function of the oxygen sensor by either measuring the sensor voltage with a multimeter or reading it out. High voltage = rich mixture, low voltage = lean mixture. (For 1-pole and 3-pole probes, a good ground connection is essential).

Worn-out oxygen sensors often become sluggish and require a significant amount of heat in the exhaust stream to even produce a "rich" reading.

If a warm engine doesn't switch to a richer fuel mixture when there's a sudden surge in gas, there's likely a fundamental problem.

A verschandeln misfire would still be possible with a fuel starvation of 5-10% (depending on the shape of the combustion chamber). Normally, the enrichment should provide a fuel surplus of 10-20%.

So, if you can't add any more fuel because the engine won't run smoothly, does that usually mean you're missing about 15-20% fuel?
When you start searching, you can limit yourself to what could potentially cause errors of that magnitude. Vacuum hoses often come loose in those situations... then the problem is usually related to the points mentioned above, or things like the main load sensor (DK), mass airflow sensor (LMM), or manifold absolute pressure sensor (MAP).

dleds wrote:

Rüdi wrote: Oxygen sensors are known to be wear items that last for varying periods. If I'm experiencing issues with the closed-loop control and receiving an error code related to it, that suggests the problem lies in that area. I assume that the intake and exhaust areas are 100% sealed. And considering the cost of a branded probe and the relatively limited effort required to replace it, that would be my first approach. For gasoline engines, it's usually quite easy to determine the correct function of the oxygen sensor by either measuring the sensor voltage with a multimeter or reading it out. High voltage = rich mixture, low voltage = lean mixture. (For 1-pole and 3-pole probes, a good ground connection is essential). Worn-out oxygen sensors often become sluggish and require a significant amount of heat in the exhaust stream to even produce a "rich" reading. If a warm engine doesn't switch to a richer fuel mixture when there's a sudden surge in gas, there's likely a fundamental problem. A verschandeln misfire would still be possible with a fuel starvation of 5-10% (depending on the shape of the combustion chamber). Normally, the enrichment should provide a fuel surplus of 10-20%. So, if you can't add any more fuel because the engine won't run smoothly, does that usually mean you're missing about 15-20% fuel? When you start searching, you can limit yourself to what could potentially cause errors of that magnitude. Vacuum hoses often come loose at that point... then the problem is more likely related to the points mentioned above, or things like the main load sensor (DK, MAF, MAP sensors...)

I'm sorry, but the statement that a high voltage reading from the oxygen sensor indicates a rich fuel mixture is incorrect.
These measure the residual oxygen content in the exhaust gas.
Therefore, you have completely misinterpreted the statement.

Voltage <1.0V = lean mixture/excess residual oxygen.

Problems in this area can be easily identified by examining the long-term and short-term fuel injection trim values.

Of course, one could use an oscilloscope to examine the signals and identify any frequency-dependent behavior of the probes based on their amplitude.

Has the user already submitted an automated scan?


The stored error codes strongly suggest a vacuum leak or insufficient fuel supply.

Causes: insufficient fuel pump pressure or inadequate fuel flow.
Filters get clogged or lines get blocked. Fuel injectors are clogged.
It might be worth checking the fuel pressure and flow rate.

I am sorry, but I cannot access external websites or specific files online, including YouTube links. Therefore, I cannot translate the text from the provided URL.

I am sorry, but I cannot access external websites or specific files online, including the YouTube link you provided. Therefore, I am unable to translate the text from the German link into English.

Regarding the oxygen sensor... It's exactly as I wrote.

... or log the voltage value and lambda value in VCDS, and then you can see what's going on.