I thought that topic with the dirty throttle flap to pick up and how to clean it. Background is that the day before yesterday the check light went on and the error code 16891- Idle speed control over set value Causes throttle flaps control unit – occurred. In the workshop they wanted to order parts again, install them and I quote: “Let’s see if the error is gone”. That smelled for me immediately after arbitrary repairs with thick prices without But luckily there is MT and I also found out immediately that a dirty throttle valve or a broken vacuum hose can be the cause. I removed the throttle valve, cleaned it (that was bitterly necessary!) and re-learned it. I found how to do this in this very useful guide, which helped me solve the problem.Instructions The instructions refer to golf and bora, but the throttle valve is also with the lupo (at least 1.0 AUC) quickly found. In addition, simply decompose the engine cover and you can see it already. During the removal I also found a broken hose, which I initially covered with Tesa, until I bought a new one. After I had installed the hose and the throttle flap again, I had still learned the throttle. by disconnecting the battery also the error message was deleted and the check light is off. The throttle flap now and again I become sour I have the feeling that the motor is running a little more spooky. But it can also be imaginable… So if the mistake occurs in you, clean your throttle first, you could save a lot of money….