Hello, we have a C4 diesel from 2004. So already a considerable age, but still runs well.. actually. two years ago he had already spit out error messages in the mountains, stopped and let us to the workshop, where you could not read any error messages any more. So we drove further, everything went without further messages. About a month ago the engine went off at traffic lights simply, after a visit to the factory This was the case again, instead of finding nothing in which one could not find anything. Now he complains with “gas system defective” at every start, were already two weeks ago in the workshop. They read out the error memory with the result that the filter should be filled up once and the additive injection does not work. You had looked at the filter, yes, it is already a little bit added, but should still work loosely. And the message with the additive injection is from a a defective sensor has been triggered in the tank lid, so he didn’t know how much additive has to be added to it. Um… what additive? We have 180000km now on the box and didn’t have to refill an additive or have no tank lid somewhere for it… A guess now is that a workshop had made a firmware update at some point and played a wrong one that assumes we have an additive injection? And now we are x kilomet or is the idea of complete bullshit? Are no professionals in this matter and the workshop apparently not. Have another appointment on Tuesday, but wanted to hear from you about whether there were similar experiences.