If the C4 Aircross (Diesel) is at operating temperature, then one hears a rattle in the intermediate gas range. At the same time, this rattle is accompanied by a clear stroke in the steering wheel and in the pedals, but both occur only when the outside temperature is well above 15 degrees and the engine has operating temperature (90 degrees). The workshop of the used car dealer was surprised and then the screws on the bend were then attached to the car. Rattlen was no longer there on the way home, but then came back on the next longer journey. What can it be and how can one document this so that the workshop can actually improve within the scope of the used car warranty?