Hello together. I have a problem with my C4 Picasso. A few weeks ago he just went out on the road. It came the error message: water in the diesel filter. You could not start the car either. OK, car towed, filter and crankshaft sensor (has the diagnostic device still displayed) replaced. 3 days later the same again. Also the message with the diesel fiiter again. I then measured the battery voltage with caution. Has 6,5 V indicated. The battery is already about 9 years in the car. OK, new battery is installed. No error message. Today it does not start again. All possible error messages follow up. Can it be that the first time (on the road) in the battery was a short circuit? Therefore 6,5 V. And now what is wrong with the ECU? Can one check the ECU somehow? After I changed the battery, the car jumped on without error messages. Does it read out the error memory again? Diesel, Automatic, BJ 2007