C4 Water Sensor Error

I had a similar problem with my Citroen C4 some time ago, though mine wasn't as new. The malfunction indicator was also lit. It turned out to be a faulty connection to the moisture sensor. Have you checked the cable and plug connection for any obvious damage or corrosion? A defective cable can lead to all sorts of issues with modern cars.

Thanks! Where exactly is this sensor located in the engine compartment? I'm not very experienced in sensor testing, but I want to rule out an obvious issue before going to a workshop.

Without seeing your exact engine setup, it's difficult to pinpoint the location. The water sensor is usually close to the fuel filter. Given the rough running, it's best to get it checked by a professional. Ignoring it might cause further damage. The stored error should help them diagnose it quickly. I ended up paying around 95€, which was acceptable considering the effort.

Thank you, that's helpful! I'll check the area around the fuel filter. If I don't find any obvious problems, I'll take it to a workshop as you suggested. Good to know what to expect in terms of cost, too. Thanks again!