Citroën C4 diagnostics
Citroën C4 (2004–2026): free AI diagnosis by symptoms, fault codes or a dashboard photo — plus OBD-II reading right in the browser.
What usually goes wrong on the Citroën C4
- На 1.6 THP (EP6DT) растягивается цепь ГРМ и закоксовываются впускные клапаны — рокот на холодную, троение, ошибки фаз.
- Корпус термостата и помпа на EP6 текут антифризом, нередко с перегревом.
- У C4 первого поколения с неподвижной ступицей руля перетирается подрулевой шлейф: пропадают кнопки на руле, сигнал, ошибка подушки безопасности.
- На 1.6 HDi забивается сажевый фильтр FAP и закоксовывается клапан EGR, машина уходит в режим ограниченной мощности.
These are the model's typical weak points, not a verdict on your particular car: the AI keeps them in mind, but the diagnosis comes from your symptoms and your codes.
Fault codes that come up most often
Click a code to open the breakdown: what it means, how serious it is and what to check first.
Describe the problem
Tell the AI chat what your Citroën C4 is doing — noises, warning lights, behavior. It knows the model's typical weak points and asks the right follow-up questions.
Read the codes
Plug an ELM327 adapter (over USB or Bluetooth LE) into the OBD-II port and read fault codes right in the browser on the Connect adapter page — no software to install.
Get a verdict
The AI ranks the likely causes, tells you what to check first and whether it's safe to keep driving.
Problem with your Citroën C4?
Describe what's happening or paste the fault codes — the AI will narrow down the cause and tell you what to check first.
Start diagnosisWhat can be read from this car
Through the OBD-II port on your Citroën C4 you can read engine fault codes, live sensors, readiness monitors and a freeze frame — with an ELM327 adapter, including right in the browser. If the car has a CAN bus (roughly 2008 and newer), the program additionally polls the remaining modules:
For a deeper scan of your Citroën C4 — all modules, live data, freeze frames — use the free Diagnost program for Windows or macOS with an ELM327 adapter.