CITROEN DS4 Owner's Handbook Manual page 241

Petrol engines
The various caps and covers allow access for
checking the levels of the various fluids and for
replacing certain components.
1. Power steering reservoir.
2. Screenwash and headlamp wash reservoir.
3. Coolant reservoir.
4. Brake fluid reservoir.
5. Battery/Fuses.
6. Fusebox.
7. Air filter.
8. Engine oil dipstick.
9. Engine oil filler cap.
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