This is Citroen's way of cleaning your filter(s), it works too, My C5 was getting old (120,000+ miles) and had to use this information a couple of times. Jump: C4 The Garage ICE / Sat Nav/Bluetooth etc. Car Care Technical Questions Market Place The Lounge Mods and Styling, Chassis, lowering, wheels etc. Interior and lights C4 Coupe and Hatch
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