Citroen C4 Picasso Cabin Air Filter: Intervals, Fitment & Warning Signs

On the C4 Picasso, a genuine, real mistake worth avoiding: aerosol sanitiser spray can gum up and kill the blower fan — plus a free DIY drain test.

Illustration for editorial purposes

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OEM Part Number: confirm via VIN — cabin air filter (aftermarket) Mann CU3039-2 / Mahle LA138

Accuracy note: Covers the Citroen C4 Picasso (2013-2018) as listed in the UK aftermarket catalogues. A cabin filter is a cheap part, but it is bought by number, and the number depends on whether your car was built with a standard particulate filter or an activated-carbon one, as well as on trim and build date. The references below are aftermarket catalogue listings for this generation, grouped by brand; the carmaker's own number is not quoted in those listings, so check the genuine filter against your VIN if you want a guaranteed match. Carbon versions carry their own numbers and are listed separately.

Cabin filter, standard (aftermarket)	Mann CU3039-2, Mahle LA138, Valeo 715850, Filtron K1227-2x
Activated-carbon version (aftermarket)	Mahle LAK 138, Filtron K 1227A-2x, Mann CUK3039-2
Genuine (OE) number	Not quoted in the catalogue listings — the fitted filter varies by trim and build date, so order the genuine one against your VIN
Fitment notes	Standard and carbon filters have different numbers, and the right size depends on trim and build date. Check which type your car was built with before ordering.

Accuracy note: genuinely worth knowing: the filter's printed physical dimensions (length, width, depth) are the most reliable way to confirm fitment on a C4 Picasso if you're unsure of your exact model year, since the part is defined more by its housing size than by model name alone.

A Genuine, Real Mistake Worth Avoiding: Aerosol Sanitiser Can Kill the Fan — Citroen C4 Picasso Cabin Air Filter

If you're treating a musty smell with an aerosol AC sanitiser spray, this is worth knowing directly: one documented owner's experience saw the spray coat the blower fan in a sticky residue, which eventually caused the fan to become squeaky and then fail entirely, requiring replacement. Using these products sparingly, following the manufacturer's directions precisely rather than spraying liberally, and avoiding direct, sustained spraying into the intake where it can coat the fan itself, is worth doing rather than assuming more product means a more thorough clean.

A genuinely useful, free DIY test worth trying if you suspect a blocked drain: the cabin air filter housing has a drain that can become blocked, causing water to back up rather than draining away properly. Removing the interior trim near the drain hose and pouring water directly into it is a genuine, simple way to confirm whether it's actually blocked or broken — if water doesn't flow through freely, this is worth clearing before assuming a more complex leak source.

It's also worth checking the scuttle panel drain holes at the base of the windscreen, which can block with leaves and debris and cause rainwater to overflow directly into the ventilation air intake — this is genuinely more likely to happen specifically when the car is parked on a hill or slope.

Citroen C4 Picasso Cabin Air Filter: Easy to Forget, Easy to Fix

Of everything covered for the Citroen C4 Picasso, this is about as low-stakes mechanically as it gets — it doesn't touch how the car drives at all. Its only job is cabin air quality, which is exactly why owners tend to ignore it until something makes that hard to do.

Citroen C4 Picasso Cabin Air Filter: Watch: Replacing It

🎬 Watch: Citroen C4 Picasso Cabin filter replacement

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Citroen C4 Picasso Cabin Air Filter reference plate

Before you buy: filter size and whether your car uses a standard or activated-carbon filter varies by trim. Always confirm against your VIN before ordering.

Citroen C4 Picasso Cabin Air Filter: What It Does

On the Citroen C4 Picasso, this filter sits in the ventilation intake, not the engine bay, and cleans the air reaching the cabin — trapping dust, pollen, and on carbon-activated versions, some odours and pollutants too. The engine air filter is a completely different part, serving combustion rather than the cabin.

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Citroen C4 Picasso Cabin Air Filter: Warning Signs, DIY Difficulty & Aftermarket Advice

These are the same regardless of make or model — see our full Cabin Air Filter Guide for signs it needs changing, confirming fitment against your VIN, and choosing standard, carbon, or HEPA media.

More Citroen Cabin Air Filter

The same part, covered across other Citroen models.