2014 Citroen C4 1.6L Diesel · DF14 CBU

The most recent MOT, dated 23 October 2025, recorded a failure for a major exhaust‑emissions defect, the vehicle exceeding the statutory limit of 0.7 g km‑¹ for carbon monoxide. Apart from this, the test otherwise showed no further faults, and the previous recorded MOT in May 2017 was a clean pass with no advisories. The contrast between a clean pass twelve years ago and a single, significant emissions failure now suggests a maintenance trend that is beginning to deteriorate, rather than improving, and points to the need for immediate attention to the engine‑breathing system. At 326,585 miles the car has accumulated an average of roughly 27,200 miles per year, well above the typical UK usage pattern for a 2014 model. Such a high annual mileage accelerates wear on consumables and structural components; the drivetrain, suspension bushes and engine bearings will have experienced far more cycles than a lower‑mileage counterpart. The mileage figure also implies relatively short service intervals may have been missed, and the high mileage combined with the emissions failure raises the likelihood of worn piston rings, valve‑seal leakage or a deteriorating catalytic converter. A prospective buyer should focus the pre‑purchase inspection on the exhaust and engine management systems. Verify the condition of the catalytic converter for signs of blockage or internal collapse, and check the oxygen sensor and related wiring for corrosion or loose connections. On a test drive listen for a rich or lean exhaust note, rough idle, loss of power under load or excessive fuel consumption, all of which can herald the cause of the emissions breach. A post‑test‑drive emissions re‑check, preferably on a portable analyser, will confirm whether the fault is rectifiable by a fuel‑trim adjustment, sensor replacement or whether more invasive engine work is required. Given the vehicle’s age and mileage, the buyer should also examine the suspension for worn bushings, cracked coil springs or any clunking when traversing bumps, and inspect the brake discs for surface rust, scoring or uneven wear that could indicate binding calipers. Tyre sidewalls should be checked for age‑related cracking, as rubber degrades after six years regardless of tread depth. The 12‑volt battery, likely over a decade old, ought to be load‑tested, and all major fluid reservoirs—engine oil, coolant, brake fluid and power‑steering fluid—should be sampled for colour, level and signs of contamination, with a view to a full service if any fluid appears dark, milky or has a burnt smell. These checks will give a realistic picture of the car’s overall roadworthiness and the likely cost of bringing it back to a reliable, compliant state.