2015 Ford Fiesta 1.0L Petrol · TH12 DAN

A cluster of significant structural and emissions defects surfaced on this Fiesta in early January 2026, breaking an otherwise uninterrupted run of clean passes dating back to 2023. The failure on 1 January 2026 cited a leaking exhaust flexi pipe, a lambda sensor reading outside specified limits after the second fast idle, and excessive wear on both nearside and offside rear axle swivel pins and bushes. A re-test just two days later on 7 January returned a pass with no defects recorded, meaning remedial work was carried out to address those majors before the vehicle was certified roadworthy. While the immediate rectification is reassuring, the simultaneous failure of both rear swivel pin assemblies alongside an exhaust integrity issue suggests a rear suspension geometry and emissions combination worth scrutinising closely, as the components involved are wear-prone and influenced by age, corrosion, and load history. The broader pattern is otherwise stable, with three consecutive passes between March 2023 and March 2025 carrying no advisories whatsoever, so the January 2026 episode represents an isolated but mechanically meaningful intervention rather than a chronic decline. At 57,657 miles across approximately eleven years of service, this Fiesta has accumulated mileage at around 5,200 miles per year, which is considerably below the typical annual average for a vehicle of this type and age. Such low usage tends to preserve major drivetrain components but can accelerate degradation of items that suffer from prolonged stationary exposure, including brake discs corroding on their friction surfaces, underbody corrosion taking hold through lack of regular washing-off of winter salts, and rubber suspension components stiffening or perishing through inactivity. There are no gaps in the testing history that suggest an extended off-road period, and the mileage progression between annual tests appears consistent with steady, modest use. Mechanically, this profile argues for very close inspection of the braking system for corroded or scored discs, the exhaust system for underfloor corrosion around joints and mounting points, and the suspension linkages for perished bushes that may not have been exercised sufficiently to reveal play before MOT inspection. Given the rear axle swivel pins and bushes were flagged on both sides, a prospective buyer should focus their attention squarely on the back end during any physical inspection and test drive. With the vehicle unloaded on level ground, rock each rear wheel firmly in a top-and-bottom motion at the wheel itself to feel for any play, knocking, or clonking transmitting through to the hub assembly, which would indicate the replacement bushes have settled, worn prematurely, or that adjacent components such as the rear beam mountings and trailing arm bushes may also be approaching the end of their service life. Listen carefully for any dull metallic thuds or creaks from the rear suspension over speed humps, pothole edges, and uneven road surfaces, as these are characteristic of worn pivot bushes and swivel pins working loosely within their housings. Check that the rear wheels sit evenly within their arches with no obvious camber variance or uneven tracking, and visually inspect the underside for any grease staining around the bush housings which could point to fresh lubricant masking ongoing wear. The exhaust flexi pipe failure and lambda sensor out-of-range reading together suggest the upstream catalyst and oxygen sensing system should be validated during a test drive. After a thorough warm-up, observe whether the engine idles smoothly with no flat spots, hesitation, or an illuminated emissions-related dashboard warning, and confirm that exhaust noise remains muted with no ticking, hissing, or chuffing from beneath the engine or near the catalyst area that would indicate the new joint is already compromised. Because the lambda reading was specifically out of limits on the second fast idle, a diagnostic scan reading live sensor voltages at operating temperature would be highly advisable, as a borderline catalytic converter may still produce acceptable gas analysis results in the short term but deteriorate rapidly. Finally, inspect the underside carefully for any surface corrosion on the rear axle beam, subframe mounting points, and brake pipe runs along the chassis, as the low annual mileage and the age of the vehicle make these areas particularly susceptible to the kind of underfloor oxidation that could otherwise develop unnoticed between MOT tests.