2016 Vauxhall Insignia 1.4L Petrol · DP16 YAO

A decade-old Vauxhall Insignia presenting with an emissions-related failure at the most recent test on 16 April 2026 introduces a specific mechanical concern into an otherwise largely clean roadworthiness record. The Lambda probe reading falling outside the specified limits after the second fast idle points to either a deteriorated exhaust gas oxygen sensor, a catalytic converter operating below efficiency, or a fuelling irregularity that has disturbed the air-fuel ratio the sensor is reading. It is worth noting the same date also carries a clean pass entry, indicating the failure was addressed and a retest carried out within hours or days, with no further advisories recorded. Earlier test results show another isolated failure on 26 April 2022 concerning an inoperative registration plate lamp and a non-functioning nearside front headlamp on dipped beam, both minor electrical items rather than structural or powertrain concerns. Aside from these two isolated events, the vehicle has passed each annual test from 2021 onwards with no recorded defects, meaning the broader structural and safety components have not been flagged as concerning by DVSA examiners across the period. The recorded mileage of 66,401 miles across approximately ten years of use equates to an average of around 6,640 miles per year, which sits broadly in line with typical annual mileage for a vehicle of this age and type. There are no extended gaps in the testing record that would suggest a prolonged period off the road, and the consistent year-on-year attendance at MOT testing implies regular use, which from a mechanical perspective is generally favourable for components that suffer when left standing, such as the braking system, suspension bushes, and exhaust mounting rubbers. A usage pattern of this kind typically results in moderate rather than severe wear on consumables, though the 1.8 litre diesel or petrol engine fitted to this generation of Insignia will have accumulated ten years of general service demands on items such as belts, coolant, and oil seals regardless of annual mileage. Given the 2026 Lambda reading failure, a prospective buyer should focus diagnostic attention on the exhaust and emissions system, particularly the upstream oxygen sensor condition, the integrity and efficiency of the catalytic converter, and any stored fault codes relating to fuel trim or mixture imbalance that a generic OBD-II scan could reveal. Listen on the test drive for any irregular idling, hunting revs, or hesitation under throttle that might indicate the fuelling issue has not been fully resolved, and inspect the exhaust for any rattle suggesting internal catalytic converter breakdown. The 2022 headlamp and registration plate lamp failure, while minor, serves as a reminder to verify all exterior lighting operates correctly, as corrosion within lamp housings or failing bulb holders is a common age-related issue on this model. Beyond the directly flagged items, attention should be paid to suspension components typical of the Insignia at this mileage, including front wishbone bushes, anti-roll bar drop links, and coil spring seats, listening for knocks or clonks over uneven road surfaces and feeling for vagueness through the steering. The braking system should be tested for pulling under firm application and for any judder through the pedal, which would indicate warped front discs, a common wear item on a vehicle of this age and mileage. A thorough underbody inspection for corrosion, particularly around the rear wheel arches, subframe mounting points, and brake pipe runs, is advisable given the vehicle's age, and any signs of fresh underseal applied over bubbling paint should be questioned as it can mask developing structural issues that the MOT inspection has not yet identified.