Alternators are the most commonly claimed-for item under UK LCV warranties, according to data from Warranty Solutions Group (WSG).
The company said the finding was based on 1,000 extended warranty claims paid between July 2024 and June 2025.
Alternators were the subject of 5.35% of claims, with an average value of £506.78.
NOx sensors were second, with 4.51% of claims, worth £558.68 on average, while diesel injectors were third, at 3.67% (£613.29 average).
Completing the top ten were AdBlue injectors (2.75%, £311.45), DPFs (2.68%, £1,303.75), batteries (2.52%, £235.20), EGR valves (2.45%, £595.47), dual mass flywheels (1.83%, £943.48), turbochargers (1.83%, £872.89), and EGR coolers (1.76%, £850.98).
WSG head of commercial vehicle sales Mark Bobbins said: “What we’re seeing is a growing pattern: emissions-related components like NOx sensors, EGR valves, and AdBlue injectors are not just expensive to replace, they’re also failing more often. This isn’t just a technical issue – it’s a financial one.
“With environmental regulations tightening and vehicle systems becoming more complex, the cost of non-maintenance is rising fast. Proactive servicing and strong warranty support are no longer optional, they’re essential for managing risk and maintaining fleet uptime.
“In the current economic climate, one major repair can knock profitability off course. That’s why understanding which parts fail most, and planning accordingly, can make a measurable difference to a fleet’s bottom line. Our live claims data helps operators make smarter decisions about vehicle selection, servicing, and protection.”
