Hi, I have a 2018 Volvo S90 which has just had a major failure on it's NCT (Irl equivalent of MOT) because the track rod ends are worn on one side. Any ideas on what could have caused this?

There is a left and a right track rod and each rod has an inner and outer joint ('end'). Normally it is the outer end that wears fastest (subjected to most articulation). Its probably just wear and tear, accelerated if the protective rubber boot is damaged or deteriorated. Normally quite cheap and easy to replace.

OK Thanks for reply. Any idea how much it would cost? I was surprised as car only has about 50k miles and I just had a major service....

An outer track rod end for this car probably costs in the region £20 - 50, or a lot more if you buy from the dealer. Plus about 30 minutes labour to fit. You may well need to have the front wheel alignment set on completion of the job.

This would be one of the 'Geely Volvos' - designed with the company under Chinese ownership. My impression is that they are not built solid like the old Volvos.