2021 Audi A4 S Line 35 TDI Mhev S-A 2.0L Heavy oil · HY61 ARY

The most recent MOT recorded on 14 May 2025 was a pass with no defects noted, following a failed test two days earlier that also listed no specific faults. The absence of recorded deficiencies on either occasion suggests that the vehicle has been maintained to a level that satisfies the statutory safety and emissions checks, and the progression from a failure to a pass within a short interval indicates that any administrative or minor issues were promptly rectified. Overall the maintenance trend appears stable rather than deteriorating. At 49,074 miles the 2021 Audi A4 S line has logged roughly 9,800 miles per annum, which sits squarely within the normal usage envelope for a five‑year‑old executive saloon. There are no obvious gaps in the mileage record that would point to prolonged periods of inactivity, nor is there evidence of unusually high annual mileage that would accelerate wear on high‑frequency components such as the clutch, brake pads or tyre tread. Consequently the mileage alone does not raise any red flags, but it does mean that consumables are likely approaching the mid‑point of their service lives. For a vehicle of this age and mileage the buyer should give particular attention to age‑related degradation. Inspect the tyre sidewalls for cracking, dry rot or any signs of perishing, especially if the car has spent time standing in damp conditions; tread depth should be uniform across the wheel set and meet the legal minimum. The 12‑volt lead‑acid battery, now six years old, should be load‑tested and examined for electrolyte level or swelling, as a weakened battery can cause intermittent electronic gremlins in the MHEV system. Verify that the brake discs are free of excessive rust, scoring or glazing and that the pads retain sufficient thickness; any uneven wear could indicate sticking calipers or warped rotors, which would manifest as pulsation or shudder when braking. Examine the suspension bushings, control arm joints and the rear sub‑frame for any creaking or clunking during a low‑speed manoeuvre, as rubber components can harden and lose compliance after several years of service. Given the diesel‑plus‑mild‑hybrid powertrain, it is prudent to confirm that the diesel particulate filter (DPF) regeneration history is clean and that there are no warning lights for exhaust emissions; a clogged DPF can cause loss of power and increased fuel consumption. Check that the oil and coolant have been changed at the manufacturer‑recommended intervals, as time‑based fluid degradation can occur even with modest mileage. Finally, request a full service book stamp and any recent diagnostic read‑outs to ensure that the electronic control units, especially the MHEV battery management system, are operating within normal parameters and that no latent fault codes have been logged. These checks will give a comprehensive picture of the car’s mechanical and electronic health before committing to purchase.