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Mercedes-benz A-class vs Mercedes-benz S 400 l amg line prem d 4m a: reliability comparison

MOT pass rates, common faults and mileage compared from real UK MOT data.

Mercedes-benz A-class
78%
MOT pass rate · 362,612 vehicles
Mercedes-benz S 400 l amg line prem d 4m a
93%
MOT pass rate · 5 vehicles
Verdict: On MOT pass rate the Mercedes-benz A-class (78%) and Mercedes-benz S 400 l amg line prem d 4m a (93%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.

Head to head

Measure Mercedes-benz A-class Mercedes-benz S 400 l amg line prem d 4m a
MOT pass rate 78% 93% ✓
MOT failure rate 22% 7% ✓
Faults & advisories per test 1.6 0.9 ✓
Dangerous-fault share 3% ✓ 7%
Average mileage 86,210 mi 43,125 mi
Sample size (vehicles) 362,612 5

Most common faults

Mercedes-benz A-class

  1. Nearside Front Tyre worn close to legal limit/worn on edge (5.2.3 (e))
  2. Offside Front Tyre worn close to legal limit/worn on edge (5.2.3 (e))
  3. Nearside Front Tyre worn close to the legal limit (4.1.E.1)
  4. Under-trays fitted obscuring some underside components
  5. Offside Front Tyre worn close to the legal limit (4.1.E.1)
  6. Offside Rear Tyre slightly damaged/cracking or perishing (5.2.3 (d) (ii))

Mercedes-benz S 400 l amg line prem d 4m a

  1. Offside Rear Tyre worn close to legal limit/worn on edge bald on edge (5.2.3 (e))
  2. Front Tyre worn close to legal limit/worn on edge 225/40/20 both sides worn on edge (5.2.3 (e))
  3. Front Brake pad(s) wearing thin worn 2mm (1.1.13 (a) (ii))
  4. Front Tyre has a cut but not deep enough to reach the ply or cords cuts on wall both sides 255/40r20 (5.2.3 (d) (i))
  5. Offside Windscreen damaged but not adversely affecting driver's view (3.2 (a) (i))
  6. Nearside Front Tyre has a cut but not deep enough to reach the ply or cords 255/40/20 (5.2.3 (d) (i))

Reliability FAQ

On MOT pass rate the Mercedes-benz A-class (78%) and Mercedes-benz S 400 l amg line prem d 4m a (93%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.

Full Mercedes-benz A-class report Full Mercedes-benz S 400 l amg line prem d 4m a report Most reliable cars

Pass rates are computed over completed (pass/fail) MOT tests. Reliability also depends on age, mileage and upkeep — see each model's page for the full picture.