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Mercedes-benz A-class vs Mercedes-benz S320: 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 S320
83%
MOT pass rate · 10 vehicles
Verdict: On MOT pass rate the Mercedes-benz A-class (78%) and Mercedes-benz S320 (83%) 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 S320
MOT pass rate 78% 83% ✓
MOT failure rate 22% 17% ✓
Faults & advisories per test 1.6 1.1 ✓
Dangerous-fault share 3% 1% ✓
Average mileage 86,210 mi 105,735 mi
Sample size (vehicles) 362,612 10

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 S320

  1. Nearside Side repeater slightly discoloured (4.4.3 (a))
  2. Under-trays fitted obscuring some underside components
  3. Offside Front Direction indicator slightly discoloured (4.4.3 (a))
  4. Nearside Front Direction indicator slightly discoloured (4.4.3 (a))
  5. Nearside Front Lower Suspension arm ball joint has slight play (5.3.4 (a) (i))
  6. Nearside Rear Tyre worn close to legal limit/worn on edge (5.2.3 (e))

Reliability FAQ

On MOT pass rate the Mercedes-benz A-class (78%) and Mercedes-benz S320 (83%) 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 S320 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.