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Mercedes-benz 300 s vs Mercedes-benz A-class: reliability comparison

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

Mercedes-benz 300 s
90%
MOT pass rate · 5 vehicles
Mercedes-benz A-class
78%
MOT pass rate · 362,612 vehicles
Verdict: On MOT pass rate the Mercedes-benz 300 s (90%) and Mercedes-benz A-class (78%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.

Head to head

Measure Mercedes-benz 300 s Mercedes-benz A-class
MOT pass rate 90% ✓ 78%
MOT failure rate 10% ✓ 22%
Faults & advisories per test 1.0 ✓ 1.6
Dangerous-fault share 10% 3% ✓
Average mileage 102,880 mi 86,210 mi
Sample size (vehicles) 5 362,612

Most common faults

Mercedes-benz 300 s

  1. Exhaust emits blue smoke during acceleration (8.2.1.2 (g))
  2. under trays and engine covers fitted obscuring view of certain testable components
  3. All tyres starting to perish
  4. Hazard warning switch faulty (4.4.2 (a) (i))
  5. Suspension system inoperative (5.3.5 (a))
  6. Front Tyre slightly damaged/cracking or perishing BOTH (5.2.3 (d) (ii))

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))

Reliability FAQ

On MOT pass rate the Mercedes-benz 300 s (90%) and Mercedes-benz A-class (78%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.

Full Mercedes-benz 300 s report Full Mercedes-benz A-class 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.