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Audi A6 vs Audi S4: reliability comparison

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

Audi A6
78%
MOT pass rate · 246,602 vehicles
Audi S4
80%
MOT pass rate · 2,068 vehicles
More reliable
Verdict: On MOT pass rate, the Audi S4 is the more reliable of the two — 80% pass first time versus 78%. It's one signal among several; check the full breakdown below.

Head to head

Measure Audi A6 Audi S4
MOT pass rate 78% 80% ✓
MOT failure rate 22% 20% ✓
Faults & advisories per test 1.7 1.6 ✓
Dangerous-fault share 2% 2%
Average mileage 136,441 mi 108,606 mi
Sample size (vehicles) 246,602 2,068

Most common faults

Audi A6

  1. Nearside Front Tyre worn close to the legal limit (4.1.E.1)
  2. Offside Front Tyre worn close to the legal limit (4.1.E.1)
  3. Nearside Front Tyre worn close to legal limit/worn on edge (5.2.3 (e))
  4. Offside Front Tyre worn close to legal limit/worn on edge (5.2.3 (e))
  5. Nearside Rear Tyre worn close to the legal limit (4.1.E.1)
  6. Offside Rear Tyre worn close to the legal limit (4.1.E.1)

Audi S4

  1. Oil leak, but not excessive (8.4.1 (a) (i))
  2. Nearside Rear Tyre worn close to the legal limit (4.1.E.1)
  3. Offside Rear Tyre worn close to the legal limit (4.1.E.1)
  4. Nearside Front Tyre worn close to the legal limit (4.1.E.1)
  5. Under-trays fitted obscuring some underside components
  6. Offside Front Tyre worn close to the legal limit (4.1.E.1)

Reliability FAQ

On MOT pass rate, the Audi S4 is the more reliable of the two — 80% pass first time versus 78%. It's one signal among several; check the full breakdown below.

Full Audi A6 report Full Audi S4 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.