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Audi A6 vs Audi S4 quattro auto: 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 quattro auto
82%
MOT pass rate · 49 vehicles
Verdict: On MOT pass rate the Audi A6 (78%) and Audi S4 quattro auto (82%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.

Head to head

Measure Audi A6 Audi S4 quattro auto
MOT pass rate 78% 82% ✓
MOT failure rate 22% 18% ✓
Faults & advisories per test 1.7 0.6 ✓
Dangerous-fault share 2% 2%
Average mileage 136,441 mi 114,211 mi
Sample size (vehicles) 246,602 49

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 quattro auto

  1. Central Front Upper Oil leak, but not excessive (8.4.1 (a) (i))
  2. Nearside Front Lower Suspension arm pin or bush worn but not resulting in excessive movement (5.3.4 (a) (i))
  3. Offside Front Lower Suspension arm pin or bush worn but not resulting in excessive movement (5.3.4 (a) (i))
  4. Offside Front Tyre worn close to the legal limit (4.1.E.1)
  5. Offside Rear Tyre worn close to the legal limit (4.1.E.1)
  6. Oil leak, but not excessive (8.4.1 (a) (i))

Reliability FAQ

On MOT pass rate the Audi A6 (78%) and Audi S4 quattro auto (82%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.

Full Audi A6 report Full Audi S4 quattro auto 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.