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Audi A4 vs Audi A6 s line 50 tfsi e quattro sa: reliability comparison

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

Audi A4
76%
MOT pass rate · 568,515 vehicles
Audi A6 s line 50 tfsi e quattro sa
93%
MOT pass rate · 1,113 vehicles
More reliable
Verdict: On MOT pass rate, the Audi A6 s line 50 tfsi e quattro sa is the more reliable of the two — 93% pass first time versus 76%. It's one signal among several; check the full breakdown below.

Head to head

Measure Audi A4 Audi A6 s line 50 tfsi e quattro sa
MOT pass rate 76% 93% ✓
MOT failure rate 24% 7% ✓
Faults & advisories per test 1.9 0.7 ✓
Dangerous-fault share 2% ✓ 7%
Average mileage 133,841 mi 59,135 mi
Sample size (vehicles) 568,515 1,113

Most common faults

Audi A4

  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 Rear Tyre worn close to the legal limit (4.1.E.1)
  4. Offside Rear Tyre worn close to the legal limit (4.1.E.1)
  5. Under-trays fitted obscuring some underside components
  6. Nearside Front Tyre worn close to legal limit/worn on edge (5.2.3 (e))

Audi A6 s line 50 tfsi e quattro sa

  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. Offside Rear Tyre worn close to legal limit/worn on edge (5.2.3 (e))
  4. Nearside Rear Tyre worn close to legal limit/worn on edge (5.2.3 (e))
  5. Windscreen damaged but not adversely affecting driver's view (3.2 (a) (i))
  6. Offside Rear Lower Coil spring mounting corroded but not seriously weakened (5.3.1 (b) (i))

Reliability FAQ

On MOT pass rate, the Audi A6 s line 50 tfsi e quattro sa is the more reliable of the two — 93% pass first time versus 76%. It's one signal among several; check the full breakdown below.

Full Audi A4 report Full Audi A6 s line 50 tfsi e quattro sa 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.