Audi S4 B9 (2016-2024) reliability
Audi S4 B9 built around 2020: about average at the MOT
Audi S4 B9 models built around 2020 fail their MOT a little less often than similar cars the same age.
Looking at an Audi S4 B9?
Enter its number plate to see its full MOT history, risk rating and running costs.
Key figure
9% of MOT tests on Audi S4 B9 models built around 2020 ended in a fail (retests included), against 12% for similar cars the same age.
Most common issue
The most common MOT issue on Audi S4 B9 models built around 2020 involves the tyres.
Based on 1,271 tests of S4 models registered 2016-2024.
About 1 in 12 diesel S4 cars registered in 2022 (7.6%) failed their first MOT.
Based on 172 first MOTs (DVSA MOT results, 2025).
About 1 in 40 S4 B9 MOTs (2.3%) failed and still hadn't passed 3 days later. That's for cars built around 2020 (5 years old), all fuels combined.
Based on 611 tests (DVSA MOT results, 2025), a small sample, so the figure is likely between 1.4% and 3.8%. A fail that passed a retest within 3 days, even the same day, isn't counted. Nor is a fail with no later MOT on record.
About 1 in 25 S4 B9 MOTs (4.3%) found at least one dangerous defect. These are cars built around 2020 (5 years old).
Based on 611 tests (DVSA MOT results, 2025), a small sample, so the figure is likely between 2.9% and 6.2%. Dangerous is the most serious grade an MOT gives: a direct risk to road safety.
B9 fail rate by age
Fail rate is the share of MOT tests that ended in a fail. Retests count as tests. How we count fail rates Build years are worked out from age, so they are approximate. Tests counted are 2025 MOTs. Highest fail rate at 6 years old.
How the S4 B9 compares
At each age below, see how the S4 B9 holds up against other cars the same age. The averages combine all fuel types.
Based on 119,144 tests across 23 Audi models, built around 2020 (5 years old).
Fail rate is the share of MOT tests that ended in a fail. Retests count as tests. How we count fail rates Build years are worked out from age, so they are approximate. Tests counted are 2025 MOTs.
What to check before viewing
The model's most common MOT issues, turned into things you can ask about or look for.
Brake discs
High priorityAsk for the date and mileage of the last disc replacement; visually check for a deep wear lip and rust pitting on each disc.
Brake pads
High priorityAsk when the pads were last replaced and check the warning-light history.
Tyres
Worth checkingCheck tread depth across the full width on all four; uneven wear suggests alignment or suspension issues.
Suspension springs
Worth checkingCheck ride height is even side-to-side and look for cracked or rusted coils.
Vehicle-specific check
Worth checkingCheck the car’s number plate on MOT Wise to see its own MOT history and any recalls for its build years.
Other saloons to compare
Other saloons, with each one's figures taken at the same age as the S4 B9.
- 1
Tesla Model 3
Same body type, tested at the same age
- Fail rate
- 15.9%
- Fail, no pass in 3 days
- 5.1%
- Dangerous
- 9.5%
No clear edge over the Audi S4 B9 on these figures.
21,865 MOT tests on cars built around 2020
- 2
Mazda 6
Same body type, tested at the same age
- Fail rate
- 10.9%
- Fail, no pass in 3 days
- 1.3%
- Dangerous
- 4.2%
- Still registered at 10 years
- 79.1%
Fewer fails still not passed 3 days later: 1.3%, against 2.3% for the Audi S4 B9.
5 critical recall campaigns matching this model/build period.
2,568 MOT tests on cars built around 2020
- 3
Volvo S90
Same body type, tested at the same age
- Fail rate
- 10.3%
- Fail, no pass in 3 days
- 1.8%
- Dangerous
- 6.3%
No clear edge over the Audi S4 B9 on these figures.
2 critical recall campaigns matching this model/build period.
1,581 MOT tests on cars built around 2020
- 4
Alfa Romeo Giulia
Same body type, tested at the same age
- Fail rate
- 10.2%
- Fail, no pass in 3 days
- 2.5%
- Dangerous
- 4.5%
No clear edge over the Audi S4 B9 on these figures.
1,198 MOT tests on cars built around 2020
- Fail rate
- = the share of MOT tests that ended in a fail. Retests count as tests.
- Fail, no pass in 3 days
- = the share of MOT tests that failed and still hadn't passed 3 days later. A fail that passed a retest within 3 days, even the same day, isn't counted.
- Dangerous
- = the share of MOT tests where the tester marked a fault as dangerous. It is against the law to drive the car until it is fixed.
- Still registered at 10 years
- = the share of cars still registered (taxed or declared off the road) 10 years after they were first registered.
Recall context
DVSA's recall list has no recalls filed under the Audi S4 name. For the exact car, check with the maker or GOV.UK's recall checker.
How S4 B9 cars have aged
How S4 B9 cars have aged
How fail rates have changed as these cars got older. Each line follows cars first registered in about the same year across several years of MOT data. Not a prediction for any one car.
Some lines cover only a year or two, so read this as a rough guide.
B9 variants compared
S4 B9 variants built around 2020
The fail rate for each S4 B9 variant, grouped by fuel. Each row counts fails per MOT test, the same way as the main fail rate chart.
Diesel
- S4 BLACK EDITION TDI QUATTRO A9.4%404 tests
- S4 TDI QUATTRO AUTO7.9%203 tests
Most common issues on Audi S4 models of this age
This list covers every Audi S4 built around 2020, whichever generation it is. We don't have a defect list for the B9 on its own.
Most common advisories and fails
In order of the share of MOT tests that recorded each one
- 113.9%Advisory
Tyre worn close to the legal limit or worn on the edge
- 27.9%Advisory
Brake pads wearing thin
- 37.2%Advisory
Brake disc worn, pitted or scored, but not seriously weakened
- 45.4%Advisory
Coil spring corroded
- 55.2%Advisory
Tyre slightly damaged, cracking or perishing
Based on 611 tests
Looking at an Audi S4 B9?
Enter its number plate to see its full MOT history, risk rating and running costs.
Frequently asked questions
Built around 2020 (5 years old), the Audi S4 B9 (2016-2024) fails MOTs noticeably less often than typical for this age. This is based on 611 5-year-old MOT tests from DVSA data. Each retest counts as a test.