2021 Audi A3 S Line 1 35 S-A — MOT failures & pass rate

Across 765 MOT tests analysed for the 2021 Audi A3 S Line 1 35 S-A, the most common recorded failure areas were tyres, lighting & signalling and brakes. Its pass rate of 88.9% was below the average for cars of a similar age (91.3%). Higher-mileage examples failed more often — 20.0% in the 60-90k group versus 8.3% in the 0-30k group.

Pass rate

765

MOT tests analysed

11.1%

Fail rate

worse than

vs cars of similar age

3.4

Avg age at test (yrs)

How it compares

Fail rate for this model-year against the segment and national averages for cars of a similar age.

Top failure categories

Most common MOT failure areas — 2021 Audi A3 S Line 1 35 S-A
#	Category	% of tests affected	Tests
1	Tyres	8.1%	62
2	Lighting & signalling	1.3%	10
3	Brakes	1.3%	10
4	Emissions & environmental	0.9%	7
5	Seat belts & restraints	0.8%	6
6	Suspension	0.7%	5

Percentage of tests with at least one failure recorded in each category.

Most common specific failures

The exact components most often recorded as failures — more specific than the categories above.

Most frequently recorded failure items — 2021 Audi A3 S Line 1 35 S-A
#	Failure item	Times recorded
1	Tread depth	17
2	Headlamp aim	15
3	Brake pads	9
4	Registration plates	8
5	Malfunction indicator lamp	7
6	SRS malfunction indicator lamp	4

Top advisory categories

Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.

Most common MOT advisories — 2021 Audi A3 S Line 1 35 S-A
#	Category	% of tests with advisory	Tests
1	Tyres	22.5%	172
2	Brakes	12.0%	92
3	Other defects	8.0%	61
4	Suspension	3.9%	30
5	Visibility	3.1%	24
6	Road wheels	1.3%	10

Failure rate by mileage

Higher-mileage cars tend to fail more — often the most useful guide to real condition.

MOT fail rate by recorded mileage band.

Fail rate by recorded mileage — 2021 A3 S Line 1 35 S-A
Mileage band	Tests	Fail rate
0-30k	290	8.3%
30-60k	386	10.9%
60-90k	85	20.0%

Failure rate by age

How this model-year's MOT fail rate climbs as the cars get older.

Trend over time

Fail rate by dataset year — 2021 A3 S Line 1 35 S-A
Dataset year	Tests	Fail rate
2024	367	9.5%
2025	370	13.5%

What to check before buying a 2021 A3 S Line 1 35 S-A

Before buying a 2021 Audi A3 S Line 1 35 S-A, focus on the areas it most often fails on. Tyres accounted for 8.1% of tests for this year.

Tyres (8.1% of tests): Usually a quick, known-cost fix, but check tread, age and uneven wear (which can hint at alignment or suspension issues). Typical repair: £50–£120 per tyre.
Lighting & signalling (1.3% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
Brakes (1.3% of tests): Pads/discs are routine wear; binding, imbalance or corroded pipes are more serious — test for pulling under braking. Typical repair: £100–£350 per axle.

Repair costs are rough UK ballpark ranges to set expectations, not quotes — actual prices vary widely by car, parts and garage.

Frequently asked questions

How many 2021 Audi A3 S Line 1 35 S-As pass their MOT?

88.9% of the 765 2021 Audi A3 S Line 1 35 S-A MOT tests in this dataset passed — a 11.1% fail rate.

What is the most common MOT failure on a 2021 Audi A3 S Line 1 35 S-A?

Tyres, recorded in 8.1% of tests, followed by lighting & signalling (1.3%).

Does the 2021 A3 S Line 1 35 S-A get worse with mileage?

Its MOT fail rate rises from 8.3% in the 0-30k band to 20.0% in the 60-90k band.

Methodology & source. Based on 765 MOT tests. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-01. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.