2021 Audi Q4 E-Tron S Line 40 — MOT failures & pass rate
Across 3,643 MOT tests analysed for the 2021 Audi Q4 E-Tron S Line 40, the most common recorded failure areas were tyres, lighting & signalling and visibility. Its pass rate of 89.7% was below the average for cars of a similar age (91.2%). Higher-mileage examples failed more often — 15.7% in the 60-90k group versus 9.1% in the 0-30k group.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 8.4% | 307 |
| 2 | Lighting & signalling | 1.5% | 56 |
| 3 | Visibility | 1.4% | 51 |
| 4 | Seat belts & restraints | 0.7% | 25 |
| 5 | Suspension | 0.5% | 20 |
| 6 | Other defects | 0.3% | 11 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Tread depth | 85 |
| 2 | Headlamp aim | 58 |
| 3 | Washers | 30 |
| 4 | SRS malfunction indicator lamp | 21 |
| 5 | Wipers | 21 |
| 6 | Registration plates | 16 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Tyres | 27.2% | 990 |
| 2 | Other defects | 8.2% | 298 |
| 3 | Suspension | 2.7% | 98 |
| 4 | Visibility | 2.4% | 88 |
| 5 | Brakes | 1.8% | 65 |
| 6 | Lighting & signalling | 0.3% | 10 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 0-30k | 1,532 | 9.1% |
| 30-60k | 1,821 | 10.7% |
| 60-90k | 262 | 15.7% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2023 | 31 | 9.7% |
| 2024 | 1,807 | 10.3% |
| 2025 | 1,805 | 10.3% |
What to check before buying a 2021 Q4 E-Tron S Line 40
Before buying a 2021 Audi Q4 E-Tron S Line 40, focus on the areas it most often fails on. Tyres accounted for 8.4% of tests for this year.
- Tyres (8.4% 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 (1.5% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Visibility (1.4% of tests): Wipers, washers, mirrors and screen damage — usually inexpensive, but check for chips in the driver's line of sight. Typical repair: £15–£150.
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 Q4 E-Tron S Line 40s pass their MOT?
89.7% of the 3,643 2021 Audi Q4 E-Tron S Line 40 MOT tests in this dataset passed — a 10.3% fail rate.
What is the most common MOT failure on a 2021 Audi Q4 E-Tron S Line 40?
Tyres, recorded in 8.4% of tests, followed by lighting & signalling (1.5%).
Does the 2021 Q4 E-Tron S Line 40 get worse with mileage?
Its MOT fail rate rises from 9.1% in the 0-30k band to 15.7% in the 60-90k band.
Methodology & source. Based on 3,643 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.