CARMOTIQ Model Research Report
Audi A4
2016–2021
Unlike a registration check, this report analyses how thousands of similar Audi A4 models have performed at MOT over time—not just one vehicle.
This report analyses 478,423 official UK MOT tests and more than 581,693 recorded defect notes for Audi A4 models first registered between 2016 and 2021. It reveals common faults, MOT pass rates and maintenance trends to help you research the model before you buy.
Report Dataset
- Official UK DVSA MOT tests analysed
- 478,423
- Recorded defect notes
- 581,693
- Registration era
- 2016–2021
- Coverage
- United Kingdom
- Snapshot
- 23 July 2026
- Research method
- Aggregated model-level MOT analysis
MOT pass rate
86.5%
of MOT tests passed
MOT tests analysed
478,423
Defect notes recorded
581,693
Key Findings
Audi A4 (2016–2021)
- 86.5% MOT pass rate across 478,423 tests.
- 62% of recorded defect notes relate to owner maintenance.
- Tyres account for the largest volume of recorded MOT issues.
- Engine management (MIL) warnings are the most common recurring systemic issue.
- Headlamp alignment appears throughout the vehicle's life, from low to higher mileages.
Audi A4 Research Summary
Based on over 478,423 official UK MOT tests, Audi A4 models registered between 2016 and 2021 achieve a strong 86.5% MOT pass rate.
The majority of recorded MOT defects relate to routine owner maintenance, with tyres, dampers and lighting accounting for most common faults seen on used examples in this age band.
Recurring systemic faults occur far less frequently, although engine management warning lamp (MIL) defects appear consistently across the dataset.
Overall, the data suggests that this generation of Audi A4 is more likely to fail MOT due to maintenance items than widespread design faults, making service history and routine upkeep particularly important when buying used. Shoppers comparing a used Audi A4 should treat this research summary as model-level context before inspecting any individual car.
What this doesn't tell you
This report describes model-level MOT trends, not the condition of any individual vehicle.
Two identical Audi A4 models can have very different maintenance histories.
Use this report to understand common patterns before inspecting a specific car.
How we classify MOT faults
We group recorded DVSA defect wording into four research categories to help identify whether issues are more likely to reflect routine maintenance, expected wear, recurring model patterns or miscellaneous inspection outcomes.
- Owner maintenance
- Defects often linked to day-to-day upkeep — for example tyres, lamps, washers and other items a careful owner can usually prevent or fix promptly.
- Wear & tear
- Age- and mileage-related deterioration that accumulates with normal use, even when a car has been looked after.
- Systemic
- Recurring wording and patterns that appear across the model fleet and may point to design, component or known-model tendencies rather than one careless owner.
- Other
- Inspection outcomes that do not sit cleanly in the three groups above, including mixed or less classifiable defect notes.
How MOT failures break down
Share of recorded defect notes by category for Audi A4 in this age band (not MOT tests and not number of vehicles).
- Owner maintenance
61.9% · 359,821
defect notes
- Wear & tear
16.1% · 93,721
defect notes
- Systemic
2.2% · 13,071
defect notes
- Other
19.8% · 115,080
defect notes
Severity mix
How those defect notes were graded — advisory, minor, major or dangerous — summed across categories for this model band.
Advisory
470,042
defect notes
Minor
21,046
defect notes
Major
56,071
defect notes
Dangerous
34,534
defect notes
Most Common Owner-Maintenance Faults
DVSA wording grouped as owner maintenance for this model and age band.
Tyre worn close to legal limit/worn on edge
- Recorded
- 155,195 MOT defect notes
- DVSA code
- 5.2.3 (e)
What it means
Tread is close to (or at) the legal minimum, or wear is concentrated on an edge. That often points to alignment, pressure or suspension issues as well as simple age.
Why it happens
Under-inflation, poor alignment, aggressive driving or simply delayed replacement push tread below a safe/legal profile.
Buyer tip
Measure tread across the full width, check tyre age (DOT date) and look for uneven inner-edge wear.
Severity
Usually maintenance related
Shock absorbers has light misting of oil
- Recorded
- 9,673 MOT defect notes
- DVSA code
- 5.3.2 (b)
What it means
A damper mounting bush is worn, which can cause knocks, vague handling and accelerated tyre wear.
Why it happens
Rubber bushes harden and tear with age, road salt and repeated suspension movement.
Buyer tip
Listen for clunks over speed bumps and have a mechanic check top mounts and lower bushes.
Severity
Usually maintenance related
Headlamp aim too low
- Recorded
- 5,994 MOT defect notes
- DVSA code
- 4.1.2 (a)
What it means
This MOT defect usually indicates incorrect headlamp alignment following adjustment, suspension movement or repair work.
Why it happens
Aim drifts after suspension work, bumper repairs, bulb changes or simply from road vibration over time.
Buyer tip
Check beam alignment during inspection and ask whether the lamps were aimed after any recent suspension or bodywork.
Severity
Usually maintenance related
Windscreen washer not working
- Recorded
- 2,501 MOT defect notes
- DVSA code
- 3.5 (a)
What it means
Washer jets are not delivering fluid. Testers need a clear screen; empty reservoirs, blocked jets or failed pumps are common.
Why it happens
Empty bottles, frozen/blocked jets, split pipes or a failed pump stop fluid reaching the screen.
Buyer tip
Top up fluid, test the jets on the driveway, and check for cracked bottles or split pipes in the engine bay.
Severity
Usually maintenance related
Tyre pressure monitoring system malfunctioning or obviously inoperative
- Recorded
- 1,715 MOT defect notes
- DVSA code
- 5.2.3 (h)
What it means
The tyre pressure monitoring system is reporting a fault or is clearly not working, so you may not get a dashboard warning of under-inflation.
Why it happens
Flat battery sensors after tyre changes, damaged valves or control-module faults are common.
Buyer tip
Confirm whether sensors need replacing after recent tyre or wheel work, and check pressures manually anyway.
Severity
Usually maintenance related
Supplementary restraint system warning lamp indicates a fault
- Recorded
- 1,211 MOT defect notes
- DVSA code
- 7.1.6 (a)
What it means
The airbag/SRS warning lamp indicates a fault. Restraint systems may not deploy correctly in a collision.
Why it happens
Clock-spring, sensor or module faults — sometimes after prior accident repairs — set SRS warnings.
Buyer tip
Require a specialist SRS diagnosis — do not accept a bulb removed or lamp covered up.
Severity
Usually maintenance related
Shock absorbers has a slightly worn bush
- Recorded
- 425 MOT defect notes
- DVSA code
- 5.3.2 (c)
What it means
A damper mounting bush is worn, which can cause knocks, vague handling and accelerated tyre wear.
Why it happens
Rubber bushes harden and tear with age, road salt and repeated suspension movement.
Buyer tip
Listen for clunks over speed bumps and have a mechanic check top mounts and lower bushes.
Severity
Usually maintenance related
Tyre not fitted in accordance with side wall instructions
- Recorded
- 292 MOT defect notes
- DVSA code
- 5.2.3 (i)
What it means
A tyre is fitted against its sidewall instructions (for example direction of rotation or inside/outside face).
Why it happens
Fitting errors at tyre change — directionals or asymmetric tyres mounted the wrong way round.
Buyer tip
Ask a tyre fitter to confirm orientation marks before you accept the car.
Severity
Usually maintenance related
Most Common Wear & Tear Faults
DVSA wording grouped as wear and tear for this model and age band.
Shock absorbers has an excessively worn bush
- Recorded
- 22 MOT defect notes
- DVSA code
- 5.3.2 (c)
What it means
A damper mounting bush is worn, which can cause knocks, vague handling and accelerated tyre wear.
Why it happens
Rubber bushes harden and tear with age, road salt and repeated suspension movement.
Buyer tip
Listen for clunks over speed bumps and have a mechanic check top mounts and lower bushes.
Severity
Usually wear related
Suspension component leaking rearbush
- Recorded
- 6 MOT defect notes
- DVSA code
- 5.3.5 (c)
What it means
A hydraulic suspension bush or related component is leaking fluid, which can change geometry and ride quality.
Why it happens
Hydraulic bush membranes split with age, leaking fluid and softening the mount.
Buyer tip
Look under the car for damp bushes and ask for specialist inspection on air/hydraulic systems.
Severity
Usually wear related
Service brake excessively binding Wheel bearing not tested
- Recorded
- 3 MOT defect notes
- DVSA code
- 1.2.1 (f)
What it means
Service brake performance could not be fully verified, or a brake is binding/fluctuating. That often points to worn discs, seized calipers or hub issues.
Why it happens
Seized caliper slides, worn discs or contaminated friction material upset brake balance.
Buyer tip
Insist on a road test and a proper brake inspection; unresolved binding can destroy pads and hubs.
Severity
Usually wear related
Brake pedal wearing smooth anti-slip rubber worn on edge
- Recorded
- 2 MOT defect notes
- DVSA code
- 1.1.2 (c)
What it means
The brake pedal rubber is worn smooth, reducing grip for your foot in the wet.
Why it happens
The pedal rubber wears through with daily use and is often left until an MOT flags it.
Buyer tip
A new pedal rubber is inexpensive — treat smooth pedals as a quick owner-maintenance fix.
Severity
Usually wear related
Emissions unable to be completed due to exhaust leak
- Recorded
- 2 MOT defect notes
- DVSA code
- 8.2.2.2 (e)
What it means
Emissions could not be completed cleanly, or a leak is likely to upset the reading. Common causes include exhaust leaks, misfires, DPF issues or an engine that will not idle correctly.
Why it happens
Leaks before the sample point, misfires, DPF problems or unstable idle prevent a valid emissions result.
Buyer tip
Listen for blow-by at joints, check for recent exhaust/DPF work, and avoid cars that need “easier” emissions excuses.
Severity
Usually wear related
Brake performance unable to be tested Due to worn brakes
- Recorded
- 2 MOT defect notes
- DVSA code
- 1.2.1 (g)
What it means
Service brake performance could not be fully verified, or a brake is binding/fluctuating. That often points to worn discs, seized calipers or hub issues.
Why it happens
Seized caliper slides, worn discs or contaminated friction material upset brake balance.
Buyer tip
Insist on a road test and a proper brake inspection; unresolved binding can destroy pads and hubs.
Severity
Usually wear related
Exhaust emissions likely to be affected by an exhaust leak sign of leak gas around dpf and turbo
- Recorded
- 2 MOT defect notes
- DVSA code
- 8.2.2.1 (b)
What it means
Emissions could not be completed cleanly, or a leak is likely to upset the reading. Common causes include exhaust leaks, misfires, DPF issues or an engine that will not idle correctly.
Why it happens
Leaks before the sample point, misfires, DPF problems or unstable idle prevent a valid emissions result.
Buyer tip
Listen for blow-by at joints, check for recent exhaust/DPF work, and avoid cars that need “easier” emissions excuses.
Severity
Usually wear related
Exhaust emissions likely to be affected by an exhaust leak
- Recorded
- 1 MOT defect notes
- DVSA code
- 8.2.1.1 (b)
What it means
Emissions could not be completed cleanly, or a leak is likely to upset the reading. Common causes include exhaust leaks, misfires, DPF issues or an engine that will not idle correctly.
Why it happens
Leaks before the sample point, misfires, DPF problems or unstable idle prevent a valid emissions result.
Buyer tip
Listen for blow-by at joints, check for recent exhaust/DPF work, and avoid cars that need “easier” emissions excuses.
Severity
Usually wear related
Most Common Systemic Faults
DVSA wording grouped as systemic patterns for this model and age band.
Engine MIL inoperative or indicates a malfunction
- Recorded
- 2,632 MOT defect notes
- DVSA code
- 8.2.2.2 (g)
What it means
The engine management warning lamp is on or not working. Stored faults can affect emissions, drivability and future MOT results.
Why it happens
Sensors, emissions equipment or wiring faults store codes that illuminate the MIL.
Buyer tip
Ask for a diagnostic printout and proof that the underlying fault — not just the lamp — was fixed.
Severity
Often a recurring model pattern
Engine MIL inoperative or indicates a malfunction
- Recorded
- 1,667 MOT defect notes
- DVSA code
- 8.2.1.2 (h)
What it means
The engine management warning lamp is on or not working. Stored faults can affect emissions, drivability and future MOT results.
Why it happens
Sensors, emissions equipment or wiring faults store codes that illuminate the MIL.
Buyer tip
Ask for a diagnostic printout and proof that the underlying fault — not just the lamp — was fixed.
Severity
Often a recurring model pattern
Brake pipe excessively corroded
- Recorded
- 175 MOT defect notes
- DVSA code
- 1.1.11 (c)
What it means
A brake pipe is damaged or heavily corroded. Pipe failure can cause sudden loss of braking effort.
Why it happens
Road salt, stone chips and age corrode metal pipes, especially along the underbody.
Buyer tip
Inspect metal pipes along the underbody and near calipers; corroded pipes should be replaced before you rely on the car.
Severity
Often a recurring model pattern
Registration plate deteriorated but not likely to be misread cracked
- Recorded
- 60 MOT defect notes
- DVSA code
- 0.1 (b)
What it means
The number plate is cracked, deteriorated or hard to read. Plates must remain legible and securely fitted.
Why it happens
Age, stone chips, poor replacements or mounts that flex crack or fade plates.
Buyer tip
Budget for legal replacement plates; check fixing and any bike-rack or tow-bar obstruction.
Severity
Often a recurring model pattern
Steering system excessively rough
- Recorded
- 20 MOT defect notes
- DVSA code
- 2.1.1 (a)
What it means
The steering feels rough through its travel, which can indicate wear in joints, column or assistance components.
Why it happens
Dry joints, worn UJs or struggling power assistance create notchy or rough steering feel.
Buyer tip
Turn lock-to-lock with the engine running and listen for grating or uneven resistance.
Severity
Often a recurring model pattern
Power steering malfunctioning
- Recorded
- 10 MOT defect notes
- DVSA code
- 2.1.5 (a)
What it means
Power steering assistance is malfunctioning, making the car heavier and less predictable to steer.
Why it happens
Low fluid, pump faults, leaks or electric PAS failures remove assistance.
Buyer tip
Check fluid (if hydraulic), look for leaks, and verify electric PAS warnings on the dash.
Severity
Often a recurring model pattern
Anti-lock braking system wiring excessively damaged
- Recorded
- 8 MOT defect notes
- DVSA code
- 1.6 (d)
What it means
The ABS system is reporting a fault or its wiring is damaged. You may lose anti-lock control in an emergency stop.
Why it happens
Wheel-speed sensors, damaged wiring or module faults set ABS warnings.
Buyer tip
Scan for ABS codes, check wheel-speed sensor wiring, and do not ignore a lit ABS lamp.
Severity
Often a recurring model pattern
Steering column universal joint has excessive wear or play
- Recorded
- 8 MOT defect notes
- DVSA code
- 2.2.2 (c)
What it means
Play or wear in a steering-column joint can feel like vagueness or a knock through the wheel.
Why it happens
Intermediate shaft joints wear with mileage and can develop free play.
Buyer tip
Have a technician check column UJs and intermediate shafts if you feel notchiness.
Severity
Often a recurring model pattern
Recent year-by-year category counts
Defect-note totals by calendar year in the serving extract (not MOT tests, not vehicles, and not a prediction).
| Year | Owner maintenance | Wear & tear | Systemic | Other |
|---|---|---|---|---|
| defect notes | defect notes | defect notes | defect notes | |
| 2021 | 40,789 | 6,892 | 1,142 | 10,343 |
| 2022 | 51,770 | 10,481 | 1,478 | 14,013 |
| 2023 | 58,360 | 14,759 | 1,937 | 17,871 |
| 2024 | 63,739 | 19,125 | 2,577 | 21,136 |
| 2025 | 63,542 | 24,031 | 2,945 | 23,744 |
| 2026 | 31,339 | 13,102 | 1,553 | 11,364 |
Buying a used Audi A4: practical MOT checks
- Inspect tyres and brake discs carefully; volume MOT wording is still dominated by consumables.
- Check for engine management warnings and oil service history appropriate to the engine.
- Compare A4 MOT outcomes with 3 Series and other peers before you pay a badge premium.
- Prefer cars with stamped or digital service records that match the mileage.
Frequently asked questions
- What is the Audi A4 MOT pass rate at 5–10 years?
- In the 2016–2021 registration band, the Audi A4 shows an 86.5% MOT pass rate across about 478,000 recorded DVSA tests in this dataset.
- How does the A4 compare with the BMW 3 Series on MOT pass rate?
- In this same age band snapshot, the BMW 320 stem posts a higher pass rate than the A4, but sample sizes and model mixes differ. Use the interactive compare tool for a like-for-like decision.
- Does this page replace an Audi dealer inspection?
- No. It is model-level MOT research to inform your shortlist. Always inspect the specific car and review its individual MOT history.