Should I check the MOT history before buying a 2021 Audi A4 S Line 35 TDI MHEV S A?

Yes. Look for recurring advisories — slow-building issues like corrosion or brake wear patterns show up years before they become failures. A full MOT history analysis will highlight patterns that a single test result won't reveal.

What corrosion should I look for when inspecting a 2021 Audi A4 S Line 35 TDI MHEV S A?

Check brake pipes, sills, subframes, and chassis legs. Surface rust is normal at this age; structural rust is a serious problem that is expensive to fix and can fail an MOT.

How are tyres and brakes typically on a 2021 Audi A4 S Line 35 TDI MHEV S A?

Tyres and brakes are the most common advisory items on vehicles of this age. Budget for replacement if they are near the limit, and factor this into your offer price.

Is the 2021 Audi A4 S Line 35 TDI MHEV S A reliable?

Based on MOT data from 1,291 vehicles, the 2021 Audi A4 S Line 35 TDI MHEV S A has a first-time MOT pass rate of 91.9%, indicating generally reliable for its class. Always check the full MOT history of any specific vehicle before buying.

Do I need an HPI check when buying a 2021 Audi A4 S Line 35 TDI MHEV S A?

Yes. The MOT history will not show outstanding finance, insurance write-offs, or stolen status. An HPI check covers these areas and should be part of any used car purchase.

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Audi A4 S Line 35 TDI MHEV S A (2021)

1,291 real MOT outcomes analysed • 91.9% first-time pass rate

2021 Audi A4 S Line 35 TDI MHEV S A

CarHunch analysed 1,291 real MOT records for the 2021 Audi A4 S Line 35 TDI MHEV S A. Real test outcomes — pass rates, defect profiles, mileage data — from verified DVLA records. Updated as new MOTs are recorded.
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AI Analysis Reliability Overview Check a Specific Reg Buyer's Checklist Pass Rate by Fuel Mileage Distribution MOT Averages Colour Breakdown Compare Models

This 2021 A4 S Line diesel hybrid is more reliable than average, with an 86.2% first-time pass rate that's 6.2 percentage points above the UK baseline—and only 10.9% of vehicles have ever recorded a dangerous defect, which is reassuringly low. The diesel engine itself shows no particular weakness compared to petrol alternatives, since the fuel breakdown is almost entirely diesel.

At 41,657 miles median for a three-year-old car, these are genuinely low-mileage examples, which explains why failures average just 0.24 per vehicle—most issues caught are minor advisories (1.7 per car, typically wear items). Before buying, get an independent inspection focused on the hybrid battery and dual-clutch transmission, as these complex systems won't show their true condition until higher mileage.

The 2021 Audi A4 S Line 35 TDI MHEV S A passes its MOT first time more often than most UK vehicles (91.9% vs ~80% average) — and when it does fail, it's usually something minor and cheap to fix.

⚠️ About 1 in 12 of these vehicles have had a dangerous MOT failure at some point — usually tyres or brakes, and often a one-off issue rather than a persistent problem. The group stats won't tell you which one you're looking at.

First-time pass

91.9%

UK average ~80%

Better than average

Dangerous (ever)

10.9%

At least once in MOT history

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Avg failures / car

0.24

Over 2.2 tests on record

Low

Typical mileage

42k

Middle half: 33k–52k

For context

✅ Good baseline reliability. A 91.9% first-time pass rate puts this well above the UK average — it's a well-sorted vehicle in this age bracket.

🔧 Expect consumable spend. An average of 1.7 advisories per vehicle tells you wear items (tyres, brakes) get flagged regularly. Budget for them — they're not surprises.

🔍 The dangerous defect figure is real. Most are one-off tyre failures or brake issues — not structural problems. But it's exactly why checking the individual vehicle's history is essential, not optional.

These stats describe 1,291 vehicles as a group. The specific vehicle you're looking at could be the one good example or the one outlier. Run its registration to find out.

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See this vehicle's full MOT history & AI hunches

Spot recurring advisories, hidden issues, and how it compares to 1,291 Audi A4 S Line 35 TDI MHEV S A cars.

Before you buy a 2021 Audi A4 S Line 35 TDI MHEV S A

Based on MOT data from 1,291 vehicles — here's what to check.

📋 Check the full MOT history. 10.9% of these vehicles have had a dangerous defect recorded - recurring advisories often signal problems years before they become failures.
Search the reg on CarHunch for the full MOT history, reliability stats and a free AI-powered analysis of that exact vehicle.
🔍 Brake pipes, sills and subframes are the key areas on a vehicle this age — structural rust is hard to spot without getting underneath. A mechanic will check all of this before you commit, and give you a concrete basis to negotiate on price. Inspection →
📄 Outstanding finance, insurance write-offs and clocking won't appear in the MOT records — a dedicated history check covers all of this. Our link gets you 20% off automatically. History Get 20% off via CarHunch

Pass Rate by Fuel Type

Fuel type	Vehicles	Pass rate	Avg failures
Diesel (100%)	1,286	91.9%	0.24

Colour Breakdown

Based on 2,171 Audi A4 S Line 35 TDI MHEV S A vehicles registered in the UK — across all years. From DVLA registration records.

Grey 34.9%

758

Black 27.6%

599

Blue 20.5%

444

White 15.6%

338

Red 0.8%

Green 0.7%

Mileage Distribution

Most 2021 Audi A4 S Line 35 TDI MHEV S A vehicles sit in the blue band. If the vehicle you're looking at is outside it, it's either unusually low or high mileage for its age.

41,657

typical

32,969

low mileage

51,911

high mileage

Half of all 2021 Audi A4 S Line 35 TDI MHEV S A vehicles fall between 32,969 and 51,911 miles.

Is the mileage you're seeing normal?

✓ Under 32,969 miles — lower than most. Could be great, or could be a vehicle that rarely moved. Check test frequency and mileage progression in the MOT history.

✓ 32,969–51,911 miles — normal for age. This is where most 2021 Audi A4 S Line 35 TDI MHEV S As sit.

⚠ Over 70,079 miles — higher than typical. Not necessarily a problem, but check service history and look out for advisory build-up on tyres and brakes.

MOT History Averages

2.2

Avg MOT tests per vehicle

0.24

Avg failures per vehicle

1.7

Avg advisories per vehicle

Other model years — Audi A4 S Line 35 TDI MHEV S A: All A4 S Line 35 TDI MHEV S A years → Which year to buy? →

2022 2023 2024

Or browse all models: Audi →

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See how the 2021 Audi A4 S Line 35 TDI MHEV S A stacks up against a rival.

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