Performance by cohort

3 year bands · 188,892 tests

Pass rate climbs 10.9 points across the cohorts — newer A examples clear the test more reliably than the early cars.

Pre-2018 cohort 510

Pass

81.0%

Fail

15.5%

PRS

2.9%

Avg mileage at test

61,182 mi

2018–2020 cohort 150,755

Pass

89.8%

Fail

7.9%

PRS

1.9%

Avg mileage at test

37,455 mi

2021+ cohort 37,627

Pass

91.9%

Fail

5.8%

PRS

1.9%

Avg mileage at test

26,267 mi

Cohort = vehicle's first-registration year band. Same model, different generations of build.

Generations on file · 4

Mercedes Benz A · UK market

Photos: Wikimedia Commons · CC BY-SA / CC BY / public domain.

The picture

Mercedes Benz A: solid MOT record across 81,844 tests

The Mercedes Benz A is a petrol-powered car sold in the UK market across multiple generations, covering a broad date range in the test population.

MOT data from 81,844 tests puts this car on an 88.5% first-time pass rate, well above the UK fleet average. Average mileage at test is 29,455 miles. The most common fail item is tyre tread below the legal limit, followed by damaged tyre sidewall or structure.

For used buyers, the A's pass rate suggests it clears the MOT with fewer surprises than most — but the top failure items above are still worth a pre-purchase inspection, particularly on higher-mileage examples.

ABI Insurance Group

Group 20–36

Above average — worth comparing quotes before buying. Lower groups cost less to insure; UK fleet average is around Group 22.

Source: ABI Group Rating Panel · administered by Thatcham Research · groups cover standard variants; performance trims may sit higher. Browse all insurance groups →

20–36

out of 50

Compare quotes →

Top ten reasons for rejection.

Filter failures:

Hide wear items to see the model's real defects.

01

Tyre tread depth not in accordance with the requirements

2,681 occurrences · 1.4% of tests
02

Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view

2,653 occurrences · 1.4% of tests
03

A tyre seriously damaged

2,373 occurrences · 1.3% of tests
04

a brake lining or pad worn below 1.5mm

1,995 occurrences · 1.1% of tests
05

Wiper blade defective

1,935 occurrences · 1.0% of tests
06

A tyre cords visible or damaged

1,303 occurrences · 0.7% of tests
07

An SRS malfunction indicator lamp (MIL) indicates a system malfunction

965 occurrences · 0.5% of tests
08

Wiper blade missing or obviously not clearing the windscreen

682 occurrences · 0.4% of tests
09

A tyre seriously damaged

488 occurrences · 0.3% of tests
10

Windscreen washers not working or not providing sufficient fluid to clear the windscreen

444 occurrences · 0.2% of tests

Counts cover Major and Dangerous defects logged at test. Advisory items excluded so this shows why a car was rejected, not just what the tester flagged in passing.

Worst-case fix budget · top 3 failures

£160–£300

If every one of this A's most-logged Major fails hit at the same MOT, that's the real-world UK garage range. Reality is usually one or two items, not all of them. Open the estimator →

Try the calculator

Build your own retest budget.

Year-band analysis

Best year to buy. Worst to avoid.

First-time MOT pass rate split by registration band. A 10.9-point gap between bands means the year you buy Mercedes Benz A has a real effect on what turns up at the garage.

Best band to buy

91.9%

2021+ registration

the 2021-on band climbs to 91.9% — a 10.9-point improvement. Tests in this band average 26,267 miles — roughly 35K miles fewer on the clock than the older band. Failures here are mostly wear items: blade defective, has a cut in excess of the… — the structural issues that drag down older examples don't appear in the top-10 for this band. Post-2020 examples are early in their MOT life and generally show the cleanest records.

Band to be cautious about

81.0%

Pre-2018 registration

On the older band (pre-2018), the data shows a 81.0% pass rate against a fleet average of 91.9% on the newer band. The main culprits logged at test: tread depth below requirements of 1.6mm, has ply or cords exposed, and less than 1.5 mm thick. Average mileage on test for this band is 61,182 miles — high-mileage wear items are a recurring theme.

Best band to buy: 2021+ (91.9% first-time pass). Worst band to avoid: pre-2018 (81.0% pass). That's a 10.9-point spread across 510 older tests and 37,627 newer ones — year of build makes a material difference on this model.

Year-spread leaderboard →

Tools that pre-empt a retest.

Picked against this car's top failure patterns. Affiliate links to Amazon UK — we earn a small cut at no cost to you. Disclosed up-front, doesn't shape the data.

Item 01 · Amazon UK

Digital tyre-tread depth gauge

Five quid for a gauge beats £150 for a retest. UK MOT minimum is 1.6mm — most testers fail anything below 2mm to be safe.

Search Amazon UK

Item 02 · Amazon UK

Brake pad measurement gauge

Testers fail pads under 1.5mm. A wear gauge tells you if you've got two months left or two weeks.

Search Amazon UK

Item 03 · Amazon UK

Bosch Aerotwin wiper blades

Cheap wipers fail the test on smear streaks. Bosch Aerotwins last a winter and clear a screen properly.

Search Amazon UK

My Motor World · affiliate

Parts & supplies for this fix

Affiliate links — small commission, no extra cost to you.

Denso

Denso W14E Spark Plug (Single)

£1.09

View at My Motor World →

Denso

Denso W16EX-U Spark Plug (Single)

£1.09

View at My Motor World →

Denso

Denso W16FSR Spark Plug (Single)

£1.09

View at My Motor World →

Denso

Denso W9LM-US Spark Plug (Single)

£1.09

View at My Motor World →

Click Mechanic · affiliate

Book a mobile mechanic

Affiliate links — small commission, no extra cost to you.

Mobile mechanic · UK-wide

Book a mechanic at your door.

Fixed-price quotes upfront. No garage needed. Click Mechanic sends a vetted local mechanic to you — home, work, or roadside.

Get a quote →

Buying or keeping an A?

Use the failure ranking as a pre-test checklist or a haggling lever. Treat the headline pass rate as a fleet-wide trend, not a guarantee on any individual car.

If you own an A and your last MOT looked nothing like the ranked failures above, that's normal — individual cars vary widely. The ranking shows the patterns testers flag most often across the country.