Performance by cohort

3 year bands · 130,667 tests

Pass rate climbs 6.3 points across the cohorts — newer Cla examples clear the test more reliably than the early cars.

Pre-2018 cohort 77,865

Pass

83.4%

Fail

13.1%

PRS

3.0%

Avg mileage at test

74,928 mi

2018–2020 cohort 39,145

Pass

87.6%

Fail

9.7%

PRS

2.3%

Avg mileage at test

42,138 mi

2021+ cohort 13,657

Pass

89.7%

Fail

7.4%

PRS

2.5%

Avg mileage at test

28,793 mi

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

Generations on file · 3

Mercedes Benz Cla · UK market

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

The picture

CLA at 82.7%: above average compact executive, with brake pads and lamps to watch

The Mercedes-Benz CLA posts 82.7% first-time pass from 59,562 tests at an average presenting mileage of 55,018. Top failures are tyre tread, brake pads below 1.5mm and rear plate lamp faults. The CLA's sport-tuned suspension and large front brake calipers accelerate front pad consumption — buyers who run the car on motorways may underestimate city brake usage that wears pads faster. LED rear lamp failures appear in the top ten, consistent with Mercedes' complex rear lighting designs. Shock absorber deterioration also features. At 82.7% and above average, the CLA is a solid prospect; check brake pads and rear lamp function.

ABI Insurance Group

Group 26–40

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 →

26–40

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

2,257 occurrences · 1.7% of tests
02

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

2,099 occurrences · 1.6% of tests
03

A tyre cords visible or damaged

2,027 occurrences · 1.6% of tests
04

A tyre seriously damaged

1,825 occurrences · 1.4% of tests
05

A suspension joint dust cover severely deteriorated

1,562 occurrences · 1.2% of tests
06

a brake lining or pad worn below 1.5mm

1,451 occurrences · 1.1% of tests
07

A spring or spring component fractured or seriously weakened

1,436 occurrences · 1.1% of tests
08

Wiper blade defective

1,054 occurrences · 0.8% of tests
09

A suspension joint dust cover missing or no longer prevents the ingress of dirt etc

840 occurrences · 0.6% of tests
10

A tyre seriously damaged

813 occurrences · 0.6% 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

£200–£430

If every one of this Cla'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 6.3-point gap between bands means the year you buy Mercedes Benz Cla has a real effect on what turns up at the garage.

Best band to buy

89.7%

2021+ registration

the 2021-on band climbs to 89.7% — a 6.3-point improvement. Tests in this band average 28,793 miles — roughly 46K miles fewer on the clock than the older band. Failures here are mostly wear items: has a cut in excess of the…, blade defective — 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

83.4%

Pre-2018 registration

On the older band (pre-2018), the data shows a 83.4% pass rate against a fleet average of 89.7% on the newer band. The main culprits logged at test: ball joint dust cover severely deteriorated, tread depth below requirements of 1.6mm, and fractured or broken. Average mileage on test for this band is 74,928 miles — high-mileage wear items are a recurring theme.

Best band to buy: 2021+ (89.7% first-time pass). Worst band to avoid: pre-2018 (83.4% pass). That's a 6.3-point spread across 77,865 older tests and 13,657 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

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 →

Recall history

34 UK recalls on record.

The Cla has 34 official UK vehicle recalls covering defect details, remedies, and affected build dates.

See all recalls

Buying or keeping a Cla?

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 a Cla 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.