Mercedes Benz
129,996 MOT tests analysed. sits above the UK fleet average — here's where Glas pass, fail, and end up on the retest sheet.
That's 9.0 points above the UK fleet average across our 1,984 tracked models — a confident result.
Pass
86.5%
Pass-after-fix
2.3%
Fail
10.8%
Avg miles
54,625
Pass + Pass-after-fix + Fail = 100%
Trim variants
Performance by cohort
2 year bands · 129,993 tests
Pass rate climbs 2.9 points across the cohorts — newer Gla examples clear the test more reliably than the early cars.
Pass
85.5%
Fail
11.6%
PRS
2.4%
Avg mileage at test
62,215 mi
Pass
88.4%
Fail
9.1%
PRS
2.1%
Avg mileage at test
39,807 mi
Cohort = vehicle's first-registration year band. Same model, different generations of build.
Generations on file · 2
Mercedes Benz Gla · UK market
2013–2019
2019–now
Photos: Wikimedia Commons · CC BY-SA / CC BY / public domain.
The picture
The Mercedes Benz GLA is a diesel-powered car sold in the UK market across multiple generations, covering a broad date range in the test population.
MOT data from 73,136 tests puts this car on an 86.4% first-time pass rate, well above the UK fleet average. Average mileage at test is 46,834 miles. The most common fail item is tyre tread below the legal limit, followed by brake pads worn below 1.5mm.
For used buyers, the GLA'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
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 →
22–36
out of 50
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Tyre tread depth not in accordance with the requirements
2,210 occurrences · 1.7% of tests
A suspension joint dust cover severely deteriorated
1,896 occurrences · 1.5% of tests
a brake lining or pad worn below 1.5mm
1,435 occurrences · 1.1% of tests
A spring or spring component fractured or seriously weakened
1,378 occurrences · 1.1% of tests
A transmission shaft constant velocity joint boot missing or no longer prevents the ingress of dirt etc
1,322 occurrences · 1.0% of tests
A suspension joint dust cover missing or no longer prevents the ingress of dirt etc
1,300 occurrences · 1.0% of tests
A transmission shaft constant velocity joint boot severely deteriorated
1,266 occurrences · 1.0% of tests
Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view
1,244 occurrences · 1.0% of tests
Wiper blade defective
1,242 occurrences · 1.0% of tests
A tyre seriously damaged
1,093 occurrences · 0.8% 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 4 failures
£300–£735
If every one of this Gla'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
First-time MOT pass rate split by registration band. A 2.9-point gap between bands is modest — the year you buy Mercedes Benz Gla makes a small but real difference to MOT outcomes.
Best band to buy
88.4%
2018–2020 registration
the 2018–2020 band climbs to 88.4% — a 2.9-point improvement. Tests in this band average 39,807 miles — roughly 22K miles fewer on the clock than the older band. Failures here are mostly wear items: tread depth below requirements of 1.6mm, less than 1.5 mm thick — the structural issues that drag down older examples don't appear in the top-10 for this band. The stricter post-2018 MOT test rules meant manufacturers had to tighten up emissions and electrical checks, but this band still shows far fewer major failures on suspension and bodywork than the older fleet.
Band to be cautious about
85.5%
Pre-2018 registration
On the older band (pre-2018), the data shows a 85.5% pass rate against a fleet average of 88.4% 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 62,215 miles — high-mileage wear items are a recurring theme.
Best band to buy: 2018-2020 (88.4% first-time pass). Worst band to avoid: pre-2018 (85.5% pass). That's a 2.9-point spread across 85,980 older tests and 44,013 newer ones — year of build makes a material difference on this model.
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
My Motor World · affiliate
Affiliate links — small commission, no extra cost to you.
Click Mechanic · affiliate
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.
Recall history
The Gla has 31 official UK vehicle recalls covering defect details, remedies, and affected build dates.
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 Gla 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.
