Model Reports 4 min read Updated 18 Oct 2026

Mercedes-Benz CLS 2012: reliability & common MOT faults

In 2025, 74 in every 100 first MOTs on a 2012 Mercedes-Benz CLS were passes.

Summary

The 2012 Mercedes-Benz CLS follows the pattern of the model years either side.

At a glance

How 1,012 first tests went in 2025.

Passed first time
74 in every 100
Did not pass first time
26 in every 100268 failed first-attempt tests
The typical car
13 yearsabout 101,022 miles
First tests counted
1,012

How we count this. Data: UK MOT open data, 2025. Only Class 4 cars on their first MOT of the year are counted. A car that fails and is fixed at the test station still counts as a fail in the first-attempt rate. These are raw results, not adjusted for age, mileage, or peer mix. The MOT does not test engine or gearbox internals.

Note:

These are patterns across 2012 Mercedes-Benz CLS vehicles in 2025, not a prediction that any one car will have them. Faults are grouped by part of the car. A wear pattern follows age and use more than the way the car was built. They come from MOT defect codes, not manufacturer bulletins, recalls or a diagnosis of any one car.

Suspension

Two faults. The strongest is the suspension sub-frame (rear): 34 times as often as on similar cars.

Figures below are measured across the 268 failed first attempts in 2025 that had a mileage recorded, which allows a like-for-like comparison.

We only list faults with at least 20 failures and a rate of about 2.0 times that of similar cars, which keeps one-off results out of the list.

Suspension sub-frame (rear)

Failed on 22 first tests34 times as often as similar carsPossible evidence

What it means

A suspension sub-frame insecurely attached to the chassis or axle is Major, and Dangerous when it is insecure and impairing directional stability. A sub-frame that is missing, likely to become detached, fractured or likely to fail is also Dangerous. Excessive damage or corrosion that seriously weakens it is Major.

Anti-roll bar linkage ball joint dust cover (front)

Failed on 23 first tests2.2 times as often as similar carsPossible evidence

What it means

A suspension joint dust cover that is severely deteriorated is Minor. It becomes Major once it is missing or no longer prevents the ingress of dirt, so what matters is whether it still keeps dirt out. DVSA words this for any suspension joint dust cover, and files it here under anti-roll bars.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.

Tyres

Two wear patterns. The strongest is the tyre tread depth (rear): 3.9 times as often as on similar cars.

Tyre tread depth (rear)

Failed on 33 first tests3.9 times as often as similar carsWear pattern

What it means

Only primary grooves count when tread depth is assessed: those holding the wear indicators, or cut as deep as those when new. Shallower secondary grooves are ignored. Tread depth below the minimum for the vehicle is Dangerous, and so is a pattern not visible over the whole tread, but that second row applies only to vehicles that need the lower minimum.

Tyre condition (front)

Failed on 47 first tests2.6 times as often as similar carsWear pattern

What it means

Exposed or damaged ply or cords are graded Dangerous. A cut in excess of the requirements and deep enough to reach the ply or cords is Major, and testers may open the cut with a blunt instrument to check its depth. A tyre contacting the vehicle through flexing or suspension movement is not a defect; fouling fails only at the time of test.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.

Advisories

Other things testers noted as worn or close to failing, more often than on similar cars.

An advisory is a note from the tester about something that has not failed yet. It is an early warning, not a fail.

Wheel bearings (front)

Noted on 28 first tests12 times as often as similar carsElevated evidence

Rigid brake pipes (front)

Noted on 48 first tests7.4 times as often as similar carsElevated evidence

Rigid brake pipes (rear)

Noted on 29 first tests2.9 times as often as similar carsElevated evidence

Data: UK MOT open data, 2025. Counts cover advisories recorded on failed first tests only, compared with cars of the same age and mileage.

MOT pass rates

How first tests ended, and how the pass rates are counted.

Passed first time
74in every 100
Passed on the first test.
Fixed at the station
2in every 100
Failed, then fixed at the test station the same day.
Failed
24in every 100
Did not pass, and were not fixed at the test station.

First-attempt pass 73.5% of 1,012 first tests (2025): only cars that passed first time count. Official-style pass 75.9%: cars fixed at the test station also count as a pass. The 2 fixed and the 24 not fixed make the 26 in every 100 that did not pass first time.

Same model, other years

Passed first time in every 100, all tested in 2025.

406080100200520122015Older carsNewer cars
4060801002012Older carsNewer cars

Newer cars are younger, so look for a jump rather than the climb.

YearPassed first timeFirst tests
200571 in every 100799
200670 in every 1001,098
200767 in every 1001,373
200869 in every 1001,128
200966 in every 100895
201065 in every 100927
201173 in every 1001,026
2012 This car74 in every 1001,012
201371 in every 1002,809
201474 in every 1001,644
201578 in every 1002,729
201679 in every 1002,000
201780 in every 1001,415
201883 in every 100900
201982 in every 1001,002

FAQs

Short answers about how to read this model-year guide.

The 2012 Mercedes-Benz CLS follows the pattern of the model years either side. In 2025, 73.5% of 1,012 first MOTs on the 2012 Mercedes-Benz CLS passed first time (PRS: items fixed at the station the same day, counted as a fail). The official-style rate including PRS is 75.9%. Among 268 failed first-attempt MOT tests (test year 2025), Suspension sub-frame (rear) appears more often than on similar cars (8.2% of those tests; 22 observed failures; about 34× more often than similar cars). There is no single reliability score here; this is a pre-purchase checklist built from DVSA open data, not a guarantee for any individual car.
Among failed first-attempt tests we highlight patterns that appear more often than on similar cars. Top example: Suspension sub-frame (rear) (8.2% of those tests; 22 observed failures; about 34× more often than similar cars). These are statistical signals, not a diagnosis of any individual car.
Suspension sub-frame (rear) shows up more often than on similar cars (8.2% of those tests; 22 observed failures; about 34× more often than similar cars). That does not prove a design fault. Age, mileage, and how the car was used still matter. Treat it as a pre-purchase checkpoint, not a manufacturer service bulletin.
Common MOT problem areas for the 2012 Mercedes-Benz CLS include Suspension sub-frame (rear), Anti-roll bar linkage ball joint dust cover (front). These are the faults that stand out compared with similar cars, not a complete list of what can go wrong on any individual car.
Advisories flag issues noted at the test and are not a fail rate. We show advisory patterns that appear more often than on similar cars among failed first-attempt tests, separate from common failure rows. Use them as early-warning checks, not as a pass/fail score.
This page highlights MOT failure patterns for the 2012 Mercedes-Benz CLS (registration year) using UK DVSA open data for the selected test year. Patterns are compared with cars of a similar age and mileage. It is a buyer checklist from MOT defect statistics, not a full service history or manufacturer service-bulletin list.
No. MOT tests do not cover engine internals, gearboxes, or many electronic modules. Patterns here come from MOT defect statistics only and should not be read as engine or gearbox reliability scores.

About this data

How this page is built and what it can (and can't) say.

These figures come from UK MOT open data for this model year. We surface common failure patterns against similar cars, not a full reliability score, and not a pass/fail verdict on any individual vehicle.

2024 2025

What we include

UK Class 4 cars only. Normal MOT tests (not retests); first test per vehicle per calendar year; results pass, PRS, or fail.

Same-day repairs

PRS means the car failed items that were fixed at the test station and then passed the same day. We count PRS as a first-attempt fail in headline rates so same-day repairs do not hide problems.

How we compare

We compare this model year with other Class 4 cars of similar age and mileage in the same test year. This model family is left out of the peer group so the car is not measured against itself.

What this does not cover

  • MOTs do not cover engine internals, gearboxes, or many electronics; this is not a full reliability score.
  • Common faults come from MOT defect stats, not manufacturer TSBs or recalls.
  • Age and mileage matching reduces, but does not remove, differences in how cars were used and maintained.
  • If the data for a car is too thin to say anything useful, we say so rather than guess.

Contains public sector information licensed under the Open Government Licence v3.0.

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