Model Reports 4 min read Updated 18 Oct 2026

Mercedes-Benz A-Class 2003: reliability & common MOT faults

In 2025, 54 in every 100 first MOTs on a 2003 Mercedes-Benz A-Class were passes.

Summary

With 924 first tests, there are too few to say whether the 2003 Mercedes-Benz A-Class differs from the model years either side. Treat the faults below as a checklist.

At a glance

How 924 first tests went in 2025.

Passed first time
54 in every 100
Did not pass first time
46 in every 100427 failed first-attempt tests
The typical car
22 yearsabout 77,684 miles
First tests counted
924

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 2003 Mercedes-Benz A-Class vehicles in 2025, not a prediction that any one car will have them. Faults are grouped by part of the car. They come from MOT defect codes, not manufacturer bulletins, recalls or a diagnosis of any one car.

Suspension

Two faults. The strongest is the shock absorbers (front): 4.9 times as often as on similar cars.

Figures below are measured across the 371 of 427 failed first attempts (86.9%) that recorded an odometer reading in 2025. Mileage is needed to compare like with like. 13.1% of failures are excluded because no mileage was recorded, so treat these shares as indicative for this model year.

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.

Shock absorbers (front)

Failed on 27 first tests4.9 times as often as similar carsPossible evidence

What it means

Slight seepage that leaves a film of fluid on a shock absorber does not fail it. Severe leakage, or damage so that it does not function, is Major. A shock absorber missing or likely to become detached is graded Dangerous, though a missing one is only rejected if shock absorbers were fitted as standard.

Also noted as an advisory

Testers also noted it as an advisory, worn but not yet failing, on 50 first tests, 4.7 times as often as on similar cars.

Coil spring (rear)

Failed on 25 first tests2.9 times as often as similar carsPossible evidence

What it means

A missing bump stop rubber is not a reason to fail a coil spring. When the vehicle is jacked and lowered, a spring that does not correctly locate as the suspension returns to its normal running position is rejected as insecurely attached. A missing spring is Major, and graded Dangerous where directional control is affected.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage. Advisories count notes recorded on failed first tests only.

Noise, emissions and leaks

One fault: petrol engine warning light, 2.0 times as often as on similar cars.

Petrol engine warning light

Failed on 44 first tests2.0 times as often as similar carsPossible evidence

What it means

The malfunction indicator lamp (MIL) on a petrol engine is a Major failure when it is illuminated indicating a malfunction. The detail line DVSA gives for the same row also names an inoperative lamp. The test covers only certain petrol vehicles, depending on their age, size and fuel type.

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. Advisories for the faults above are shown with those faults.

Rigid brake pipes (front)

Noted on 80 first tests2.9 times as often as similar carsElevated evidence

Suspension sub-frame (front)

Noted on 31 first tests2.9 times as often as similar carsElevated evidence

Flexible brake hoses (front)

Noted on 30 first tests2.5 times as often as similar carsElevated evidence

Non-component advisories (front)

Noted on 23 first tests2.5 times as often as similar carsElevated evidence

Rigid brake pipes (rear)

Noted on 89 first tests2.3 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
54in every 100
Passed on the first test.
Fixed at the station
11in every 100
Failed, then fixed at the test station the same day.
Failed
35in every 100
Did not pass, and were not fixed at the test station.

First-attempt pass 53.8% of 924 first tests (2025): only cars that passed first time count. Official-style pass 64.8%: cars fixed at the test station also count as a pass. The 11 fixed and the 35 not fixed make the 46 in every 100 that did not pass first time.

Same model, other years

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

4060801002003201020152020Newer cars
406080100200320102020Newer cars

Newer cars are younger, so look for a jump rather than the climb. A year earlier (2024), when these cars were a year younger, 55 in every 100 passed first time.

YearPassed first timeFirst tests
200158 in every 100416
200255 in every 100654
2003 This car54 in every 100924
200454 in every 100879
200559 in every 1002,304
200657 in every 1003,559
200757 in every 1005,100
200858 in every 1005,851
200959 in every 1006,260
201062 in every 1005,713
201166 in every 1005,097
201266 in every 1004,998
201368 in every 10014,910
201469 in every 10022,196
201572 in every 10025,391
201675 in every 10036,342
201778 in every 10039,003
201882 in every 10039,403
201985 in every 10048,623
202087 in every 10033,980
202190 in every 10028,061
202291 in every 10016,574

FAQs

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

With 924 first tests, there are too few to say whether the 2003 Mercedes-Benz A-Class differs from the model years either side. Treat the faults below as a checklist. In 2025, 53.8% of 924 first MOTs on the 2003 Mercedes-Benz A-Class passed first time (PRS: items fixed at the station the same day, counted as a fail). The official-style rate including PRS is 64.8%. Among 427 failed first-attempt MOT tests (test year 2025), Shock absorbers (front) appears more often than on similar cars (7.3% of those tests; 27 observed failures; about 4.9× 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: Shock absorbers (front) (7.3% of those tests; 27 observed failures; about 4.9× more often than similar cars). These are statistical signals, not a diagnosis of any individual car.
Shock absorbers (front) shows up more often than on similar cars (7.3% of those tests; 27 observed failures; about 4.9× 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 2003 Mercedes-Benz A-Class include Shock absorbers (front), Coil spring (rear), Petrol engine warning light. 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 2003 Mercedes-Benz A-Class (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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