Mercedes-Benz A-Class common problems

By component

What wears out on a A-Class

Failure items grouped by the part behind them, with the share of failed Mercedes-Benz A-Class tests recording each. A part can carry several DVSA wordings; they are listed beneath. One failed test often lists several items, so shares do not sum to 100%.

1. 1.Tyres

   45.0% of failed tests

   Tread wears with every mile and sidewalls age and take kerb damage; the legal minimum is 1.6 mm across the central three-quarters.

   • “Tyre tread depth not in accordance with the requirements” — explained15.5%
   • “A tyre seriously damaged” — explained11.1%
   • “A tyre cords visible or damaged” — explained9.0%
   • “A tyre seriously damaged” — explained4.2%

   Across all cars, tyres failures run at a similar rate at every age, because they are replaced on a cycle rather than wearing out with the car. How long tyres last

2. 2.Suspension bushes

   19.5% of failed tests

   Rubber bushes in arms and links perish and split with age and load; the most recorded suspension item on the test.

   • “A suspension joint dust cover missing or no longer prevents the ingress of dirt etc” — explained9.4%
   • “A suspension pin, bush or joint excessively worn” — explained4.6%
   • “A suspension joint dust cover missing or no longer prevents the ingress of dirt etc” — explained3.9%
   • “A suspension pin, bush or joint excessively worn” — explained1.5%

   Across all cars, suspension bushes failures climb 20-fold between three and fifteen years, peaking at 15+ years. How long suspension bushes last

3. 3.Coil springs

   15.8% of failed tests

   Springs fatigue and corrode where the coating chips, then snap, often at the bottom coil; potholes and salt accelerate it.

   • “A spring or spring component fractured or seriously weakened” — explained15.8%

   Across all cars, coil springs failures climb 20-fold between three and fifteen years, peaking at 12–14 years. How long coil springs last

4. 4.Wiper blades and washers

   15.3% of failed tests

   Rubber blades harden and split within a year or two; washer jets block and pumps fail.

   • “Windscreen washers not working or not providing sufficient fluid to clear the windscreen” — explained6.3%
   • “Wiper blade missing or obviously not clearing the windscreen” — explained6.1%
   • “Windscreen washers not working or not providing sufficient fluid to clear the windscreen” — explained3.0%

   Across all cars, wiper blades and washers failures run at a similar rate at every age, because they are replaced on a cycle rather than wearing out with the car. How long wiper blades and washers last

5. 5.Brake pads and shoes

   13.3% of failed tests

   Friction material wears with use; the MOT limit is 1.5 mm and a pad that thin is close to metal on metal.

   • “a brake lining or pad worn below 1.5mm” — explained11.3%
   • “Brake lining or pad worn down to wear indicator” — explained1.9%

   Across all cars, brake pads and shoes failures run at a similar rate at every age, because they are replaced on a cycle rather than wearing out with the car. How long brake pads and shoes last

6. 6.Bulbs and lamps

   11.5% of failed tests

   Filament bulbs simply expire; the cheapest and most avoidable failure on the test, and one of the most recorded.

   • “A direction indicator lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning” — explained3.5%
   • “Stop lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning” — explained2.9%
   • “A headlamp or light source missing, inoperative or more than ½ not functioning in the case of LED” — explained2.7%
   • “A lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning” — explained2.4%

   Across all cars, bulbs and lamps failures climb 15-fold between three and fifteen years, peaking at 15+ years. How long bulbs and lamps last

7. 7.Engine management

   8.7% of failed tests

   The MIL lamp lit is a failure in itself, whatever the stored code; the fault codes section explains what lies behind it.

   • “Engine MIL illuminated indicating a malfunction” — explained4.4%
   • “Engine MIL illuminated indicating a malfunction” — explained4.3%

8. 8.Headlamp aim

   7.7% of failed tests

   Aim drifts with sagging suspension, a knocked lamp or a botched bulb change; adjustment, not a part.

   • “The aim of a headlamp is not within limits laid down in the requirements” — explained4.1%
   • “The aim of a headlamp is not within limits laid down in the requirements” — explained2.1%
   • “The aim of a headlamp is not within limits laid down in the requirements” — explained1.5%

By registration year

A-Class problems by year

MOT pass rate for Mercedes-Benz A-Class cars by the year they were first registered, from years with at least 1,000 tests. Every car in a row is the same age, so the rate is raw. Neighbouring years differ by a year of wear — a step of a point or two is age. The step at 2018, up 4.6 points, is larger than wear explains and most likely marks a change in the cars themselves.

Last column: change on the previous year, in points. Years registered within the last three years have not yet been tested and are not shown.

Before it fails

What testers warn A-Class owners about

Advisories are the same parts a year or two earlier. Share of all Mercedes-Benz A-Class tests carrying an advisory for each.

• Tyres43.9% of tests
• Brake discs16.2% of tests
• Brake pads and shoes10.2% of tests
• Brake pipes5.2% of tests
• Suspension bushes3.6% of tests

Go deeper

The rest of the A-Class file

• Mercedes-Benz A-Class: pass rate, ranking and the full failure record
• Is a A-Class's mileage high for its age?
• Every Mercedes-Benz model compared
• Check a specific car's MOT history

Common questions

What are the most common problems with a Mercedes-Benz A-Class?

Going by what fails the MOT, tyres (recorded in 45.0% of failed tests), suspension bushes (recorded in 19.5% of failed tests), and coil springs (recorded in 15.8% of failed tests). These are the items testers actually record across 365,510 tests, not reports from owners, so they describe what goes wrong at the point where it has to be fixed.

Which Mercedes-Benz A-Class year is the most reliable?

By MOT pass rate, Mercedes-Benz A-Class cars registered in 2022 do best at 90.3% and 2006 cars do worst at 57.4%. Most of that ordering is simply age — newer cars pass more — so read the year table for steps larger than a couple of points between neighbouring years; those mark a change in the cars rather than the calendar. The largest such step is at 2018, up 4.6 points on 2017.

Is the Mercedes-Benz A-Class reliable?

Adjusted for the age and mileage of the cars tested, the Mercedes-Benz A-Class passes 73.3% of MOTs against a national 72.3%. An MOT measures roadworthiness on the day rather than breakdowns or running costs, so this is a reliability measure in the narrow sense: how often the car meets the legal standard, and what stops it.

What should I check when buying a used Mercedes-Benz A-Class?

Start with what fails most: tyres, suspension bushes, coil springs. Then read the car's own MOT history for advisories carried year to year without repair — the model tells you what to expect, the history tells you whether this owner dealt with it.