2015 Mercedes-Benz A-Class diesel: common problems and MOT failures

What goes wrong more than usual on a 2015 Mercedes-Benz A-Class diesel?

Parts flagged at MOT more often on the 2015 Mercedes-Benz A-Class diesel than on all cars registered in 2015.

• Link ball joint covers7.4× usual
  Mercedes-Benz A-Class

  5.2% All 2015 cars

  0.7%

  Failed outright at MOT: 2.4%, against 0.4% of all 2015 cars. The rest were advisories or minor defects.

  Rough price £60–£150 (one joint) ClickMechanic

  At the viewing: Listen for knocking over bumps and check the rubber boots behind the wheels aren't split.

• Airbag warning light10.3× usual
  Mercedes-Benz A-Class

  3.1% All 2015 cars

  0.3%

  Failed outright at MOT: 3%, against 0.3% of all 2015 cars. The rest were advisories or minor defects.

  Rough price £10–£80 our estimate

  At the viewing: Ask a friend to check every light while you work the switches: indicators, brake lights, fog lights and reversing lights.

• Engine warning light2× usual
  Mercedes-Benz A-Class

  3% All 2015 cars

  1.5%

  Failed outright at MOT: 3%, against 1.5% of all 2015 cars. The rest were advisories or minor defects.

  Rough price £10–£80 our estimate

  At the viewing: Ask a friend to check every light while you work the switches: indicators, brake lights, fog lights and reversing lights.

• Ball joint dust cover1.7× usual
  Mercedes-Benz A-Class

  2.4% All 2015 cars

  1.4%

  Failed outright at MOT: 1%, against 0.5% of all 2015 cars. The rest were advisories or minor defects.

  Rough price £60–£150 (one joint) ClickMechanic

  At the viewing: Listen for knocking over bumps and check the rubber boots behind the wheels aren't split.

Common 2015 Mercedes-Benz A-Class diesel MOT failures and advisories

The share of 2015 Mercedes-Benz A-Class diesel MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

• Tyres
  35% of testsRough price £70–£150

  At the viewing: Check the tread on all four tyres, including the inside edges, and look for cracks or bulges.

• Brakes
  24% of testsRough price £150–£350

  At the viewing: Look for a lip on the disc edges and feel for judder or pulling when braking firmly from about 40mph.

• Suspension
  15% of testsRough price £120–£400

  At the viewing: Listen for knocks over speed bumps, and look behind each front wheel for a snapped coil spring.

• Lights and electrics
  13% of testsRough price £10–£80

  At the viewing: Ask a friend to check every light, including brake lights and indicators, while you operate them.

• Wipers, windscreen and mirrors
  7% of testsRough price £15–£250

  At the viewing: Check for chips in the driver's view, and test the wipers and washers.

• Seats and seatbelts
  2% of testsRough price £80–£250

  At the viewing: Pull each seatbelt sharply. It should lock, and retract cleanly.

Known faults on the 2015 Mercedes-Benz A-Class diesel

Reported by owners, mechanics and buying guides for this model and age. Check which engine the car has, as some apply to one engine only.

• Oil leak and engine recalls

  All engines

  Recalls covered engine oil leaks and a fault that could cause engine failure.

  At the viewing: Look for oil under the car and around the engine, and ask a Mercedes dealer to check the VIN.

  Source: Carbuyer: used Mercedes A-Class Mk3 reliability

• Driveshaft recall

  All engines

  A 2015 recall covered the driveshafts.

  At the viewing: Listen for clicking on full lock and feel for vibration when accelerating.

  Source: Carbuyer: used Mercedes A-Class Mk3 reliability

• Electrical faults and rattles

  All engines

  Electrical issues were the top owner complaint, and early cars had seatbelt and dashboard rattles.

  At the viewing: Test every electric function and listen for rattles over bumps.

  Source: Carbuyer: used Mercedes A-Class Mk3 reliability

Questions to ask the seller before buying a 2015 Mercedes-Benz A-Class diesel

Ask before you travel to see it. A seller who knows the car will have answers, and receipts.

1. Has all the recall work been done?
2. Has the driveshaft recall been done?
3. Have there been any electrical faults?
4. Any recent work on the link ball joint covers? (Flagged at MOT 7.4× as often on the 2015 Mercedes-Benz A-Class diesel as on other cars the same age.)
5. Any recent work on the airbag warning light? (Flagged at MOT 10.3× as often on the 2015 Mercedes-Benz A-Class diesel as on other cars the same age.)
6. Any recent work on the engine warning light? (Flagged at MOT 2× as often on the 2015 Mercedes-Benz A-Class diesel as on other cars the same age.)