2019 Mercedes-Benz A-Class diesel: common problems and MOT failures

What goes wrong more than usual on a 2019 Mercedes-Benz A-Class diesel?

Parts flagged at MOT more often on the 2019 Mercedes-Benz A-Class diesel than on all cars registered in 2019.

• Airbag warning light14× usual
  Mercedes-Benz A-Class

  2.8% All 2019 cars

  0.2%

  Failed outright at MOT: 2.8%, against 0.2% of all 2019 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 joint3.3× usual
  Mercedes-Benz A-Class

  2.3% All 2019 cars

  0.7%

  Failed outright at MOT: 0.4%, against 0.2% of all 2019 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.

• Engine warning light2.5× usual
  Mercedes-Benz A-Class

  2% All 2019 cars

  0.8%

  Failed outright at MOT: 2%, against 0.8% of all 2019 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.

Common 2019 Mercedes-Benz A-Class diesel MOT failures and advisories

The share of 2019 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
  31% 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
  17% 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.

• Lights and electrics
  6% 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
  5% of testsRough price £15–£250

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

• Suspension
  4% 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.

• 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 2019 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.

• Many recalls (22 so far)

  All engines

  This A-Class has had 22 recalls, including faulty crankshafts that needed a new engine, leaking turbos, suspension uprights, loose rear axle bolts, the emergency braking system and the panoramic roof.

  At the viewing: Ask a Mercedes dealer to check the VIN, and get proof every recall has been done.

  Source: Auto Express: used Mercedes A-Class (Mk4, 2018 on) review

Questions to ask the seller before buying a 2019 Mercedes-Benz A-Class diesel

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

1. Have all the recalls been done? Can a Mercedes dealer confirm from the VIN?
2. Any recent work on the airbag warning light? (Flagged at MOT 14× as often on the 2019 Mercedes-Benz A-Class diesel as on other cars the same age.)
3. Any recent work on the ball joint? (Flagged at MOT 3.3× as often on the 2019 Mercedes-Benz A-Class diesel as on other cars the same age.)
4. Any recent work on the engine warning light? (Flagged at MOT 2.5× as often on the 2019 Mercedes-Benz A-Class diesel as on other cars the same age.)
5. Can I see the service history and receipts for any big jobs?