Mercedes-Benz A-Class Common Faults in the UK
W177 (2018–present) — Premium compact hatchback competing with the Audi A3 and BMW 1 Series in the UK's small executive/family hatchback segment. Updated 6 October 2026.
This guide covers the W177 (2018–present) only. Older A-Class generations have different engines and faults — for one of those, see how to check any car for known faults.
The Mercedes-Benz A-Class W177 (2018–present) is a premium hatchback rivalling the Audi A3 and BMW 1 Series. The key check is the 7G-DCT dual-clutch gearbox: drive it from cold, feel for jerky take-up, and look for transmission fluid changes in the history. Launch-year 2018–2019 cars carry the most MBUX and DCT complaints. Best buy: 2023–2025 facelift.
Largest DVSA recall for the A-Class: R/2024/166, 182,919 vehicles — Backup function of steering software. See the 11 DVSA recalls listed for this model.
88.4% of Mercedes-Benz A-Class cars registered 2018–2022 pass the MOT first time, level with all cars registered in those years (87.6%). These are the cars this guide covers that were 3 to 12 years old when DVSA tested them in 2025, counted from 17,996 DVSA tests; a pass with rectification at the station counts as a pass here, and as a failure in DVSA's own initial-test measure.
Counting every registration year DVSA holds for the Mercedes-Benz A-Class (2005–2022), which includes generations this guide does not cover, 81.8% pass first time, from 38,379 tests.
Source: DVSA MOT Anonymised Data 2025 (Open Government Licence v3.0). Class 4 tests in Great Britain, test type NT (a normal annual test), retests excluded. A pass, or a pass with rectification at the station, counts as a first-time pass; DVSA's own initial-test measure counts a rectified pass as a failure and so reports a lower figure. Testing in Northern Ireland is run separately by the DVA under its own rules. Compared against cars of the same registration years, because pass rates otherwise mostly measure how old a model's surviving fleet is.
See it by registration year and by mileage ↓The asking-price figures above are the middle 80% and the median of what sellers were asking on Autoza on 16 October 2026 — not what buyers pay — for Mercedes-Benz A-Class cars registered from 2018. They are worked out from the cars on sale when this page is generated, and none is shown when fewer than 10 cars qualify. The road tax line comes from GOV.UK's vehicle tax rate tables (2026/27 rates). The other quick-stats values are indicative editorial estimates aggregated from owner-forum sentiment, recall data and reliability surveys. We do not publish a UK price index, and no figure here should be quoted as one.
Best and worst years to buy
We name a year as a best or worst buy only where the DVSA MOT table further down does not rate it the other way.
The 2023–2025 facelifted W177 benefits from several years of dealer software updates to MBUX, revised DCT clutch/software mapping, and production running changes that addressed the electrical and gearbox complaints most commonly reported on early cars, making these the safer years to buy on reliability grounds.
2023, 2024 and 2025 cars are too new for the DVSA table below, so there is no MOT record behind them yet.
2018 and 2019 were the UK launch years for the W177 and carry the highest concentration of MBUX infotainment glitches (screen freezes, reboots) and 7G-DCT low-speed jerkiness reported by owners and the motoring press, before Mercedes rolled out software fixes and running changes.
Known faults — Mercedes-Benz A-Class W177 (2018–present)
How to read this list. This model’s DVSA safety recalls are listed in their own section below, largest first, each with DVSA’s reference and vehicle count. Everything else in this list is owner-reported: patterns that come up repeatedly with workshops, owner forums and reliability surveys. Those are worth checking on a viewing, but we hold no count of how many cars have each one, other than any survey share a card itself quotes. Treat an owner-reported item as a question to ask, not a fault this car has.
7G-DCT dual-clutch automatic gearbox
- Symptoms
- Jerky or hesitant take-up from a standstill, a noticeable clunk or thud when selecting Drive, Reverse or Neutral (worse when the car is cold), delayed engagement, and in more serious cases a warning message with the transmission dropping into limp mode.
- Years affected
- Most commonly reported on 2018-2020 cars, though clutch-pack and mechatronic wear can appear on any W177 as mileage builds — Wear-related reports increase from roughly 50,000-70,000 miles, though software-related jerkiness can show up on much lower-mileage cars
- Indicative repair (UK)
- £150-£300 for a software update/adaptation reset if it's a mapping issue; £1,000-£1,800 for a clutch pack at an independent specialist; £1,500-£2,500+ for a replacement mechatronic unit, more again at a main dealer
- What to check before buying
- Drive the car from cold and pull away repeatedly at low speed feeling for shudder or a delayed bite; select R and D back-to-back and listen for a loud clunk; ask for a full transmission service history showing genuine MB 236.21-spec fluid changes rather than a skipped 'lifetime fluid' claim.
MBUX infotainment and electrical systems
- Symptoms
- Central and/or driver display freezing, going black, or rebooting on its own; Bluetooth dropping out; occasional loss of the reversing camera or parking sensor display; warning lights appearing without a genuine underlying fault.
- Years affected
- Heavily concentrated on 2018-2019 launch cars; reports dropped off significantly from around 2020 as software and running changes were introduced — Can appear at any mileage since most cases are software-related rather than wear-related
- Indicative repair (UK)
- Often free or low-cost as a dealer software/firmware update; £300-£500 to replace a faulty display data cable; £600-£1,200+ for a replacement head unit or screen module if the hardware itself has failed
- What to check before buying
- Cycle through every infotainment menu, pair a phone via Bluetooth, and confirm the reversing camera and parking sensor display work correctly; ask whether the car has had any MBUX-related software updates applied by a dealer.
Diesel particulate filter (DPF) blocking
- Symptoms
- DPF or exhaust system warning light, reduced power or a 'see owner's manual' message, and a noticeable smell or extra exhaust smoke during a forced regeneration; most common on cars used mainly for short, low-speed urban journeys.
- Years affected
- Applies across A180d/A200d diesel models throughout the W177 range, 2018-2025 — Not strictly mileage-linked — on a car used mostly for short trips it can appear well under 30,000 miles, while a diesel with regular motorway miles may never show it
- Indicative repair (UK)
- Free if caught early by driving for 15-20 minutes at sustained motorway speed to complete a regeneration; £100-£250 for a professional forced regen or clean; £1,000-£1,800 for a replacement DPF if the warning has been ignored for a long period
- What to check before buying
- Ask how the car is normally driven (short urban trips versus regular longer runs), check the service history for any DPF-related warnings or replacements, and take it for a test drive long enough to see a regeneration cycle behave normally.
AdBlue/SCR (diesel exhaust fluid) system
- Symptoms
- 'AdBlue system fault, see owner's manual' warning, dosing pump or tank heater faults, and — if left unresolved — a countdown to the engine refusing to restart once AdBlue is exhausted or the system logs a fault.
- Years affected
- Diesel (A180d/A200d) models across the range, most commonly reported on 2019-2022 cars — Typically reported from around 40,000-60,000 miles, or on cars that have sat unused for long periods between drives
- Indicative repair (UK)
- £20-£40 to simply top up the AdBlue tank; £300-£600 for a sensor or tank heater element; £600-£1,000+ for a dosing pump or injector replacement
- What to check before buying
- Check the dashboard for any current or recently-cleared AdBlue warnings, confirm AdBlue top-ups appear on the service record, and ask the seller directly whether the warning has ever shown.
1.3-litre turbo petrol carbon build-up and turbo actuator (A180/A200)
- Symptoms
- Rough or lumpy idle, hesitation or misfiring under load, sluggish turbo response, and in more serious cases a reduced-power or limp-mode warning caused by the electronic turbo actuator sticking.
- Years affected
- 1.3-litre turbo petrol A180/A200 models across the W177 range, particularly cars used mainly for short journeys — Most commonly reported from around 50,000-70,000 miles
- Indicative repair (UK)
- £200-£400 for a carbon clean (walnut blasting) of the intake valves; £300-£600 to free or replace a sticking turbo actuator; £1,000+ for a full turbo replacement in severe cases
- What to check before buying
- Listen for a rough idle on a cold start, check for hesitation under hard acceleration, and ask whether the car has had regular longer runs rather than exclusively short urban trips.
Electric parking brake
- Symptoms
- 'Parking brake malfunction' warning, the brake failing to release or engage on demand, or an intermittent fault that clears itself after restarting the car.
- Years affected
- Reported across the W177 range, with a higher concentration on 2018-2020 cars — No strong mileage link — often tied to the age/condition of the 12V battery rather than miles covered
- Indicative repair (UK)
- Frequently resolved by a battery check/replacement (£150-£250); £150-£400 for a parking brake actuator; more if the control module itself needs replacing
- What to check before buying
- Apply and release the parking brake several times with the engine running, and check the age and health of the 12V battery, since a weak battery is a common trigger for this warning.
DVSA safety recalls for the Mercedes-Benz A-Class, largest first
These are the recalls DVSA lists for this model and its build years: every one of 10,000 or more vehicles, largest first, with DVSA’s own reference and figures. A recall covers only cars built in its dates and within its VIN range — check a particular car by registration through GOV.UK’s vehicle recall check. “Critical” here means DVSA’s own notice tells owners not to drive the car until it is fixed. It is never a size: “Large” means DVSA lists 10,000 or more vehicles in the recall.
- Safety recall · R/2024/166Large recall — 182,919 vehicles
Backup function of steering software
On affected vehicles the backup function of the steering software might not meet specifications. As a result the steering power support might be impaired and a loss of steerability cannot be ruled out.
182,919 vehicles of this model (DVSA’s figures added up) · built between 25 January 2018 and 2 February 2024 · recall launched 6 May 2024
- Safety recall · R/2021/134Large recall — 162,581 vehicles
The behaviour of the emergency call system might not meet specifications
162,581 vehicles in the whole recall (DVSA’s figure for every model it covers) · built between 4 January 2016 and 29 January 2021 · recall launched 5 May 2021
- Safety recall · R/2021/110Large recall — 108,971 vehicles
The behaviour of the emergency call system might not meet specifications
108,971 vehicles in the whole recall (DVSA’s figure for every model it covers) · built between 4 January 2016 and 29 January 2021 · recall launched 13 May 2021
- Safety recall · R/2021/133Large recall — 106,665 vehicles
The emergency call system might not meet specifications
106,665 vehicles in the whole recall (DVSA’s figure for every model it covers) · built between 4 January 2016 and 29 January 2021 · recall launched 5 May 2021
- Safety recall · R/2021/111Large recall — 90,716 vehicles
The behaviour of the emergency call system might not meet specifications
90,716 vehicles in the whole recall (DVSA’s figure for every model it covers) · built between 4 January 2016 and 29 January 2021 · recall launched 10 May 2021
- Safety recall · R/2021/120Large recall — 86,604 vehicles
The behaviour of the emergency call system might not meet specifications
86,604 vehicles in the whole recall (DVSA’s figure for every model it covers) · built between 4 January 2016 and 29 January 2021 · recall launched 11 May 2021
5 more recalls of 10,000+ vehicles
- Safety recall · R/2021/131Large recall — 81,267 vehicles
The behaviour of the emergency call system might not meet specifications
81,267 vehicles in the whole recall (DVSA’s figure for every model it covers) · built between 4 January 2016 and 29 January 2021 · recall launched 5 May 2021
- Safety recall · R/2021/376Large recall — 50,390 vehicles
The behaviour of the emergency call system might not meet specifications
50,390 vehicles in the whole recall (DVSA’s figure for every model it covers) · built between 4 January 2016 and 29 January 2021 · recall launched 29 November 2021
- Safety recall · R/2020/221Large recall — 20,536 vehicles
The air conditioning drain hose may be incorrectly installed
20,536 vehicles of this model (DVSA’s figures added up) · built between 25 January 2018 and 10 February 2019 · recall launched 30 September 2020
- Safety recall · R/2021/119Large recall — 16,122 vehicles
The behaviour of the emergency call system might not meet specifications
16,122 vehicles of this model (DVSA’s figures added up) · built between 4 January 2016 and 29 January 2021 · recall launched 12 May 2021
- Safety recall · R/2021/132Large recall — 10,410 vehicles
The behaviour of the emergency call system might not meet specifications
10,410 vehicles in the whole recall (DVSA’s figure for every model it covers) · built between 4 January 2016 and 29 January 2021 · recall launched 5 May 2021
Source: DVSA vehicle recalls file (every recall since 1992), published under the Open Government Licence. Where DVSA gives one figure for a recall that covers several models, it is shown as the whole recall’s total.
Mercedes-Benz A-Class MOT results by year and mileage
Measured from DVSA’s own MOT test records for tests carried out in 2025, not from owner reports.
By registration year
Against all cars registered in the same year, the MOT pass rate for the A-Class was higher in 2 and level in 8 of the 10 registration years from 2013 to 2022 with enough tests to measure. The widest gap above is 2013 registrations: 75.0% against 71.9%.
| Registered | A-Class | All cars that year | Difference |
|---|---|---|---|
| 20221,748 tests | 92.3% | 91.2% | +1.1 level |
| 20212,869 tests | 91.8% | 90.1% | +1.7 higher |
| 20203,606 tests | 89.1% | 88.7% | +0.4 level |
| 20195,353 tests | 87.7% | 86.9% | +0.8 level |
| 20184,420 tests | 85.0% | 84.5% | +0.5 level |
| 20174,430 tests | 82.1% | 82.2% | −0.1 level |
| 20164,148 tests | 78.4% | 79.4% | −1.0 level |
| 20152,936 tests | 76.8% | 76.7% | +0.1 level |
| 20142,471 tests | 74.3% | 74.3% | 0.0 level |
| 20131,640 tests | 75.0% | 71.9% | +3.1 higher |
By mileage at the test
Against cars of the same age on the same mileage, the pass rate for the A-Class was higher in 2 and level in 3 of the 5 mileage bands with enough tests. How other models compare at the same mileage.
Show the table by mileage (5 bands)
| Mileage | A-Class | Same age and mileage | Difference |
|---|---|---|---|
| 20k–40k7,339 tests | 89.5% | 89.1% | +0.4 level |
| 40k–60k10,025 tests | 84.6% | 83.6% | +1.0 higher |
| 60k–80k8,705 tests | 80.2% | 78.3% | +1.9 higher |
| 80k–100k5,732 tests | 74.4% | 73.8% | +0.6 level |
| 100k–120k2,573 tests | 70.7% | 70.7% | −0.1 level |
Only a major or dangerous defect fails an MOT. A minor defect is recorded on the certificate and the car still passes, and an advisory is not a failure at all.
We don’t give a recall count for the Mercedes-Benz A-Class: whether a recall applies depends on the individual car. Check the one you are looking at by entering its registration on GOV.UK’s vehicle recall checker, and see how to check a car for known faults for the other free checks.
Source: DVSA MOT Anonymised Data 2025 (Open Government Licence v3.0). Class 4 tests in Great Britain, test type NT (a normal annual test), retests excluded. A pass, or a pass with rectification at the station, counts as a first-time pass; DVSA's own initial-test measure counts a rectified pass as a failure and so reports a lower figure. Odometer readings below 100 or above 400,000 miles are discarded as misreadings, and cars under three years old are excluded because no MOT is yet due. Sampled from nine months of 2025 (January, February, April, May, July, August, September, October and November). Testing in Northern Ireland is run separately by the DVA under its own rules. Registration years shown are cars 3 to 12 years old when tested; the smallest rests on 1,640 tests. A gap is called level when it is under one percentage point or inside the 95% sampling margin for that number of tests. Contains public sector information licensed under the Open Government Licence v3.0.
Who this car suits — and who should look elsewhere
Buyers wanting the most premium-feeling interior in this class, especially the MBUX infotainment. A 2021+ car with confirmed DCT service history is the safer buy for the automatic.
Anyone considering the 7G-DCT automatic without documented gearbox oil/filter change history — this is the highest-risk combination on the car. Buyers wanting maximum rear legroom, which is tight for the class.
Alternatives to consider
If the Mercedes-Benz A-Class doesn't suit, these comparable models are worth a look in the UK market:
Mercedes-Benz A-Class: questions buyers ask
What are the most common faults on a used Mercedes-Benz A-Class in the UK?
The Mercedes-Benz A-Class W177 (2018–present) is a premium hatchback rivalling the Audi A3 and BMW 1 Series. The key check is the 7G-DCT dual-clutch gearbox: drive it from cold, feel for jerky take-up, and look for transmission fluid changes in the history. Launch-year 2018–2019 cars carry the most MBUX and DCT complaints. Best buy: 2023–2025 facelift.
What is the best year to buy a used Mercedes-Benz A-Class in the UK?
Best-buy years: 2023, 2024, 2025. The 2023–2025 facelifted W177 benefits from several years of dealer software updates to MBUX, revised DCT clutch/software mapping, and production running changes that addressed the electrical and gearbox complaints most commonly reported on early cars, making these the safer years to buy on reliability grounds.
What years of Mercedes-Benz A-Class should I avoid in the UK?
Worst years: 2018, 2019. 2018 and 2019 were the UK launch years for the W177 and carry the highest concentration of MBUX infotainment glitches (screen freezes, reboots) and 7G-DCT low-speed jerkiness reported by owners and the motoring press, before Mercedes rolled out software fixes and running changes.
How much does a used Mercedes-Benz A-Class cost in the UK in 2026?
What sellers were asking on Autoza on 16 October 2026, for Mercedes-Benz A-Class cars registered from 2018: £10,495–£27,995, median £13,495 — the range is the middle 80% of asking prices. Those are asking prices, not what buyers paid, and not a UK price index. Prices vary by mileage, region and trim, so compare several adverts of the same year and mileage band before negotiating.
What is the road tax (VED) on a Mercedes-Benz A-Class in the UK?
Annual road tax (VED): £200/year standard rate from the second year, hybrids included — the alternative-fuel discount ended on 1 April 2025 (2026/27 rates). A car registered from April 2017 that listed at over £40,000 new (options included) also pays the £440/year Expensive Car Supplement in years 2–6 — it is the price when new that counts, not what you pay for it used.
What real-world fuel economy does a Mercedes-Benz A-Class achieve on UK roads?
Typical real-world consumption: A180d diesel: 55–62 mpg. A180/A200 petrol: 40–46 mpg. A250e PHEV: 20–28 miles electric range, 35–45 mpg once depleted.
How does a Mercedes-Benz A-Class compare to its rivals?
Strong alternatives in the UK: Audi A3, BMW 1 Series, Volkswagen Golf, Volvo V40. Choose based on dealer network in your area, parts availability, and your priorities (running cost vs. cabin quality vs. badge).
Who is the Mercedes-Benz A-Class most suitable for?
Buyers wanting the most premium-feeling interior in this class, especially the MBUX infotainment. A 2021+ car with confirmed DCT service history is the safer buy for the automatic.
Who should NOT buy a Mercedes-Benz A-Class?
Anyone considering the 7G-DCT automatic without documented gearbox oil/filter change history — this is the highest-risk combination on the car. Buyers wanting maximum rear legroom, which is tight for the class.
Are there safety recalls on the Mercedes-Benz A-Class?
DVSA lists 11 safety recalls for the Mercedes-Benz A-Class that this guide shows or names, the largest first: R/2024/166 (182,919 vehicles, built between 25 January 2018 and 2 February 2024): Backup function of steering software; R/2021/134 (162,581 vehicles in the whole recall, built between 4 January 2016 and 29 January 2021): The behaviour of the emergency call system might not meet specifications; R/2021/110 (108,971 vehicles in the whole recall, built between 4 January 2016 and 29 January 2021): The behaviour of the emergency call system might not meet specifications. Whether a particular car is affected depends on its build date and VIN, so check its registration on GOV.UK (gov.uk/check-vehicle-recall) before you buy.
Is the 7G-DCT dual-clutch automatic gearbox on the Mercedes-Benz A-Class a serious problem?
Owner-reported, frequency unknown: 7G-DCT dual-clutch automatic gearbox comes up in owner forums and workshop reports for the Mercedes-Benz A-Class, but how often it happens is not known, so treat it as a question to ask rather than a fault every car has. Symptoms: Jerky or hesitant take-up from a standstill, a noticeable clunk or thud when selecting Drive, Reverse or Neutral (worse when the car is cold), delayed engagement, and in more serious cases a warning message with the transmission dropping into limp mode. Years affected: Most commonly reported on 2018-2020 cars, though clutch-pack and mechatronic wear can appear on any W177 as mileage builds. Wear-related reports increase from roughly 50,000-70,000 miles, though software-related jerkiness can show up on much lower-mileage cars. Indicative repair cost in the UK: £150-£300 for a software update/adaptation reset if it's a mapping issue; £1,000-£1,800 for a clutch pack at an independent specialist; £1,500-£2,500+ for a replacement mechatronic unit, more again at a main dealer. What to check before buying: Drive the car from cold and pull away repeatedly at low speed feeling for shudder or a delayed bite; select R and D back-to-back and listen for a loud clunk; ask for a full transmission service history showing genuine MB 236.21-spec fluid changes rather than a skipped 'lifetime fluid' claim.
Is the Diesel particulate filter (DPF) blocking on the Mercedes-Benz A-Class a serious problem?
Owner-reported, frequency unknown: Diesel particulate filter (DPF) blocking comes up in owner forums and workshop reports for the Mercedes-Benz A-Class, but how often it happens is not known, so treat it as a question to ask rather than a fault every car has. Symptoms: DPF or exhaust system warning light, reduced power or a 'see owner's manual' message, and a noticeable smell or extra exhaust smoke during a forced regeneration; most common on cars used mainly for short, low-speed urban journeys. Years affected: Applies across A180d/A200d diesel models throughout the W177 range, 2018-2025. Not strictly mileage-linked — on a car used mostly for short trips it can appear well under 30,000 miles, while a diesel with regular motorway miles may never show it. Indicative repair cost in the UK: Free if caught early by driving for 15-20 minutes at sustained motorway speed to complete a regeneration; £100-£250 for a professional forced regen or clean; £1,000-£1,800 for a replacement DPF if the warning has been ignored for a long period. What to check before buying: Ask how the car is normally driven (short urban trips versus regular longer runs), check the service history for any DPF-related warnings or replacements, and take it for a test drive long enough to see a regeneration cycle behave normally.
Is the AdBlue/SCR (diesel exhaust fluid) system on the Mercedes-Benz A-Class a serious problem?
Owner-reported, frequency unknown: AdBlue/SCR (diesel exhaust fluid) system comes up in owner forums and workshop reports for the Mercedes-Benz A-Class, but how often it happens is not known, so treat it as a question to ask rather than a fault every car has. Symptoms: 'AdBlue system fault, see owner's manual' warning, dosing pump or tank heater faults, and — if left unresolved — a countdown to the engine refusing to restart once AdBlue is exhausted or the system logs a fault. Years affected: Diesel (A180d/A200d) models across the range, most commonly reported on 2019-2022 cars. Typically reported from around 40,000-60,000 miles, or on cars that have sat unused for long periods between drives. Indicative repair cost in the UK: £20-£40 to simply top up the AdBlue tank; £300-£600 for a sensor or tank heater element; £600-£1,000+ for a dosing pump or injector replacement. What to check before buying: Check the dashboard for any current or recently-cleared AdBlue warnings, confirm AdBlue top-ups appear on the service record, and ask the seller directly whether the warning has ever shown.
Check these next
The guide above is about the Mercedes-Benz A-Class as a model. These are about the car in front of you.
- Browse Mercedes-Benz A-Class listings on AutozaEvery one listed now.
- Check any car by its registrationFree: its MOT history, tax status and any open recall, from a number plate.
- Work out the road tax for the A-ClassVehicle tax (VED) by registration date, CO2 and list price.
- Work out the monthly payment on a £13,495 A-ClassThe median asking price on Autoza on 16 October 2026, not what buyers pay: change it to the car you are looking at.
- What is your A-Class worth?A price range from dealers' asking prices for comparable cars.
Looking to buy a Mercedes-Benz A-Class in the UK?
Search Autoza listings filtered by year, mileage, and region. Every dealer page shows the business name, address and contact details, so you can check the business before you enquire.