Buying Guide / 2013–2024

Mercedes-Benz CLA Problems & Buying Guide

Four-door coupe style meets premium badge appeal

1.3–2.1L
Engines
2
Generations
5
Known Issues
284k
MOT Tests

The CLA bridges the gap between A-Class hatchback and C-Class saloon, offering swoopy coupe styling from around £10,000 for early C117 models to £25,000+ for facelifted C118s. Strong UK demand for the AMG Line trim keeps residuals firm. Rivals include the BMW 2 Series Gran Coupe and Audi A3 Saloon, but the CLA's design-led appeal gives it an edge in the premium compact four-door segment.

We track 5 known issues across the Mercedes-Benz CLA range, with 2 classified as significant. Knowing which variants and configurations to approach with caution can save you from expensive surprises after purchase.

Found a Mercedes-Benz CLA? Enter the reg to see which of our 5 known issues apply to that exact car, plus full MOT history and mileage checks.

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History & Generations

C117 (2013–2019) — Petrol options included the 1.6 Turbo, 2.0 Turbo, with 1.8 CDI, 2.1 CDI on the diesel side. We track 5 known issues on this generation, with 2 classified as significant. The most significant concern is Excessive brake pad wear (£150–£400 to address).

C118 (2019–2024) — Petrol options included the 1.3 Turbo, 2.0 Turbo, with 2.1 CDI on the diesel side. We track 5 known issues on this generation, with 2 classified as significant. The most significant concern is Excessive brake pad wear (£150–£400 to address).

5 Things to Know Before You Buy
1
Excessive brake pad wear
High £150–£400 C117, C118

MOT data shows CLA models fail brake pad thickness tests at up to 15.3 times the national fleet average, particularly on 1.6-litre petrol variants at low mileage. The issue affects all engine variants and appears across all mileage bands from new cars to high-mileage examples. This suggests either undersized brake components for the vehicle weight, aggressive pad compounds, or brake system design issues causing uneven pad wear patterns.

Brake pads worn to metal backing plates will score brake discs requiring expensive disc replacement alongside pad renewal. Complete brake failure is possible if pads wear through entirely. Typical pad and disc replacement costs £400-800 depending on whether front axle only or full vehicle renewal is required.

What to check

Check brake disc condition for lipping or scoring. Test braking at moderate speed for pulling to one side or vibration through the steering wheel. Review MOT advisories for brake-related items.

Sources: Honest John, What Car?, Auto Express, owner forums, specialist workshops
2
Brake fluid loss
High £200–£500 C117, C118

MOT data shows CLA models fail brake fluid level tests at up to 11.5 times the national fleet average, particularly affecting 1.3-litre petrol variants in the 40,000-60,000 mile range. This pattern suggests either brake system leaks developing at specific service intervals, brake caliper seal degradation, or brake fluid consumption through normal pad wear being unusually high on this model.

Low brake fluid reduces braking performance and can lead to complete brake system failure. Air entering the brake system through leaks causes spongy pedal feel and extended stopping distances. Brake system repair costs typically range from £200-600 depending on whether the issue is brake line corrosion, caliper seal failure, or master cylinder problems.

What to check

Check brake disc condition for lipping or scoring. Test braking at moderate speed for pulling to one side or vibration through the steering wheel. Review MOT advisories for brake-related items.

Sources: Honest John, What Car?, Auto Express, owner forums, specialist workshops
3
Suspension joint dust cover deterioration
Minor £150–£300 C117, C118

MOT data shows CLA models fail suspension dust cover tests at up to 7.2 times the national fleet average, particularly affecting 2.1-litre diesel variants from 20,000 miles onwards. The failures span all mileage ranges from 20,000 miles to 150,000+ miles, suggesting either poor-quality rubber compounds in the dust covers or suspension geometry that places unusual stress on the protective boots covering ball joints and bushes.

Failed dust covers allow road dirt and water to contaminate suspension joints, leading to accelerated wear and eventual joint failure. While not immediately dangerous, contaminated joints will require replacement within 12-24 months rather than lasting their normal service life. Ball joint replacement typically costs £200-400 per corner.

What to check

Listen for knocking, clunking or rattling over bumps during the test drive. Inspect the underside for corroded or cracked suspension components. Check the MOT history for suspension-related advisories, which often predict future failures.

Sources: Honest John, What Car?, Auto Express, owner forums, specialist workshops
4
Engine management light illumination
Minor £80–£1,500 C117, C118

The pattern affects all mileage bands including new cars, suggesting emissions system faults rather than wear-related issues. Common causes on Mercedes diesels include DPF regeneration problems, NOx sensor failures, and EGR valve carbon build-up.

An illuminated engine management light causes automatic MOT failure. Underlying faults can include expensive DPF problems (£1,500-3,000 replacement), NOx sensor failures (£300-600), or EGR valve issues (£400-800). Some faults may trigger engine protection modes reducing power output.

What to check

Check all electrical functions systematically: windows, mirrors, lights, infotainment, heated seats, air conditioning. Look for any warning lights on the dashboard. A diagnostic scan before purchase can reveal stored fault codes.

Sources: Honest John, What Car?, Auto Express, owner forums, specialist workshops
5
Brake disc wear
Minor £200–£500 C117, C118

MOT data shows CLA models fail brake disc thickness tests at 3.3 times the national fleet average, with 1.8-litre diesel variants particularly affected at 80,000-100,000 miles. The issue spans all engine variants and mileage bands, correlating with the documented excessive brake pad wear on this model. Accelerated disc wear suggests either inadequate brake disc specifications for vehicle weight or brake system design issues causing excessive heat generation.

Worn brake discs beyond minimum thickness cause MOT failure and compromise braking performance. Severely worn or warped discs require replacement rather than skimming. Combined brake disc and pad renewal typically costs £300-600 per axle depending on disc size and quality.

What to check

Check brake disc condition for lipping or scoring. Test braking at moderate speed for pulling to one side or vibration through the steering wheel. Review MOT advisories for brake-related items.

Sources: Honest John, What Car?, Auto Express, owner forums, specialist workshops

For the full breakdown of all 5 tracked issues with repair costs, see the Mercedes-Benz CLA common problems page.

MOT Weak Points

Based on 284k real DVSA MOT tests, the Mercedes-Benz CLA fails more often than average on several items. The biggest outlier is any fracture or welding defect on a wheel at 39x the fleet average, followed by wheel with a loose or missing wheel nut, bolt o... (22x).

When viewing a specific car, check its MOT history for recurring advisories in these categories. See the full Mercedes-Benz CLA MOT failure breakdown for data at every mileage point.

Running Costs

Routine servicing (oil and filter change every 10k miles) typically costs £120–£180 at an independent garage.

See the full Mercedes-Benz CLA service schedule for every interval and cost breakdown.

The Verdict

The Mercedes-Benz CLA is a reasonable used buy provided you check for the issues outlined above. None of the problems we track are insurmountable, but they do reward buyers who inspect thoroughly and verify the service history before committing. 2020-2023 C118 models are the sweet spot — the revised MBUX system is more polished, the 1.3 turbo petrol (M282) and 2.0 diesel (OM654) are proven units, and early C118 depreciation has settled. Avoid 2022 specifically (lowest reliability score at 38/100). For the older C117, 2016-2019 facelifted cars had improved 7G-DCT calibration and fewer electrical issues than 2013-2015 pre-facelift models.

Before committing, check the car's full MOT history, verify the service record is complete, and if possible arrange a specialist inspection. Enter any registration into our free report to see the complete picture.

The good
  • Striking coupe-like design stands out against conventional compact saloon rivals
  • MBUX infotainment on C118 models is class-leading with voice control and widescreen cockpit
  • CLA 35 and CLA 45 AMG variants offer serious performance from 306bhp to 421bhp
  • 2.0 diesel (OM654) returns 55-60mpg and covers motorway miles effortlessly
Watch out for
  • Excessive brake pad wear
  • Brake fluid loss
  • Suspension joint dust cover deterioration
  • Engine management light illumination
Why Check With Get Car Wise?

Get Car Wise maintains a database of known mechanical issues for every popular car on UK roads, tracking the faults that owners, specialists and DVSA data reveal.

When you run a report on a specific Mercedes-Benz CLA, we cross-reference the exact variant, engine and age against our database of 5 known issues. Combined with full MOT history analysis, mileage verification and DVLA data, you get a complete picture before viewing.

Found a Mercedes-Benz CLA?

Enter the registration for MOT history, mileage verification, known faults for that exact variant, and a Get Car Wise Score.

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Sources & Further Reading

This guide was compiled from independent expert reviews, DVSA MOT data, specialist workshops and our own database of 5 known Mercedes-Benz CLA issues. We are not affiliated with any source listed.