Generations
X156 — First Generation GLA-Class
2014–2020
GLA 200, GLA 250, GLA 220 CDI/d
Top issues to watch for
The most serious Mercedes Benz Gla problems ranked by severity. We track 5 known issues — here are the ones you need to know about first.
Major
Excessive brake fluid consumption
The GLA shows abnormally high rates of brake fluid falling below minimum levels, with MOT data showing failures at 9.5x the fleet average on some variants. This suggests either external leaks from brake lines or internal consumption through worn brake components. The issue affects cars from new, indicating a design or manufacturing concern rather than normal wear. Low brake fluid triggers ESP and ABS warning lights and can lead to brake system failure.
What happens if ignoredBrake system failure can occur without warning if fluid levels become critically low. External leaks typically require brake line replacement at £300-600. Internal consumption may indicate master cylinder or brake servo issues costing £800-1500. The car should not be driven if brake fluid levels cannot be maintained.
Independent garage
£300–£800
Specialist
£400–£1,200
Main dealer
£600–£1,800
Parts only
£100–£400
Minor
Suspension joint dust cover deterioration
The GLA suffers premature deterioration of suspension joint dust covers, with failures at 7.8x the fleet average. These rubber boots protect ball joints and track rod ends from dirt and water ingress. When they split or detach, contamination accelerates joint wear and leads to MOT failures. The issue affects multiple suspension components across all engine variants and appears to worsen over time, suggesting material quality concerns.
What happens if ignoredSplit dust covers allow contamination of suspension joints, leading to premature wear and eventual joint replacement at £200-400 per side. This is primarily an MOT failure issue rather than a safety concern, but neglected joints will require more expensive replacement rather than simple cover renewal.
Independent garage
£80–£200
Specialist
£120–£300
Main dealer
£200–£500
Parts only
£20–£60
Minor
Premature brake pad wear
MOT data shows the GLA reaches brake pad wear indicators at 6.6x the fleet average, particularly on 1.6L petrol variants at low mileage. This suggests either aggressive brake pad compounds, insufficient cooling, or brake system imbalance causing uneven wear. The issue affects cars from very low mileage, indicating design factors rather than normal wear patterns.
What happens if ignoredWorn brake pads require replacement at £150-300 for front and rear sets. If not replaced promptly, the metal backing plates score the brake discs, requiring disc replacement at additional cost of £200-400. Completely worn pads can cause brake failure.
Independent garage
£120–£250
Specialist
£150–£300
Main dealer
£200–£450
Parts only
£60–£150
Minor
Engine management light (diesel variants)
The 2.1L diesel GLA shows engine management light failures at This typically indicates emissions system faults such as EGR valve carbon build-up, DPF regeneration problems, or lambda sensor failures. The pattern across all mileage bands suggests design vulnerabilities in the emissions control system rather than normal component wear.
What happens if ignoredEmissions system faults can cause MOT failures and reduced fuel economy. EGR valve cleaning costs £200-400, DPF regeneration or replacement £800-2000, and lambda sensor replacement £150-300. The car remains driveable but may enter reduced power mode.
Independent garage
£150–£600
Specialist
£200–£800
Main dealer
£300–£1,200
Parts only
£100–£400
1 more known issues tracked
Including wear items, electrical niggles, and generation-specific problems.
MOT failure hotspots
Based on DVSA MOT test data. These are the items where the Mercedes Benz Gla fails at a significantly higher rate than the average car.
Steering lock missing or not functioning
Steering · 80-100k miles
MOT failure rate: 11x the fleet average
Sample: 10,391 tests
Anti-roll bar links worn
Suspension · 0-20k miles
MOT failure rate: 10x the fleet average
Sample: 4,253 tests
Brake fluid below minimum mark
Brakes · 0-20k miles
MOT failure rate: 9.5x the fleet average
Sample: 18,005 tests
Transmission shaft flexible coupling deteriorated
Bodywork · 120-150k miles
MOT failure rate: 8.6x the fleet average
Sample: 1,408 tests
Tyre wear or damage
Tyres · 100-120k miles
MOT failure rate: 8.1x the fleet average
Sample: 4,296 tests
Brake fluid significantly below minimum mark
Brakes · 0-20k miles
MOT failure rate: 7.3x the fleet average
Sample: 18,005 tests
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Related
- Mercedes Benz Gla buyer's guide
- Mercedes Benz Gla service history check
- Mercedes Benz Gla service schedule & costs
- Mercedes Benz Gla MOT failure rates
- Mercedes Benz Gla price guide
- Buying a car without service history
- Mercedes Benz Gla car check £7.49
- Free car faults check
- Free MOT failure rate check
- Free car check
Mercedes Benz Gla reliability FAQs
What are the most common problems with the Mercedes Benz Gla?
The Mercedes Benz Gla has 5 known issues across 2 severity levels. The most common problems relate to Excessive brake fluid consumption.
Is the Mercedes Benz Gla reliable?
The Mercedes Benz Gla has 0 dangerous and 1 major known issues. No dangerous issues are tracked, which is a positive sign.
How much does it cost to fix Mercedes Benz Gla problems?
Repair costs range widely. The most significant issue (Excessive brake fluid consumption) costs £300–£800 at an independent garage. Minor issues can be under £200. Always get a full inspection before buying.