Mercedes-Benz · Known Issues
2021 Mercedes-Benz GLA Problems: 9 Known Issues
2021 model year · 500+ owner reports · Updated September 2026
2021 · All trims · All engines
Choose the year and equipment for your written issues and visual request.
2021 model year · 500+ owner reports · Updated September 2026
2021 · All trims · All engines
Choose the year and equipment for your written issues and visual request.
Interest applies to the selected vehicle and configuration; it is not a reservation. Voting stores a first-party identifier for up to 180 days to prevent repeat votes. No account or email is needed. Clearing cookies or using another device may count separately. Privacy
Visual coming soon
Your interest helps us choose what to build next.
Visual Known Issues · Coming soon
$4.99/month plus taxes at launch · No payment today
According to Au7o's analysis of 500+ owner reports, the 2021 Mercedes-Benz GLA has 9 documented known issues, with 1 rated critical. The most serious is Diesel EGR/DPF Clogging & AdBlue (SCR) System Faults (OM651/OM654) ($300-$2,500 repair). The most commonly reported issue is Transfer Case Noise (AWD Models) with 500 owner reports. Across all issues with published estimates, repair costs range from $120 to $2,800. DIY maintenance guides at au7o.io.
Don't see your problem? Describe your symptoms to get a diagnosis, or get a full repair guide.
According to Au7o's analysis of 500+ owner reports, the 2021 Mercedes-Benz GLA has 9 documented issues. The most frequently reported are: Diesel EGR/DPF Clogging & AdBlue (SCR) System Faults (OM651/OM654), Transfer Case Noise (AWD Models), MBUX/COMAND Infotainment Black Screen & Reboot (NHTSA Recall 21V354). Of these, 1 is rated critical and should be addressed promptly.
The 2021 Mercedes-Benz GLA has 9 known issues documented across 500+ owner reports. 1 issue is rated critical: Diesel EGR/DPF Clogging & AdBlue (SCR) System Faults (OM651/OM654). Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.
Repair costs for known Mercedes-Benz GLA issues range from $0 to $2,800, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, Diesel EGR/DPF Clogging & AdBlue (SCR) System Faults (OM651/OM654), typically costs $300-$2,500 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
GLA diesels (GLA 200d/220d), popular in Germany and the EU, develop clogged EGR valves and diesel particulate filters from soot buildup, plus AdBlue/SCR (NOx reduction) faults. EGR carbon fouling causes rough idle, reduced power and emissions faults; DPF blockage triggers limp mo… Repairs typically run $300-$2,500. Severity: high.
The 4MATIC transfer case on the GLA develops a whining or humming noise at highway speeds. The noise is caused by gear wear inside the power take-off unit that distributes torque to the rear axle. More common on vehicles that have seen off-road use or aggressive driving. Repairs typically run $200-$2,000. Severity: medium.
Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.
GLA infotainment units suffer black/frozen screens and spontaneous reboots. On H247 cars this is the NVIDIA-Tegra-based MBUX head unit, which can fail to boot or reboot ~50 seconds after startup, disabling the rearview camera image (the basis of NHTSA recall 21V354 covering 2019-… Repairs typically run $0-$1,500. Severity: medium.
H247 GLA owners report the air conditioning failing to cool properly in hot weather while the system makes an unusually loud droning or rattling noise that rises and falls as the compressor cycles. Reported causes cluster around three things: a slow refrigerant loss that leaves t… Repairs typically run $200-$2,800. Severity: medium.
Mercedes communications directly support discharged 12V starter batteries and no-start conditions on both GLA generations. Communications 10157073, 10157076, 10158199 and 10158370 cover discharged batteries, no-start complaints and excessive quiescent current on earlier GLA vehic… Severity: medium.
On 4MATIC GLA250/GLA220d cars the rear differential carrier assembly is a documented weak point, producing whine, growl, or clunk from the rear (especially on/off throttle and cornering), often at surprisingly low mileage (~50,000-70,000 mi). The differential uses a very small fl… Repairs typically run $150-$2,500. Severity: medium.
The GLA's panoramic roof drains water through four small tubes that run down the A- and C-pillars. Pollen, grit and - in documented GLA cases - a broken plastic bracket from the sunroof track itself block the tube or the drain channel, so water backs up over the channel lip and r… Repairs typically run $120-$1,500. Severity: medium.
The positive crankcase ventilation regulator is integrated into the plastic valve cover / breather assembly on the M270 and M274 2.0T engines (and carries over in modified form on the M260). The rubber diaphragm inside the partial-load crankcase ventilation valve hardens and tear… Repairs typically run $150-$2,000. Severity: medium.
The GLA hides its reversing camera behind a motorized flap in the tailgate handle trim, which is supposed to swing open when reverse is selected and close again to keep the lens clean. The small flap motor, its position sensor, and especially the flex wiring running into the movi… Repairs typically run $150-$900. Severity: low.