There are 3 owner-reported engine complaints for the 2021 Mercedes-Benz GLA-Classin NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
I recently purchased my vehicle with under 30k miles in July of 2026. Not long after my purchase my car began roughly idling with a blinking check engine light, and soon after the engine began misfiring. This also cause loss of power when attempting to accelerate creating dangerous conditions in high traffic/fast paced areas. After lots of research I found several reports of owners with cylinder failures. The dealership only responded to fixing the issue after calling them out directly on the issue.
I purchased this car approx 3 months after real issues began. My car would have issues idling where it would sometimes turn off at stop lights and require multiple reignition attempts before proceeding. This would also happen when the auto-start feature (anti-idle/gas saving) was engaged (which is the default in the system) and this posed major safety concerns. The unstable idling of the car would result in an initial acceleration after being stopped, shortly followed by the engine dying. There were multiple times I was at an intersection yielding before turning where this happened and it resulted in my being in the path of oncoming traffic without the ability to accelerate until the car restarted. I contacted my local Mercedes dealer who acted like this wasn't a big deal, but it is related to a known issue with a faulty cylinder head. They covered the repair under the manufacturer warranty, but told me to keep driving my car and promised it was safe until they could get the part in (because the didn't have a loaner car to provide). I found this very troubling. In conversations throughout the repair being completed, the dealer admitted that they know the part that was used for the year and model is bad, but they didn't want to do a recall and would wait for issues to come up. This is unacceptable because this absolutely is a safety concern as demonstrated by the example I shared. They should be required to do a full recall to address the safety concerns and I believe not disclosing this information was unfair to me as a consumer who did not have the information I needed to be informed on the reliability of this vehicle prior to purchase.
Engine misfired in operation requiring an emergency stop while on a mountain road. Severe check engine light turned on (Mercedes has a two stage check engine light). Vehicle was parked for 20 minutes and battery was disconnected. This appeared to fix the issue. Vehicle was brought to dealer. Dealer stated the cylinder head for early 2021 GLA 250 engines had a casting flaw that result in hot gases escaping and damaging engine. Engine and turbo rebuilt under warranty at 17000 miles.
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 25, 2026