There are 3 owner-reported powertrain & transmission complaints for the 2023 Mercedes-Benz GLC-Classin NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
Vehicle sputter and coolant malfunction and engine light came on while driving ( 12-26-23) Took to dealer for some “ update”. After a few weeks of driving the vehicle sputter again and engine light came on again on the (1-19-2024 ) Drove home turned off , loud noises came from engine area. Tried to restart and failed a few times so we let it’s sit for almost an hour and it’s started again with engine light still on . Towed to Mercedes dealer and after long and frustrating times a week later per dealer it’s was the 48v hybrid battery that defective/ non functional. So far we been forced to drive the vehicle “as is” since Mercedes-Benz USA refused to let local dealer to order and replace the 48v hybrid battery. It’s been 2 weeks all informations we get from dealership is that we have to wait for Mercedes to come up with new software to update to which no time frame have been provided as to when software available. We’re experiencing terrible gas mileage MPG with the 48v battery basically non functional as moment
VEHICLE SHUT DOWN WHILE DRIVING. WARNING LIGHTS ILLUMINATE, CHECK ENGINE LIGHT, DO NOT SHIFT INTO GEAR WARNING, 48V BATTERY WARNING, ETC. WOULD NOT STOP ALARMING. COULD NOT SHUT OFF CAR. COULD NOT PUT CAR INTO PARK. COULD NOT START CAR. WARNING BUZZER WOULD GO OFF ENTIRE TIME. CAR WAS ONLY ABLE TO BE STARTED WHEN REMOTE START REQUEST WAS INITIATED WHEN CAR WAS IN THIS MODE, CAR WAS STARTED BUT THEN SHUT OFF 10 SECONDS LATERS APP STATES, “CHECK ENGINE LIGHT ON” WIL SHUT OFF THE CAR. CAR BACK TO NORMAL AFTER EVENT APPROX 60 MIN BUT CHECK ENGINE LIGHT REMAINS ON.
The 2023 GLC300 would not start. The internal alarms kept going off, the push-start/stop would not respond. The vehicle was acting like it was being stolen, this lasted for 75 to 80 minutes. The display said 12V On-Board Electrical System Service Required and Blind Spot Assist Inoperative - over and over again. Couldn't get the key to make car lock or unlock. The car would not turn on, it would not turn off. The alarm message was persistent. Had to call a tow-truck to take it in for service. After 3+ hours the car restarted. Mercedes initiated "Campaign: Update Powertrain Control Unit Software #2023060007". They found multiple communication faults in various modules. I was left stranded. This happened 3 times. Twice in front of the house and the 3rd time (when it was towed) I was far from home. The mechanic explained that the car had sensors indicating the car was being stolen so that is why it didn't start. That make no sense! I had the key. I had been driving it that day. It was working fine. A brand new 2023 car should be reliable. It should start when the owner has the key fob in hand. Shutting the car down for hours is a system failure. Please investigate.
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