2023 Mercedes-Benz GLC Reliability Report

Low beams from the Digital Light headlights reach only a short distance and show dark, jagged gaps, which makes unlit roads hard to see. Adaptive high beams drop back to low beam for no visible reason, the beams don't adjust for hills, and the cornering lights don't work. Dealers call this normal and send owners to the manufacturer. Separate failures include condensation fogging the headlamps, a failed leveling sensor that disables adaptive lighting, and low beam error messages with reduced light output.

Unprompted opening and closing of the power tailgate is the main complaint, sometimes triggered when someone loading cargo bumps the bumper. The hatch strikes people on the head, and one injury results. Dealers say the problem can't be fixed and the feature can't be turned off without disabling keyless entry. The hatch also opens while the car is parked and unattended, leaving it unsecured. A separate report describes a glass panel between the windshield and sunroof shattering without cause.

Check engine lights appear early, sometimes within a few hundred miles, and return after dealers clear codes and update software. Other complaints describe oil leaking while the vehicle is parked, even though the oil gauge still reads normal. Hesitation, lost acceleration, and poor fuel economy are linked to fuel pump recall 23V456. In those cases owners wait weeks for recall parts while the problem continues, and the manufacturer declines to speed up the repair.

Engines shut off while driving or refuse to start, showing check engine, 48V battery, and do-not-shift warnings while an alarm keeps sounding. Restarting often works only after an hour or more. Dealers install powertrain control unit software updates. In one case they find a defective 48V hybrid battery, but the manufacturer won't let the dealer replace it, so the owner keeps driving the vehicle as is. Several owners end up stranded or needing a tow.

Sudden full stops with nothing in the path occur at 35 to 45 mph, with no warning light. One event comes while passing a parked vehicle with cruise control on, and the following driver nearly rear-ends the car. Another happens at about 12,000 miles on an access road. Driving returns to normal after a restart. The dealer tows the vehicle for diagnosis, but no repair is made.

Propulsion cuts out at highway speed. In one night crash with an injury, the digital headlights also fail. Driver aids misbehave too. Traffic sign recognition reads a speed sign meant for an exit and abruptly slows the vehicle on the highway, which raises the risk of being hit from behind. Lane keeping assist lets the vehicle drift out of its lane with no correction, and the dashboard markers stay green.