2023 Mercedes-Benz GLC Problems: 11 Known Issues

On the 2017-2024 Mercedes-Benz GLC, gLC owners report the driver-assistance suite reacting to obstacles that are not there. The "checking surroundings" screen pops up several times a week with sections of the car outlined in red and nothing nearby, and — more seriously — Active Brake Assist has applied the brakes with no vehicle or object ahead. Owners on the Mercedes forums describe the system cutting the accelerator because it believes an obstacle is present, and multiple owners across the GLC and its C-Class platform siblings report the same event, encouraging one another to file NHTSA complaints. Mercedes' 2019 recall 19V540 fixed a radar sensor control unit software error on several models, including some 2020 GLCs, but that error stopped Active Brake Assist from braking rather than triggering it; the general failure mode here is the radar or camera misreading a roadside object as a collision threat. An unexpected full-force brake application in traffic is a rear-end collision risk.

On the 2023-2024 Mercedes-Benz GLC, on the second-generation X254 GLC the micro-switch inside the driver's door lock tells the car whether the door is open. Its housing material is more permeable to moisture than intended, so the switch corrodes and stops reporting a door-open event. Because the Auto-Park function and the automatic engagement of the electronic parking brake are triggered by that door-open signal, the car can be left with no parking brake applied when the driver steps out — and roll away. Mercedes recalled 310,667 vehicles in July 2026 over this, including 2023-2024 GLC models. The root cause is the door lock, not the parking brake itself, which is why owners who complained of parking-brake behaviour were often told nothing was wrong.

On the 2023-2025 Mercedes-Benz GLC, recall 25V379 covers certain panoramic-roof X254 GLC SUVs. Rear roof-lining damping may be too stiff for the specified FMVSS 201u unbelted head-impact test, creating a risk of excessive head-injury criteria in the defined no-airbag-deployment scenario. The filing lists 92,739 vehicles: GLC 300/300 4MATIC for 2023–2025, AMG GLC 43 for 2024–2025, and GLC 350e/AMG GLC 63 S E for 2025. Confirm the individual VIN; the overall year range does not apply to every trim.

On the 2023-2025 Mercedes-Benz GLC, owners of the second-generation X254 GLC report the 12V system going flat after only a few days parked, with a "12V Battery Low" message and, in a number of cases, a no-start and a tow. This is separate from the 48V mild-hybrid starter-generator failure: here the 48V system is healthy and it is the conventional 12V board net being drained. Mercedes technicians and owners on the GLC forums traced the parasitic draw to the door control modules failing to go to sleep, and service centres have addressed it by reflashing all control units including the Door Control Module. Some owners were told by dealers to charge the battery every three days and drive at least 40 minutes daily — a workaround, not a fix — and several report being towed more than once before the module software was updated.

On the 2023-2025 Mercedes-Benz GLC M254 2.0L turbo I4 (48V ISG), gLC 300 models of the second-generation (X254, 2023-on) GLC with the M254 engine use a 48-volt mild-hybrid system with an Integrated Starter-Generator (ISG) mounted between the engine and transmission, fed by a small lithium-ion battery. The ISG, its 48V battery, or a loose/overheating 48V ground connection can fail, triggering a '48V On-Board Electrical System Malfunction' warning. Failures often cause a no-start condition that cannot be jump-started, stalling while driving, or in severe cases overheated connections posing a fire risk. Because the ISG sits between engine and gearbox, repair is labor-intensive and expensive.

On the 2020-2023 Mercedes-Benz GLC M264 2.0L turbocharged inline-4, certain M264-equipped GLC 300 vehicles can develop irregular wear of the exhaust valve guide or seat, leading to misfire and a check-engine light. Mercedes-Benz USA's January 2026 warranty notice lists model-year 2020–2023 GLC 300, GLC 300 4MATIC and GLC 300 4MATIC Coupe. A misfire does not by itself prove this condition; diagnosis must distinguish ignition, injection and mechanical faults.

On the 2016-2023 Mercedes-Benz GLC, on the M274/M264 2.0L turbo engines used in the GLC, the intake camshaft adjuster relies on an internal locking pin that wears over time. Without oil pressure at cold start, the adjuster fails to lock in its default position, producing a distinct metallic rattle for 2-4 seconds on a cold start. Oil leaking around the camshaft adjuster solenoid can also seep into the wiring harness and trigger timing faults. Left unrepaired it risks valve-timing errors and further engine wear.

On the 2021-2023 Mercedes-Benz GLC M264 2.0L turbo I4, recall 23V445 directly covers 43,257 model-year 2021-2023 GLC 300 vehicles with fuel-pump impellers that may not meet material specifications. An affected impeller may deform, contact the pump housing and create mechanical resistance; in some instances the fuel pump can shut down and the vehicle can lose propulsion, increasing crash risk. A warning message or rough running may occur before shutdown. The 43,257-vehicle population is not an owner-report count.

On the 2023-2026 Mercedes-Benz GLC, recall 25V533 directly covers model-year 2023-2026 GLC 300 and GLC 300 4MATIC vehicles whose steering-coupling bolt may not have been torqued to production specifications. The connection can loosen over time, potentially causing loss of steering control and increasing crash risk. The report lists 1,686 GLC 300 4MATIC and 677 GLC 300 vehicles; those are recall populations, not owner-report totals.

On the 2016-2024 Mercedes-Benz GLC, gLC headlamp assemblies collect water inside the lens. Mercedes recalled a narrow build window — 129 units of 2021 GLC 300, GLC 300 4MATIC, AMG GLC 43 and AMG GLC 63/63 S built May-June 2021 — because the sealing plugs in the headlamp connector housing were not properly installed, letting water reach the electrical connection and causing headlight failure. Beyond that recall population, owners across the X253 and X254 generations report heavy condensation inside LED headlights from compromised gaskets or blocked vent tubes, including new X254 cars fogging on one side, being replaced, and then fogging on the other. Dealers have handled non-recall cases by inserting silica gel desiccant bags under warranty, which owners describe as a temporary measure rather than a repair.

On the 2016-2023 Mercedes-Benz GLC, on X253 GLCs with the automatically opening tailgate, a left and a right gas-charged support strut work together with the electric tailgate drive. When the gas charge leaks out of the passive strut, the tailgate no longer has enough force to stay up: owners describe the boot opening normally and then immediately closing again faster than normal, or drifting down onto the person loading the car. Because the electric drive is still working, the symptom is easily misread as a liftgate motor or module fault and owners are quoted for the expensive drive unit when the failed part is the inexpensive gas strut. A tailgate that comes down under its own weight is a genuine head and hand injury risk.