2020 Mercedes-Benz GLC Problems: 10 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 2020-2021 Mercedes-Benz GLC, two Mercedes-Benz software recalls cover rearview-image failures on GLC-Class vehicles, including the GLC Coupe. Under recall 21V354 (2020-2021 GLC), the MBUX multimedia system may not start and the display may stay black, or it may reboot about 50 seconds after startup, so the rearview camera image may not be shown or may be interrupted. Under recall 22V232 (2020 GLC; part of a 126,443-vehicle action), a rearview camera software error means that when reverse is engaged the central display may keep showing what it was already showing, or show a black screen with a message that the rearview camera is inoperative; Mercedes-Benz states the camera image itself does not freeze. Either way the image may not appear within the two seconds required by FMVSS 111. This is separate from the MBUX freeze and instrument-cluster blanking issues already on file for this nameplate. NHTSA campaign numbers: 21V354000, 22V232000.

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 2020 Mercedes-Benz GLC, the wiring harness at the electric power steering control unit on certain model year 2020 GLC vehicles (GLC300, GLC350e, AMG GLC43 and AMG GLC63; 2,533 U.S. vehicles) may have been damaged during production. A damaged harness can let moisture into the harness or the steering control unit, resulting in loss of power steering assist and an increased crash risk; a short circuit could also increase the risk of fire. NHTSA campaign number: 20V651000 (Mercedes-Benz 2020110012).

On the 2018-2020 Mercedes-Benz GLC, uS recall 20V776 / Mercedes-Benz 2021010006 covers 2,563 selected 2018–2020 AMG GLC 63 4MATIC vehicles. An incorrectly installed positive starter-cable connection can allow contact with the starter housing. Chafing can then cause a short circuit, with a potential stall or fire. Mercedes-Benz states that there is no advance warning. This campaign concerns cable installation; it is not proof that a particular vehicle's starter or other electrical components are fault-free.

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 2019-2022 Mercedes-Benz GLC, recall 24V070 covers selected 253-platform GLCs: 2019–2022 GLC300, 2020 GLC350e and 2020–2022 AMG GLC43. A production adjustment-tool deviation can leave the headlamps too high, creating glare and crash risk. Mercedes-Benz lists 15,502 vehicles and states that this failure mechanism gives the driver no warning. Model/year alone does not establish VIN eligibility.

On the 2016-2022 Mercedes-Benz GLC, x253 GLC owners report a heavy metallic clunk from the front end, most obvious over expansion joints and while turning, along with a squeak from the front suspension at low speed. The cause is the rubber bushings in the front lower spring control arm and the hydraulic (fluid-filled) thrust arm bushing, which soften and split well before the mileage owners expect — one owner documented replacement of the front suspension bushes at 38,000 miles. The fluid-filled thrust-arm bushing is the more frequent failure. Mercedes does not sell the spring-arm bushings separately, so the complete control arm assembly has to be replaced. This is a suspension-link failure and should not be confused with AIRMATIC air-suspension compressor faults, which produce a ride-height complaint rather than a clunk.

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.