2020 Mercedes-Benz GLC 300 problems & reliability
67 owner complaints filed with NHTSA for the 2020 Mercedes-Benz GLC 300, alongside 16 safety recall campaigns. Last verified Aug 7, 2026. Complaints are unverified reports submitted by owners to the federal Office of Defects Investigation.
Each complaint is counted once (by NHTSA case number), even when it names several vehicles.
2 complaints report injuries (4 injured).
Most reported problems
| Component | Complaints | Share |
|---|---|---|
| Engine → | 20 | 30% |
| Unknown OR Other | 15 | 22% |
| Back Over Prevention | 7 | 10% |
| Electrical System | 5 | 7% |
| Exterior Lighting | 5 | 7% |
| Forward Collision Avoidance | 5 | 7% |
| Steering | 5 | 7% |
| Fuel/propulsion System | 4 | 6% |
| Power Train | 4 | 6% |
| Service Brakes | 3 | 4% |
Component groups as classified by NHTSA. A complaint can name more than one component, so shares may sum to more than 100%.
Common symptoms owners describe
Keyword analysis of complaint narratives; one complaint can describe several symptoms.
Complaints by incident year
What owners report
“My 2020 Mercedes-Benz GLC 300 triggered check engine light with code P06DA (engine oil pressure control) at 40,000 miles. The failed component is an oil pressure control sensor/solenoid worth approximately $200. However, due to Mercedes-Benz's engine design (M264 engine), the entire engine must be removed from the…”
Engine · filed Jun 25, 2026
“I have had my car for almost two years. This problem has been on-going the whole time. It happens intermittently, I never know. I will be driving it and usually when I am making a turn or pulling onto a main road, you press the gas to go and the car hesitates and makes a loud brooooooooom sound like it is trying to go…”
Fuel/propulsion System · filed May 13, 2026
“There was a recall on headlight leaking and this happened to my left headlight no damage but leaking and this caused headlight to not work”
Exterior Lighting · filed Feb 19, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Technical service bulletins
215 manufacturer communications (TSBs, service campaigns, warranty extensions) are on file with NHTSA for the 2020 Mercedes-Benz GLC 300. The 10 most recent:
This NCU replaces the prior NCU issued on May 15, 2025, and contains additional MY 2023 and MY 2024 vehicles which are highlighted below. In our continuing efforts to ensure the proper performance of Mercedes-Benz…
EW - DMTL · Warranty Program/Extension · issued Jul 31, 2026
Mercedes-Benz AG (“MBAG”), the manufacturer of Mercedes-Benz, has determined that on certain MY 2019-2021 C-Class, G-Class, GLC, GT, S-Class (205, 463, 253, 190 & 222 platforms) vehicles, the engine control unit…
Emissions - 2024100016 · Emissions · issued Jul 24, 2026
Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end). The noise is heard once in each instance when changing direction of travel. Note: Sound file in attachment Cause…
LI35.30-P-058566 · Service Bulletin/Repair Instructions · issued Jul 14, 2026
Complaint Creaking noise, in irregular sequence when driving slowly in combination with slight steering movements and/or Creaking/crackling noises from the area of the wheel bearing on the front axle when cornering/…
LI33.20-P-078406 · Service Bulletin/Repair Instructions · issued Jul 8, 2026
Complaint Creaking noise, in irregular sequence when driving slowly in combination with slight steering movements and/or Creaking/crackling noises from the area of the wheel bearing on the front axle when cornering/…
LI33.20-P-078406 · Service Bulletin/Repair Instructions · issued Jul 7, 2026
Dear Mercedes-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed, and any existing stock must be returned to your facing PDC. The deadline for all dealer returns is no later than…
PSL-NCU Return Parts 6/19 · Other · issued Jun 19, 2026
Complaint Service code B1 displayed in the customer menu does not match the workshop code displayed in the workshop menu, e.g., 505 or 550A, which includes a service A. Cause The root cause is currently being…
LI00.20-P-080703 · Service Bulletin/Repair Instructions · issued Jun 12, 2026
Complaint After successful commissioning of the HERMES control unit (N112/9) with XENTRY Diagnosis DVD 03/2026, the message "SOS - service not activated" appears on the instrument cluster. In addition, the following two…
LI82.85-P-080507 · Service Bulletin/Repair Instructions · issued May 26, 2026
Complaint The customer requests deactivation of the N112/9 HERMES communication module Note: Deactivation of the HERMES control unit (N112/9) is not supported for gray-market vehicles. Cause Before deactivating the…
LI82.85-P-080559 · Service Bulletin/Repair Instructions · issued May 26, 2026
Dear Mercedes-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed, and any existing stock must be returned to your facing PDC. The deadline for all dealer returns is no later than…
PSL-NCU Return Parts 5/22 · Other · issued May 22, 2026
TSBs are repair guidance manufacturers send to dealers — they are not recalls and repairs are not automatically free. Full documents are available on NHTSA’s site.
Safety recalls
The 2020 Mercedes-Benz GLC 300 has 16 NHTSA recall campaigns — recall repairs are free at franchised dealers regardless of the vehicle’s age.
Check whether your specific vehicle is affected
Recall campaigns often cover only certain VIN ranges. Enter your VIN on the official NHTSA site to confirm whether your vehicle is included and whether the repair is still open.
Check VIN on NHTSA →Buying a used 2020 Mercedes-Benz GLC 300?
- · Decode the seller’s VIN with our free VIN decoder to confirm the exact year, engine and trim.
- · Check for unrepaired recalls by VIN on NHTSA’s official lookup — recall repairs are free.