2020 Mercedes-Benz GLS 450 problems & reliability
35 owner complaints filed with NHTSA for the 2020 Mercedes-Benz GLS 450, alongside 20 safety recall campaigns. Last verified Aug 8, 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 components.
1 complaint report injuries (2 injured).
Most reported problems
| Component | Complaints | Share |
|---|---|---|
| Electrical System → | 18 | 51% |
| Engine | 9 | 26% |
| Forward Collision Avoidance | 7 | 20% |
| Fuel/propulsion System | 6 | 17% |
| Power Train | 4 | 11% |
| Unknown / Other | 4 | 11% |
| Air Bags | 2 | 6% |
| Back Over Prevention | 2 | 6% |
| Service Brakes | 2 | 6% |
| Structure | 2 | 6% |
Component groups as classified by NHTSA. A complaint can name more than one component, so shares may sum to more than 100%.
All 15 reported components →Common symptoms owners describe
Keyword analysis of complaint narratives; one complaint can describe several symptoms.
Complaints by incident year
What owners report
“AMENDMENT TO ACTIVE CASE 11723015. CRITICAL AIRBAG & SAFETY DEFECTS. This files a safety defect amendment to open case 11723015. Diagnostic scans confirm central data bus network collapse on VIN [XXX] has migrated into safety-critical occupant restraint and visibility modules, violating 49 U.S.C. § 30118. I. AIRBAG &…”
Air Bags · filed Jun 3, 2026
“The contact owns a 2020 Mercedes Benz GLS. The contact stated that while driving on the highway, the rear door window trim bars on the passenger side detached from the window. The vehicle was taken to the dealer where they diagnosed as a rear door window trim detachment however the vehicle was not repaired. The…”
Structure · filed May 15, 2026
“Window trim on the passenger rear window fell off while driving- it put others at risk by flying off the vehicle on the interstate- Mercedes Benz of Omaha quoted replacement of the window trim parts- no warning messages on dash”
Structure · filed May 15, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Technical service bulletins
247 manufacturer communications (TSBs, service campaigns, warranty extensions) are on file with NHTSA for the 2020 Mercedes-Benz GLS 450. 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
Complaint CEL light on with no drivability concerns. Cause Signal timing error. Remedy 167, 465: SW has been released. Update the FSAM to the latest SW version. 290, 118, 243, 247: Software is still in development. This…
LI54.21-P-080326 · Service Bulletin/Repair Instructions · issued Jul 24, 2026
Complaint Noise from front end attributable to steering gear. Cause During diagnostics of a front end noise, workshop is under the impression the noise is coming from the steering gear. Remedy Workshop diagnostics point…
LI46.00-P-079786 · Service Bulletin/Repair Instructions · issued Jul 22, 2026
Complaint Hand detection system – malfunction / vehicles with code 266 Fault message in instrument cluster: "Active Emergency Stop Assist not available" "Active Lane Keeping Assist not available" "Active steering assist…
LI46.10-P-078012 · Service Bulletin/Repair Instructions · issued Jul 17, 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 Traffic sign symbol for "Traffic Sign Assist" is blinking in instrument cluster without obvious cause usually with one of the following scenarios: • Flashing without a speed limit ("- -"). • Flashing when…
LI54.71-P-079104 · Service Bulletin/Repair Instructions · issued Jul 9, 2026
Complaint Radio station cover art does not refresh when switching stations. The UI continues to show the old station’s artwork instead of updating to the new one. Cause When a new station change request is triggered, a…
LI82.60-P-080383 · Service Bulletin/Repair Instructions · issued Jul 8, 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 7/3 · Other · issued Jul 3, 2026
Complaint Throbbing/humming sound around 60mph. Howling in overdrive mode around 5th gear. Models 167.1/3 and 167.9 as of 03/2022 (except 167.987) occurs between 40-50mph Model 167.987 as of 03/2022 occurs between…
LI35.25-P-077385 · Service Bulletin/Repair Instructions · issued Jul 2, 2026
Complaint 1. Maybach Night Series image not being displayed in Head Unit, Instrument Cluster, CCR and RSU displays 2. Car line picture mismatch between Instrument Cluster and Head Unit display 3. Menu icons missing in…
LI82.60-P-080702 · Service Bulletin/Repair Instructions · issued Jun 15, 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 GLS 450 has 20 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 GLS 450?
- · 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.