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 Sep 22, 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 &…”
Electrical System · 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”
Unknown / Other · filed May 15, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Technical service bulletins
256 manufacturer communications (TSBs, service campaigns, warranty extensions) are on file with NHTSA for the 2020 Mercedes-Benz GLS 450. The 10 most recent:
Complaint During part of the steering movement, it feels heavier or more difficult to steer in the same spot every time. OR Rattling, humming, dry sliding/gravel noise from the electric steering system when steering…
LI46.35-P-067339 · Service Bulletin/Repair Instructions · issued Aug 28, 2026
Complaint Noise from front end thought to be from steering gear. Cause During diagnostics of a front end noise, workshop is under the impression the noise is coming from the steering gear. Remedy If the root cause of…
LI46.00-P-079786 · Service Bulletin/Repair Instructions · issued Aug 28, 2026
Complaint Tailgate opens unintentionally. Cause Accidental or unnoticed activation of the button to open the tailgate on the vehicle key. EXAMPLE: when stored in trouser pocket, handbag etc. Remedy As of the 6th…
LI72.20-P-075746 · Service Bulletin/Repair Instructions · issued Aug 24, 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 Aug 22, 2026
Dear Mercedes-Benz Owner: In our continuing efforts to ensure the proper performance of Mercedes-Benz products and to enhance the satisfaction of our customers, Mercedes-Benz USA is extending the warranty coverage for…
CL - Tank Leak Detection · Warranty Program/Extension · issued Aug 15, 2026
Complaint 1. General Diagnostic Tips 2. One or More PARK Sensor Activations 3. Red Ring Around Vehicle 4. "Active Parking and Parking Assist Inoperative" on Instrument Cluster 5. Cameras 6. Other Park Topics. Cause…
LI54.65-P-080132 · Service Bulletin/Repair Instructions · issued Aug 12, 2026
Complaint Clanking noise from the area of the speakers in the doors. Cause Under analysis. Remedy To narrow down the cause, first of all remove the door trim. • If the noise continues to occur even with the door trim…
LI82.62-P-078631 · Service Bulletin/Repair Instructions · issued Aug 6, 2026
Complaint This document is intended as a pre-case diagnostic reference for transmission related concerns. It will also ensure that if a case is necessary, all supporting documentation is available. This should not be…
LI27.00-P-075630 · Service Bulletin/Repair Instructions · issued Aug 5, 2026
Complaint Mercedes-Benz USA is currently experiencing limited availability of transmission fluid specification ATF 236.17 due to a global supply constraint. 236.17 ATF 1L and 5L (PNs: A002989060312 and A002989060313)…
LI27.00-P-080840 · Service Bulletin/Repair Instructions · issued Aug 4, 2026
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
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.