2021 Mercedes-Benz S-Class problems
Light NHTSA footprint — 33 owner complaints. Either a clean record or thin data; we'll show what's there.
The 2021 Mercedes-Benz S-Class has 33 NHTSA owner complaints on file (U.S. federal records, as of July 2026). The most-reported system is electrical at 8 complaints, typically surfacing around 10,500 miles (~$850 to repair). Source: NHTSA Office of Defects Investigation.
| Model year | Owner complaints | Recalls |
|---|---|---|
| 2018 S-Class | 29 | 0 |
| 2019 S-Class | 16 | 0 |
| 2020 S-Class | 7 | 0 |
| 2021 S-Class (this page) | 33 | 0 |
| 2022 S-Class | 46 | 0 |
| 2023 S-Class | 12 | 0 |
| 2024 S-Class | 6 | 0 |
Solid reliability overall. Common issues are concentrated in a few systems.
Buyable on the data — keep up the usual maintenance and inspect normally.
- No systemic severe-failure pattern in the complaint record
- Reliability score 8.4/10 — above the segment average
Our read of the federal NHTSA complaint and recall record for this exact year and model — not a substitute for a pre-purchase inspection. How we score.
Buying a used 2021 Mercedes-Benz S-Class? Check these first
Here's what this model is known to do — so you can inspect for it, price it in, or make the seller fix it before you sign.
What to inspect on this specific car
- electrical — 8 owner reports · tends to show around 10,500 mi · ~$850 to fix
- engine — 6 owner reports · tends to show around 29,350 mi · ~$3,100 to fix
- wheels — 6 owner reports · ~$400 to fix
⚠ The one to take seriously: electrical is flagged severe on this model , showing up around 10,500 mi. Inspect it closely on a test drive.
Recalls to confirm are done
Run the VIN from the listing — no active recalls on this model right now, but confirm none were opened after this car was built.
Verdict for buyers: 8.4/10 model. The priciest documented failure is engine (~$3,100) — get the seller's service records for it or inspect closely. Otherwise an average-risk used buy at a fair price.
We tell you what this model is known for and what to inspect — a vehicle-history report tells you what this exact car has been through. Smart buyers get both.
See the full pre-purchase inspection checklist →Ask anything about your 2021 Mercedes-Benz S-Class
A noise, a warning light, a repair quote, "should I buy this?" — get an answer grounded in this vehicle's actual NHTSA record, not generic advice.
Answers use this vehicle's NHTSA complaint & recall record — owner-reported and unverified, not a diagnosis. Verify anything safety-critical with a mechanic.
Top trouble spots 3 categories with 3+ complaints
What owners are saying recent NHTSA-filed complaints · verbatim
The contact owns a 2021 Mercedes-Benz S580. The contact received notification of NHTSA Campaign Number: 24V704000 (ENGINE AND ENGINE COOLING); however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of…
The contact owns a 2021 Mercedes-Benz S580. The contact stated while driving approximately 5 MPH, the brakes failed to function as needed while the brake pedal was being depressed. The failure resulted in a crash. There were no injuries sustained. The contact stated that the…
The contact owns a 2021 Mercedes-Benz S580. The contact received a notification for NHTSA Campaign Number: 21V843000 (Engine and Engine Cooling) however, the part to do the recall repair was unavailable. The dealer had been notified about the recall; however, the contact was…
The contact owns a 2021 Mercedes-Benz. The contact stated while driving at 10 MPH, the vehicle stalls until the contact engages the vehicle in sport mode. The vehicle was not taken to an independent mechanic or dealer for diagnosis or repairs. The manufacturer was not notified…
Estimate your repair exposure
Drag to your current mileage. Numbers are derived from this vehicle's complaint history.
Common questions
Is the 2021 Mercedes-Benz S-Class reliable?
Mostly yes. With a reliability score of 8.4 out of 10 based on 33 owner complaints filed with NHTSA, the 2021 Mercedes-Benz S-Class is generally a sound vehicle. The areas to watch are listed in the top problem section above — most are budget items, not deal-breakers.
Should you avoid the 2021 Mercedes-Benz S-Class?
On the NHTSA data, the 2021 Mercedes-Benz S-Class does not need avoiding. Buyable on the data — keep up the usual maintenance and inspect normally. The record behind that call: No systemic severe-failure pattern in the complaint record; Reliability score 8.4/10 — above the segment average. This is our read of the federal complaint and recall data — not a substitute for a pre-purchase inspection.
What should I check before buying a used 2021 Mercedes-Benz S-Class?
Inspect the electrical first — it's the most-reported issue on this model, with 8 owner complaints filed. Typical failure occurs around 10,500 miles. Average repair cost runs about $850 at an independent shop. Also confirm any open recalls have been completed by running the VIN, and ask for service records covering the problem areas listed above.
Is the 2021 Mercedes-Benz S-Class a good used car to buy?
It scores 8.4 out of 10 on our NHTSA-based read of 33 owner complaints. The main thing to watch is electrical. Typical failure occurs around 10,500 miles. Priced fairly and clean on inspection, it's a reasonable used buy. Our data covers what this model is known for — pair it with a vehicle-history report on the VIN to see what that specific car has been through.
What's the most common problem on the 2021 Mercedes-Benz S-Class?
Based on NHTSA records, the most-reported issue is electrical, with 8 complaints filed. Typical failure occurs around 10,500 miles. Average repair cost runs about $850 at an independent shop.
What's the most expensive thing that goes wrong?
The electrical is one of the costlier repair items. Average repair cost runs about $850 at an independent shop. Typical failure occurs around 10,500 miles. Catching early warning signs can sometimes extend life by 20–30,000 miles.
How do I check if my Mercedes-Benz S-Class has open recalls?
Paste your VIN into the decoder at the top of this page. We pull live from NHTSA, so you'll see exactly which campaigns apply to your vehicle and whether the dealer has logged the fix. Recall repairs are always free regardless of mileage or warranty status.
Is an extended warranty worth it on a 2021 Mercedes-Benz S-Class?
Math is straightforward: a quality service contract runs $1,800–3,500 over 3 years. With 33 complaints on file and the costliest repair averaging $850, one major failure more than pays for it. The catch is reading the contract — many providers exclude wear items and require pre-authorization, so cheaper plans are not always better value.