Mercedes-Benz EQS 450+ Reliability

The MBUX Hyperscreen (56-inch curved display) occasionally becomes laggy, freezes completely, or restarts on its own. Owners report the system only refreshes every half second instead of smoothly, especially when using navigation or Apple CarPlay. Most issues stem from software bugs or out-of-date software. Mercedes dealers can update all software in approximately 3.5-23 hours (varies by update scope), and most owners report significant improvement afterward. A Mercedes recall affected 8,530 EQS and S-Class vehicles built between July 2020 and January 2022 for MBUX issues. If the problem persists after updates, hardware replacement may be needed under warranty. The car has over 100 control units that must communicate with the central unit, and timing issues can raise errors - often a system reset solves the problem.

This is the most serious and widespread issue. 72% of complaints to NHTSA about the 2022 EQS involve forward collision avoidance and phantom braking. Owners report sudden, violent emergency braking at 45+ mph with no obstruction, and abrupt braking while reversing in parking areas. One owner experienced the emergency brakes engaging at 55 mph, deploying airbags and bringing the car to a halt for no reason. Mercedes USA issued a position statement saying this falls under "operating as designed" and refuses warranty coverage for damage caused. Some owners have switched the emergency braking setting from "normal" to "late" or turned it off completely (though it re-enables at next startup). Despite 13 recalls for the 2022 EQS, none address this phantom braking issue. Several owners have pursued lemon law cases. This is not merely an annoyance - it's a genuine safety concern that can cause rear-end collisions.

Multiple owners report significant range reduction after software updates at Mercedes dealers. One 2022 EQS 450+ owner saw range at 80% charge drop from 340-350 miles to only 275-280 miles over 30 days. Another reported full battery capacity dropped from 730 km to 630 km after a dealer update (100 km loss). Efficiency also suffers - one owner's average dropped from 3.3 mi/kWh to 2.1 mi/kWh with no explanation from the dealer. In extreme cases, owners lost 50% of battery capacity after updates, requiring months to diagnose. Mercedes has issued a recall for 14,912 EVs (2023-2025 EQS/EQE models) for battery management system software that doesn't meet production specifications. The fix requires a dealer visit (cannot be done OTA). Some owners have experienced cars locking them out after failed OTA updates. Mercedes "really has not figured out the process yet and software upgrades often cause more problems," according to dealer feedback.

The EQS uses Mercedes AIRMATIC air suspension, which has known reliability issues as it ages. Most common problem is leaking air struts - rubber seals become brittle, cracked, or punctured, causing air leaks. You'll hear hissing sounds and see the vehicle sagging (usually rear first). Replacing a single air spring costs €2,500+. The compressor can also fail, especially if moisture enters and causes corrosion - this moisture can spread to other components like air springs, causing cascading failures. Other failure points include damping valves (€700-1,500) and height sensors. One EQS forum user reported loss of air pressure issues requiring dealer attention. With proper maintenance, AIRMATIC components typically last 6-10 years. Repair costs vary: single component repair starts around €500, but complete suspension work (front and rear) can reach €4,000-5,000. Some owners eventually convert to coil springs to eliminate ongoing air suspension problems, though this removes the adaptive ride quality.

Like many EVs with extensive electronics, the EQS draws power from the 12V auxiliary battery even when parked. The car has three 12V batteries: a 1.2 Ah auxiliary/support battery, a 26 Ah buffer battery in the rear, and a 60 Ah main 12V battery. If the vehicle sits unused for 7-10 days without being plugged in, the 12V system can drain completely, leaving you unable to unlock or start the car. Replacement of the 12V battery costs from €305 for parts and labor. The auxiliary battery specifically (1.3 Ah) can be replaced with aftermarket options. Most auxiliary batteries last 5-7 years. When replacing, the new battery must be programmed into the vehicle's SAM module using a scan tool. To avoid this issue, keep the car plugged in when not in use, or use the Mercedes Me app to monitor 12V battery status remotely. Unlike the high-voltage battery drain issue (which has been recalled), the 12V drain is considered normal for a car with this many electronic systems.

The EQS features Mercedes Digital Light headlights with 1.3 million micro-mirrors per headlight, creating an incredibly precise and adaptive beam pattern. When these fail (rare, but it happens), replacement cost is extraordinarily high. Standard Mercedes LED headlights already cost €1,500+ per unit, and the Digital Light system with its micro-mirror technology is significantly more expensive - likely €2,500-3,500 per headlight. The unit requires coding to the vehicle after replacement, adding to complexity. Forum users report occasional headlight failures requiring dealer attention. Mercedes is working on making future headlights repairable (using screws instead of glue) so lenses can be replaced individually rather than the entire assembly, but current EQS models still use the older, non-serviceable design. Labor costs at Mercedes dealers run €150-250/hour. One positive note: if damage occurs within warranty period, it should be covered. Outside warranty, this is one of the most expensive single components to replace on the vehicle.

Some EQS owners report charging issues where the car stops accepting a charge or shows "charging start error" at various charging stations (Electrify America, EVgo, ChargePoint). AC charging (Level 2) issues include the car working initially then showing error messages, or charging rate dropping dramatically (from 8 kW to 3.5 kW with no setting changes). DC fast charging problems include inability to initiate charging despite trying all methods (app, RFID card, credit card). In documented cases, the AC/DC converter required replacement after the high-voltage system was deactivated. The part itself plus labor costs approximately €800-1,500 for AC charger components, potentially more for integrated systems. Some owners have had to try 10+ charging stations before finding one that works, suggesting vehicle-side hardware issues rather than network problems. DC fast charging may also be slow or unavailable if the battery is too hot or too cold, which is normal thermal management behavior. Mercedes technical support should diagnose charging issues under warranty. Peak DC charging rate is 200 kW, allowing 10-80% charge in about 31 minutes when working correctly.

Several EQS owners report rattling noises from the panoramic sunroof, particularly when driving on uneven roads. The issue stems from loose mounting screws, misaligned seals, or the dome light assembly rattling against the headliner. Dealers can typically fix this by adjusting the Torx screws that hold the sunroof panel (tightening them for a better seal), or by repositioning the sunroof track mechanism. Some owners report the rattle returns after a few weeks or months, requiring repeated dealer visits. DIY fixes include sliding foam strips between the roof cover and headliner, or using sticky-backed felt tape on metal contact points. For EQS-specific issues, dealers may need to perform a "teach-in run" for the automatic reversing function after adjustments. The work typically takes 20 minutes to a few hours depending on severity. Under warranty, this should be covered. Out of warranty, expect €100-300 for dealer diagnosis and adjustment. This is more of an annoyance than a serious failure, but it detracts from the premium experience you expect in a €100,000+ vehicle.

The EQS uses a complex thermal management system with multiple cooling loops for the battery, inverter, motor, and cabin. Common issues include expansion valve failures (part Y140/1, which modulates refrigerant flow) - older part number A 297 830 79 03 should be updated to A 297 830 89 03. The valve becomes mechanically stuck over time, causing battery overheating warnings and power reduction. Coolant switchover valve (A0005061400) can also stick, generating cooling system alerts. Some EQ models in China (EQC, EQA, EQB) had a widespread coolant leak recall due to flawed motors - while not officially confirmed for EQS, some European owners report similar coolant leaks. Symptoms include coolant warning lights, sweet smell (coolant leak), steam from under the hood, and in severe cases, repeated electric motor replacements. The EQS cooling system also includes a heat pump that can fail. Repair costs vary: expansion valve replacement €500-800, switchover valve €400-600, coolant pump €600-1,000. If electric motor coolant seals fail, motor replacement can reach €2,000-4,000. Most issues appear under warranty and should be covered.