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What 66 owners told NHTSA about the 2018 Mercedes-benz E-class Cabrio

These are the actual owner complaints behind this car’s reliability verdict, filed with the federal government, unedited. They’re unverified reports, not confirmed defects: read them as leads for your pre-purchase inspection, not a diagnosis.

All (66)Crash / fire / injury (7)Electrical system (13)Engine (13)Wheels (8)Steering (7)Transmission & drivetrain (6)Driver assistance (5)Body & structure (4)Brakes (4)Seat belts (4)Speed control (4)

4 of 66 complaints match · Speed control · clear filters

Feb 8, 2020Electrical systemSpeed controlBrakes

THIS NOTE REGARDS COMPLAINT NUMBER: 11301860, WHICH I PREVIOUSLY REPORTED. PLEASE REFER TO IT FOR INFORMATION. MERCEDES-BENZ TOOK THE VEHICLE TO M-B FAYETTEVILLE, NC ON 1-31-20 AND RETURNED IT ON 2-3-20. AFTER ONLY 54 MILES, THE VEHICLE IS PERFORMING EXACTLY AS IT DID WHEN I FIRST REPORTED THIS ISSUE. IN MY VIEW, THE DEFICIENCIES CAN LEAD TO A SERIOUS ACCIDENT. IT'S ELECTRONIC "SAFETY" ASSIST FACILITIES LULLS ONE INTO A DEPENDENCY AND FALSE SENSE OF SECURITY. THEN, THEY STOP WORKING WHEN THE CAR IS BEING DRIVEN ON BUSY STREETS AND HIGHWAYS.

NHTSA ODI 11307931

Jan 25, 2020Electrical systemSpeed controlBrakes

MY VEHICLE IS A 2018 MERCEDES-BENZ E63S. ON THE HIGHWAY OR IN TOWN, IT REPORTS "BRAKE-ASSIST INOPERABLE; BLIND SPOT ASSIST INOPERABLE; DISTANCE ASSIST INOPERABLE"; PLUS, THE CRUISE CONTROL HAS STOPPED WORKING. THE TROUBLE OCCURS INTERMITTENTLY. THEY ARE NOT FALSE MESSAGES. THE ITEMS REPORTED DO STOP WORKING. THAT'S EXCEEDINGLY DANGEROUS BECAUSE THE VEHICLE ESTABLISHES A FALSE SENSE OF SECURITY. BEYOND THAT, THE ENGINE IN THE CAR HAS LOST POWER NUMEROUS TIMES. THAT COULD BE CALAMITOUS IF YOU WERE PASSING AND A CAR SUDDENLY CAME AT YOU HEAD-ON. I HAVE REPORTED THIS TO MERCEDES BENZ BUT THEY HAVE FAILED TO DO ANYTHING. THEY ACT AS IF THEY SIMPLY DO NOT CARE. GO FIGURE. BUT THAT'S THE TRUTH. THAT'S OUR EXPERIENCE, AT LEAST.

NHTSA ODI 11301860

Mar 29, 2019Speed controlDriver assistance

THE VEHICLE WAS IN MOTION TRAVELING AT 35 MPH AND CONTROLLED BY ADAPTIVE CRUISE CONTROL SET AT 35 MPH. THE TIME WAS 12:40 PM ET ON 29 MARCH 2019. SEEMINGLY THE CAR WENT INTO CRASH PREVENTION MODE BY TIGHTENING THE SEAT BELT AND EXECUTING A MAXIMUM FORCE BRAKING STOP. THE TIRES SQUEALED. MY CHEST WAS SORE WHERE THE SEAT BELT RETRACTED WITH FORCE. APPROXIMATE LOCATION: SOUTHBOUND ON LANDMARK DR. NEAR ASHCROFT CT. CLEARWATER, FL 33761. LANDMARK DR. IS A RESIDENTIAL TWO LANE ROAD RUNNING NORTH-SOUTH WITH DUAL YELLOW PAINTED CENTER MARKING. ROAD IS STRAIGHT AND FLAT FOR APPROXIMATELY .2 MILE IN EACH DIRECTION. THERE WERE NO OTHER VEHICLES, PEDESTRIANS OR ANIMALS WITHIN SIGHT IN EITHER DIRECTION. WEATHER WAS SUNNY AND DRY WITH THE TEMPERATURE NEAR 82F.

NHTSA ODI 11192423

Jun 6, 2018Speed controlElectronic Stability Control (esc)

RECENTLY PURCHASED A 2018 MERCEDES-BENZ E400 4MATIC WAGON WITH PREMIUM PACKAGE 3 THAT INCLUDES ALL OF THE AVAILABLE DRIVER ASSISTANCE PROGRAMS (SEMI AUTONOMOUS STEERING, ADAPTIVE CRUISE CONTROL, LANE KEEP ASSISTANCE, BLINDSPOT DETECTION, AUTOMATIC PARKING ASSIST, CROSS TRAFFIC ALERT). ACCORDING TO MERCEDES, THE PROGRAM TITLED DRIVE PILOT WITH STEER ASSIST, IS ABLE TO KEEP THE VEHICLE IN THE LANE WHEN THERE ARE LANE MARKINGS OR EVEN FOLLOW A CAR AHEAD IF THERE ARE NO LANE MARKINGS. WELL, THIS SYSTEM IS TERRIBLE. IT CAN'T STAY CENTERED IN THE LANE, INSTEAD IT FEELS LIKE YOU'RE PLAYING A GAME OF PONG GOING BACK AND FORTH BETWEEN THE LANE MARKERS. THAT IS, WHEN IT WORKS. WHEN IT DOESN'T WORK (MOST OF THE TIME), YOU WILL BE GOING DOWN THE ROAD AND IT SUDDENLY STARTS DRIFTING OUT OF THE LANE TO FOLLOW THE CURVE OF AN OFF RAMP OR IT SUDDENLY DISABLES ITSELF BECAUSE IT CAN'T FIGURE OUT WHERE THE LANE MARKINGS ARE. THERE'S NO AUDIBLE WARNING OR BIG VISUAL CUE THE STEER ASSIST HAS ENDED, JUST A TINY LITTLE STEERING WHEEL ICON IN THE HEAD UP DISPLAY TURNS FROM GREEN TO GRAY. MERCEDES ADVERTISED THIS SYSTEM TO BE BETTER THAN OR AT LEAST ON PAR WITH TESLA'S AUTOPILOT, YET IT CAN'T READ STOP LIGHTS, CAN'T EVEN STAY IN WELL MARKED LANES AND COMBINED WITH THE ADAPTIVE CRUISE CONTROL THAT HAS NO WAY OF CHANGING HOW QUICKLY IT ACCELERATES, FEELS LIKE THE CAR IS OUT OF CONTROL. WHAT I FIND EVEN MORE DISAPPOINTING IS THAT THE MERCEDES APPARENTLY WILL NOT BE GIVEN SOFTWARE UPDATES TO IMPROVE THE SYSTEM UNLIKE TESLA WHO IS CONSTANTLY PROVIDING THEIR VEHICLES WITH OVER THE AIR UPDATES. IF MERCEDES CAN'T DO OTA UPDATES FINE, BUT THEY MUST UPDATE THESE CARS ARE THE DEALERS. I FEEL LIKE THIS SYSTEM DESPERATELY NEEDS A SOFTWARE UPDATE TO BE EVEN MARGINALLY FUNCTIONAL. DEALER HAS NO CLUE ABOUT THESE ISSUES BECAUSE OUR CAR WAS ONE OF THE ONLY ONES ORDERED WITH ALL OF THE ASSISTANCE PROGRAMS.

NHTSA ODI 11100119

Working with the data? Download all 66 complaints as CSV · fetched from NHTSA July 26, 2026

How to use these: a complaint is one owner’s report, filed voluntarily and published unverified. Patterns matter more than any single story. If several owners describe the same failure at similar mileage, put that system at the top of your pre-purchase inspection list. Back to the full 2018 Mercedes-benz E-class Cabrio verdict →