Sep 29, 2025Electrical systemEngine
My 2015 Mercedes-Benz GL63 AMG has suffered two separate ECU failures caused by oil migrating through the engine wiring harness. The first failure occurred at ~42,600 miles in 2020, and the second at ~59,000 miles in 2023. Both times, the vehicle developed misfires, check-engine warnings, and drivability issues that could have led to stalling at highway speeds. On both occasions, the vehicle has been completely disabled. Repairs required replacement of the wiring harness, ECU, sensors, and fuse box, costing over $5,600. This is a hidden, recurring defect that poses a safety risk and financial burden. The vehicle does not feel safe or reliable to drive, and dealer support and guidance is non-existent. I have been afraid to drive to the point that it has only accumulated 3,000 additional miles in the last two years.
NHTSA ODI 11690238
Mar 17, 2022Electrical systemBody & structureEngine
The rubber sealing around the lift gate failed on the vehicle and water seeped inside the vehicle and entire bottom of the vehicle underneath the floor board thereby damaging the electronic components, engine wire harness and headliner thereby rendering the vehicle was beyond repair. This issue led to mold to grow on the roof liner inside and on the seats which caused breathing issues for me and my family. This put our safety at risk! After talking the vehicle to authorized Mercedes Benz dealer in San Jose CA I was told that this is a known defect with the vehicle about which Mercedes Benz Inc is well aware for years and has not fixed it or recalled vehicles having this safety issue. I had purchased this vehicle from Mercedes Benz of Pleasanton on 6/10/2015 as Certified Pre Owned (CPO) but I was not informed that this safety issue existed. I was informed by Mercedes Benz of San Jose that the vehicle could not be repaired as mold would pose a health hazard for the occupants and the vehicle was deemed to be beyond repair and totaled. I had also purchased extended warranty at the time of purchase in 2015 but the dealership did not honor it for repairs.
NHTSA ODI 11457171
Sep 18, 2020Electrical systemEngine
THE VEHICLE MISFIRED WHILE DRIVING ON CITY STREETS AND PRESENTED A CODE FOR FAULTY IGNITION COILS. UPON INSPECTION, MERCEDES-BENZ SERVICE CENTER FOUND OIL IN THE ENGINE WIRING HARNESS RENDERING THE CAR UNDRIVEABLE.
NHTSA ODI 11359766
Sep 18, 2018Electrical systemEngine
TL* THE CONTACT OWNS A 2015 MERCEDES-BENZ GL450. WHILE DRIVING 40 MPH, THE VEHICLE STALLED AND THE PRE-SAFETY FUNCTION LIMITED WARNING INDICATOR ILLUMINATED. THE VEHICLE WAS PUSHED OVER TO THE SIDE OF THE ROAD BY THE CONTACT AND PASSENGER. THE CONTACT ATTEMPTED TO RESTART THE VEHICLE, BUT IT FAILED TO START. THE VEHICLE WAS TOWED TO MERCEDES-BENZ OF ARCADIA (101 N SANTA ANITA AVE, ARCADIA, CA 91006, (626) 701-8904) WHERE IT WAS DIAGNOSED THAT A LOOSE SCREW WAS NOT FASTENED BY THE MANUFACTURER AND AN UNKNOWN WIRE WAS DETACHED, WHICH CAUSED THE VEHICLE TO STALL. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS MADE AWARE OF THE FAILURE AND DID NOT ASSIST. THE APPROXIMATE FAILURE MILEAGE WAS 25,000.
NHTSA ODI 11130224