MERCEDES-BENZ Complaints

Fuel smell in vehicle. Upon investigation found fuel pump flange cracked and leaking fuel. Leaking fuel is a fire hazard. No warning lamps illuminated.

My 2025 Mercedes-Benz GLC 350e displayed a “48V battery malfunction” warning on or about July 1, 2026, while the vehicle was less than one year old. The vehicle was taken to an authorized Mercedes-Benz dealership and remained there until approximately July 20. Mercedes-Benz USA became involved, and the dealership ultimately stated that the malfunction had been corrected through a software update. The 48V battery was not replaced. I have not received documentation clearly identifying the specific software update, campaign, operation number, underlying failure mechanism, or pre- and post-repair diagnostic results establishing that the reported malfunction was caused and resolved by software. I am therefore unable to determine whether the battery or another component of the 48V system was defective, or whether the warning was merely cleared. In late August, I also heard a new and pronounced whirring sound near the left-front area of the vehicle after charging. A different authorized dealership charged the high-voltage battery to 100%, attempted to reproduce the sound, and found no charging-system fault codes or abnormal noise. It characterized the sound as normal post-charge cooling operation and performed no repair. I am submitting this complaint because of the original 48V malfunction, the lack of documentation identifying exactly what failed and what software remedy was performed, and the possible relevance to a previously closed NHTSA investigation involving Mercedes-Benz battery-related concerns. Please associate this complaint with any applicable closed investigation and evaluate whether this incident constitutes additional relevant field evidence.

The contact owns a 2019 Mercedes-Benz GLS450 4Matic. The contact stated that vehicle was taken to the dealer for routine service, and it was discovered that the U-joint on front driveshaft was fractured and needed to be replaced. The contact associated the failure with NHTSA Campaign Number: 26V216000 (Power Train); however, the VIN was not included in the recall. The failure mileage was approximately 56,000.

The vehicle was involved in a collision on January 26, 2023. I am not claiming that the computer malfunction caused that collision. After the collision, while I continued operating the vehicle, problems developed with the vehicle’s computer, electronic control system, and instrument cluster. The instrument display could become dark or unavailable, and a CHECK ENGINE warning was present. This prevented reliable access to important information such as vehicle speed, warnings, and operating status. I brought the vehicle to a repair facility expecting a complete inspection and repair. An insurance inspector was expected to inspect and document the vehicle before repairs, but the inspector did not arrive after I waited for the entire day. I was told that the inspector would not be available the following days and would come only when available. Relying on the instructions I received, I left the vehicle at the repair facility. I authorized a complete repair, not an incomplete or partial repair. Nevertheless, the vehicle was only partially repaired, and the computer and instrument-cluster condition remained unresolved. A Mercedes-Benz dealer later documented a CHECK ENGINE condition and that the instrument cluster was showing dark, identified an instrument-cluster malfunction, and recommended further repair or replacement. I objected to taking back and operating a vehicle with an unresolved computer and instrument-display malfunction. I was concerned that losing access to speed, warning messages, or other critical information while driving could endanger me, my passengers, and other road users. I requested that the safety-related problem be fully diagnosed and repaired, but the vehicle was presented for return with the condition unresolved. The vehicle and its repair and diagnostic records should be obtained and examined to determine the cause of the electronic and instrument-cluster malfunction. The computer malfunction began approximately February 9-10, 2023.

The contact owns a 2015 Mercedes-Benz C300. While the contact’s son was driving approximately 20 MPH, the vehicle veered to the left and into the next lane when the brake pedal was depressed. The vehicle was cautiously driven back to the residence and parked. The vehicle was later towed to the local dealer to be diagnosed, and it was determined that the rear subframe had severe rust and was fractured and needed to be replaced. The vehicle was not yet repaired. The manufacturer was notified of the failure, but no assistance was provided. The contact was informed that the vehicle was not covered under the manufacturer’s extended warranty coverage for the failure. The failure mileage was 110,000.

Turn signals stop functioning during drive cycles. This functionality is lost for the remainder of the current drive cycle and can be restored with a key cycle. It does not occur every drive cycles and is unpredictable.

The vehicle was delivered to the dealer on July 13, 2026 at 33,360 miles with an illuminated check engine light. The dealer diagnosed intake camshaft timing faults and found pieces of the central valve screen in the engine oil filter. The camshaft bearing housing was replaced and the repair declared complete on July 15, but the check engine light returned the next day. On August 19 the dealer removed the cylinder head and found an internal oil passage that was restricted and clogged, which they stated may have caused insufficient oil flow and contributed to the camshaft timing failure. On August 24, Mercedes-Benz Engineering directed replacement of the complete engine. No replacement engine is available in the United States; one must be shipped from Germany, with a tentative arrival of October 19, 2026. The vehicle has been out of service since July 13, 2026 and is expected to remain out of service about four months. The engine is an M264 2.0L turbocharged four-cylinder. Similar cylinder head and camshaft failures have been reported by other owners of this engine at comparable mileage.

The vehicle was delivered to the dealer on XXX at 33,360 miles with an illuminated check engine light. The dealer diagnosed intake camshaft timing faults and found pieces of the central valve screen in the engine oil filter. The camshaft bearing housing was replaced and the repair was declared complete on XXX but the check engine light returned the next day. After extended diagnosis involving Mercedes-Benz Engineering and a Field Service Engineer, the dealer removed the cylinder head on XXX and found an internal oil passage that was restricted and clogged. The dealer stated this may have caused insufficient oil flow and contributed to the camshaft timing failure. On XXX, Mercedes-Benz Engineering directed replacement of the complete engine. The dealer advised that no replacement engine is available in the [XXX] and one must be shipped from [XXX], with a tentative arrival of XXX. The vehicle has been out of service since XXX and is expected to remain out of service for approximately four months. The engine is an M264 2.0L turbocharged four-cylinder. Similar cylinder head and camshaft failures have been reported by other owners of this engine at comparable mileage. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

My check-engine light recently illuminated, and diagnostic testing identified fault code P06DA00, relating to the oil pump control valve circuit. I have been quoted over $5,000 to replace the oil control valve and oil pump harness. I was quoted the following by Mercedes Servuce in Manchester, NH- Oil Pressure Regulator Valve: need to remove lower oil pan only to access oil control valve and replace the valve and sub harness. $5013.52. This is a known issue. My vehicle has been well maintained, and I have been advised that it is otherwise in excellent mechanical condition. I intend to keep and drive this vehicle for many more years, which makes it particularly disappointing to encounter a repair of this magnitude for a component that is not considered a routine maintenance or wear item.

My vehicle is subject to NHTSA Recall 26V216 involving the drive shaft universal joint. In March 2025, before the recall was announced, Mercedes-Benz of Carlsbad diagnosed my vehicle with a front driveline/drive shaft problem. I later paid $2,575 to have the drive shaft replaced using genuine Mercedes-Benz parts. Mercedes-Benz later sent me a recall notice stating that customers who already paid to correct the recall condition may be eligible for reimbursement. On May 27, 2026, I started the reimbursement process through Mercedes-Benz of Carlsbad. I submitted everything Mercedes requested, including the repair invoice, proof of payment, and documentation showing genuine Mercedes-Benz parts were used. When additional documentation was requested, I provided it. I was told I had submitted all required documents. However, Mercedes-Benz will not enter my claim into the reimbursement review process because the recall campaign is not yet “open” and the remedy is not yet available. Mercedes-Benz Star Support told the dealer: “Reimbursement can be claimed after campaign is in open status.” I escalated the issue with Mercedes-Benz USA and received the same answer. My concern is that this prevents the 60-day review process from even starting. 49 C.F.R. §573.13(g)(1) states: “The manufacturer shall act upon a claim for reimbursement within 60 days of its receipt.” If a claim is incomplete, §573.13 also requires the manufacturer to identify the missing documentation within 60 days. I was told I submitted everything required. I am not asking NHTSA to determine whether I am entitled to reimbursement or the amount. I am asking NHTSA to review whether Mercedes-Benz can accept all required claim documents but refuse to process the claim until the campaign becomes “open,” effectively postponing the 60-day process indefinitely. I do not need a future recall repair. I already paid to have my drive shaft replaced. My concern is that Mercedes-Benz has all the requested reimbursement