What is the reason for the self-recovery of a Mercedes 48V motor fault?
3 Answers
System "bug" causing false alarms. Below is an introduction to Mercedes' 48V system: 1. Introduction: The Mercedes 48V system increases the vehicle voltage to 48V. Components like the air conditioning compressor and power steering pump, which were previously driven by the engine, have been converted to electric drive. Additionally, a larger battery is used, and a higher-power integrated motor is added between the engine output and the transmission. 2. Function: The main role of the Mercedes 48V motor is to start the vehicle and perform kinetic energy recovery. During low-speed stop-and-go driving, it can directly drive the vehicle without starting the engine, and it can also assist the engine in power output during acceleration. Core components include the 48V battery, 48V starter motor/generator, a 48V/12V (DC/DC) voltage inverter, and corresponding control modules. If the motor fails, it is recommended to visit a 4S store for repair as soon as possible.
When I used to drive a Mercedes-Benz E-Class, I encountered a similar situation where the 48-volt motor fault light suddenly came on, and the car displayed a warning, which made me quite nervous. However, after parking and starting the car again the next day, it inexplicably returned to normal, as if nothing had happened. I suspect it might have been a software bug, where the Mercedes control computer occasionally triggers false alarms, or perhaps a loose wiring connection that reconnected after some vibration. These temporary issues are quite common, especially during frequent stop-and-go traffic in the city. The 48-volt system is responsible for mild hybrid functions, such as start-stop and assisted acceleration, so even minor glitches can have a noticeable impact. However, just because it resolves itself doesn’t mean you should ignore it—safe driving is paramount. Later, I still took it to the dealership to scan for error codes to ensure it wasn’t a serious underlying issue. Regular maintenance checks can prevent many such problems.
When working at the repair shop, I've handled many Mercedes-Benz cases. The reason the 48-volt fault light disappears on its own is mostly due to temporary signal interference or voltage instability. The Mercedes system is very intelligent—error codes flashing briefly could be caused by sensor misjudgment, excessive dust at connection points, or circuit overload protection triggering and then resetting. I recommend owners first check the battery status and charging system, as it controls the entire 48-volt network. A common issue is loose connectors that automatically reset after bumps. I'd suggest using a diagnostic tool to check historical fault records—if there are no traces, it's generally fine. However, hardware aging like motor winding damage will cause recurring issues. Don't wait until a breakdown on bad roads to fix it—simple preventive measures like replacing fuses can save big money.
