Why Can't the Mercedes-Benz Start Due to Protection System Failure?

[OEverett]

Possible causes of Mercedes-Benz protection system failure: 1. Damaged airbag. 2. Faulty seat belt sensor. 3. Damaged airbag sensor. 4. Anti-towing issue. Reasons why the car won't start are as follows: 1. Electrical or electronic failure: blown fuse, open circuit in high-voltage coil, open circuit in low-voltage circuit, detached central ignition wire, leaking distributor rotor, damaged spark plug. Electronic failure mainly refers to the malfunction of the central computer control board. 2. Fuel system failure: Symptoms include weak engine power and the accelerator pedal feeling like stepping on cotton. Possible issues include fuel pump failure, blocked fuel line, clogged fuel filter, carburetor malfunction, or damaged injector. 3. Mechanical failure: Broken timing belt (chain), cylinder leakage with no pressure, etc.

[StSimon]

I've been driving a Mercedes for several years and have encountered a few embarrassing situations where the protection system malfunctioned, preventing the engine from starting. Common causes include depleted key fob batteries or false triggers of the anti-theft system. Mercedes' anti-theft features are quite advanced—when the key fob battery dies, the system can't authenticate and locks the engine. First, try replacing the key fob battery; that’s likely the issue. If that doesn’t work, it could be a sensor or circuit failure, such as a faulty crankshaft position sensor putting the ECU into protection mode. I once tried fixing it myself without success and ended up having to visit the dealership to use an OBD scanner for decoding. Remember, don’t force repeated starts, as it might damage more components. For safety, calling a towing service is the most reliable option.

[MacLincoln]

From a repair perspective, Mercedes-Benz protection system activation preventing engine start typically involves anti-theft or engine management logic. The issue may stem from key ID mismatch, where the ECU cuts off ignition upon receiving incorrect signals. Check the key battery and contacts for oxidation; if normal, further test fuses and voltage stability to rule out power supply faults triggering protection. A diagnostic scanner is required to read trouble codes and identify the source, such as P0633 indicating anti-theft activation. Professional workshop handling is recommended, as they possess Mercedes-specific software for system reset. Avoid DIY disassembly to prevent wiring damage compromising overall vehicle safety.

[Adelyn]

Buddy, the same thing happened to my Mercedes last week - ignition failure with a protection system warning, totally freaked me out. Turned out the key fob battery had drained from prolonged inactivity. A new battery fixed it instantly. If your key is working fine, it might just be the electronic anti-theft system acting up, like signal interference nearby or bugs in older systems. Take it to an authorized Mercedes shop and have them scan the OBD codes to pinpoint the issue. Don't worry though, regular repair shops can handle this too - just don't delay and mess up your schedule. Towing service is super convenient, I used my roadside assistance card and it was free and hassle-free.

[CaliDella]

To prevent Mercedes protection failure from causing starting issues, regular system maintenance is essential. Replace key batteries periodically and check voltage every six months, while keeping anti-theft components clean. Avoid leaving the key in the car for too long after turning off the engine, as it may accidentally trigger the protection mode. During each maintenance, I remind technicians to check the key status and ECU updates. Newer Mercedes models also feature remote diagnostics, allowing quick diagnosis through scheduled services. In case of a malfunction, immediately stop attempting to start the car and contact repair services to avoid further damage. Vehicle safety design is beneficial, and proper maintenance ensures peace of mind during daily driving.