Mercedes Benz Electronic Ignition Switch
Mercedes Benz EIS/EZS and Key
EIS in a Mercedes Benz stands for Electronic Ignition Switch, also known as EZS, and it is a core component of the vehicle's anti-theft and start authorization system. It is the electronic control module that replaces the traditional mechanical ignition lock, responsible for verifying the key and authorizing the engine to start, and in earlier models acts as a gateway for vehicle network communication.
The key functions of the EIS are:
Key authentication: It verifies the infrared coded key with a handshake between the key, the EIS, and other control units to ensure it is authorized to start the vehicle.
Immobilizer system: The EIS is the central part of the immobilizer, preventing the engine from starting without the correct key.
Vehicle network communication: In earlier models, the EIS acted as a network gateway, directing traffic between different control modules on the vehicle's CAN network.
Ignition control: It controls the flow of power to the starter motor and other systems based on the key's authentication.
Common trouble codes and symptoms
B1000: Indicates an internal malfunction within the EIS module itself.
B1703: Signifies a communication failure between the EIS and the Electronic Steering Lock (ESL).
B1F00: Means the EIS is not recognizing the key.
A22449: EIS malfunction.
A25407: ESL (Electronic Steering Lock) malfunction.
Other symptoms:
Key won't turn in the ignition.
Instrument cluster lights fail to illuminate.
Car won't start.
Key works intermittently.
Push-start button malfunctions.
To diagnose and fix use a diagnostic tool. Connect a Mercedes-specific tool, to the OBD-II port to read specific fault codes (Diagnostic Trouble Codes-DTCs); alphanumeric codes generated by a vehicle's On-Board Diagnostics (OBD-II) system to identify malfunctions, test the key to see if the problem is with the key itself or the EIS module. It's possible both keys can fail if the EIS is the problem. Consider other causes like water damage from spills or incorrect jump-starting procedures can also cause EIS issues. Seek professional help since diagnosing and repairing EIS problems can be complex, so it's best to consult a professional technician.
A failed EIS module typically needs to be replaced. The Adaptation of used EIS/EZS modules or 2nd hand EIS/EZS module its possible. The module its reset first to factory default data (renew or virgin state) so that it can be reuse for another car and then personalize and activate. To personalize, the data from the Original EIS module it is transfer over to the new one or using the FBS data from the ECU when the original EZS is missing or broken
FBS data on a Mercedes Benz refers to the Fahrberechtigungssystem (Drive Authorization System), an encrypted system that controls the vehicle's ignition and keys. This is a critical security system with different versions (like FBS3 and FBS4) that handle key programming, vehicle diagnostics, and component adaptation
If you are replacing an EZS/ EIS and you see that the EZS/ EIS is a spare part (when you read the FBS DATA it will be displayed) this means that the EZS/ EIS has been disabled from factory and cannot be personalized or renew any more. This EZS/ EIS cannot be used for replacement.
Mercedes Benz EIS-EZS and Key
Mercedes Benz EIS EZS Electronic Ignition Switch
