Electronic Ignition Switch (EIS/EZS) Repair 

The Mercedes-Benz Electronic Ignition Switch (EIS), also known as the Electronic Ignition Starter Switch (EZS), is a key component in the vehicle’s anti-theft and starting system. It works in conjunction with the vehicle’s smart key to verify authorization before enabling engine start-up. When a valid infrared smart key is inserted into the ignition slot, the EIS module and the key exchange rolling security codes. Once validated, the EIS allows communication with the vehicle’s Electronic Steering Lock (ESL) and the Engine Control Unit (ECU), enabling the ignition to turn on and the engine to start.

 

Over time, the EIS module can develop faults that lead to starting issues or complete ignition failure. These faults are more common in high-mileage vehicles or those exposed to frequent key cycling. Common symptoms of EIS failure include the key not turning in the ignition, intermittent starting issues, no response when inserting the key, or dashboard lights not illuminating. In some cases, the steering lock may also fail to disengage, further preventing the car from starting.

 

There are several causes of EIS failure. Internal circuit board damage, failed solder joints, EEPROM data corruption, and communication errors between the EIS and other modules are frequently observed. Faults may also occur due to water ingress, voltage spikes, or improper battery jump starts.

 

At Eurotronix in Perth, we specialise in the diagnostics, repair, and replacement of faulty Mercedes-Benz EIS modules. Our team uses advanced programming and coding tools to accurately identify issues and offer effective solutions—often at a fraction of dealership prices. We can clone data from your faulty EIS to a new or donor unit, preserving your vehicle’s security and key programming without the need for costly reprogramming.

 

We service most Mercedes-Benz models, including the C-Class, E-Class, S-Class, ML, GL, and Sprinter vans. With years of experience and a strong reputation in electronic vehicle repairs, Eurotronix is your trusted choice for Mercedes ignition switch problems. Our services are available in our Perth workshop or via mobile service, reducing your downtime and towing costs.

 

If your Mercedes is experiencing ignition problems, contact us today for a professional diagnosis and fast, reliable repair.