Mercedes EIS / ESL
Mercedes EIS / ESL


Mercedes Benz owners may face a problem with Mercedes EIS / ESL Services preventing starting the vehicle. This is often caused by a damaged/defective key, a failing/failed Electronic Ignition Switch (EIS), or a bad Electronic Steering Lock (ESL). When a key is inserted into the EIS the immobilizer system will instantaneously carry out a check to see if it’s a correct “programmed” key that has been inserted. The EIS will verify with the ESL and Engine ECU to check that it is the correct key and if the units agree it will authorize the vehicle to be started.

Solutions to the Ignition Switch Problems

First of all, if you have another key for that vehicle check if you experience the same symptoms with the spare key as it could have been caused by a defective key and not a failing Mercedes EIS / ESL module.

Another option would be to get the EIS/EZS tested and either repaired or replaced with a unit from a donor car. A donor unit would need to be programmed to the vehicle so that the stored VIN is matched in all modules.

We are able to offer testing for Mercedes EIS / ESL service as well as programming replacement donor units.


Mercedes Dealership would advise you to purchase a new unit as the EIS Module cannot be repaired or reflashed using the Mercedes Diagnostic System. That’s not necessarily the only available solution anymore. ​Give us a call at 832-598-1144 or get in touch via our website.

  • Key won’t turn when inserted into the ignition.
  • Key won’t turn in the ignition during cold weather.
  • Key turns in the ignition but the car won’t start.
  • ntermittent key faults and non start.
  • Key turns the ignition but dashboard doesn’t turn on.
  • Unable to unlock the Steering Lock.

We offer a full range of Mercedes services to vehicle owners in Houston and surrounding areas. Our professionals know how to handle a wide range of Mercedes services.

  • Low Battery Voltage
  • Power Surge
  • Connecting jump-starting cables while the key is in the ignition.
  • Corrosion/faulty processor.
  • Same day service for most repairs and maintenance
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