Mercedes EIS / EZS · Request an assessment

When the EIS/EZS is the likely cause

• The key is not recognised, or nothing happens when it is inserted.
• The electronic steering lock does not release.
• The starter does not engage although the battery is in order.
• Immobiliser fault codes appear after a battery or voltage problem.
• Water ingress or corrosion is visible at the connector.

The same symptoms can also come from the key, the steering lock or the wiring. Only a diagnosis shows which component is actually affected.

Clone, used unit or new unit?

Cloning transfers the data of your existing EIS/EZS to an identical replacement unit. This is only possible if the data of the original can still be read. A used EIS/EZS from another vehicle cannot simply be fitted: it belongs to the authorisation system of its donor vehicle. A new unit from Mercedes is ordered for your VIN and commissioned online.

FBS3 or FBS4

W204, W211, W221, the Sprinter W906, the Vito W639 and the W212 built up to 03/2013 use FBS3. FBS4 started with the W212 built from 04/2013, the C/A207 from 07/2013 and the CLS W218 from 09/2014, and applies throughout to W205, W213, W222 and later series. With FBS4, components are commissioned online via the Mercedes backend. We clarify the possible route for your vehicle before anything is shipped.

Please include in your enquiry

• Part number of the EIS/EZS (begins with “A”, printed on the label)
• Vehicle, model year and, if available, the VIN
• Whether the original unit still communicates with the diagnostic system
• How many keys you have
• Fault codes, if they have already been read