Clone Mercedes EZS
The Electronic Ignition Switch (EZS) is the heart of the Mercedes immobiliser. We clone defective EZS units with a complete diagnosis via the original Mercedes diagnostic system — the only method that captures all data regions reliably.
What is the EZS / EIS?
The EZS (Elektronisches Zündschloss) — also known in English as the EIS (Electronic Ignition Switch) — is the central immobiliser control unit in Mercedes-Benz vehicles. It sits in the steering column, communicates with the inserted key via transponder technology and only releases the vehicle after correct key recognition.
The EZS is simultaneously coupled to the ESL (Electronic Steering Lock) and the engine control unit. If it fails, the vehicle becomes undriveable — the key can no longer be turned or the vehicle will not start even though everything is mechanically in order.
Typical EZS failure causes
- Water ingress in the steering column area
- Corrosion at EZS contacts / key contacts
- Mechanical wear after many key insertion cycles
- Electronic fault in the EZS processor
- EZS security lock after theft attempts
- Communication fault EZS ↔ ESL
Why manufacturer diagnosis before cloning is decisive
Without manufacturer diagnosis
- EZS is cloned "blind" — without knowledge of the data status
- Undetected data faults are transferred onto the replacement EZS
- Possible incompatibility between EZS and ESL version
- Hidden security lock remains active after cloning
- Key transponder roles corrupted — vehicle not startable
With original manufacturer diagnosis (KFZ Dietrich)
- Complete EZS diagnosis before start: all data regions visible
- Immobiliser status and key roles documented before cloning
- ESL coupling verified: compatibility with replacement EZS confirmed
- Security lock identified and reset if necessary before data transfer
- Final test with the original Mercedes diagnostic system: function confirmed
Supported Mercedes series
Further series (W203, W164, W166 etc.) on request. We clarify the EZS generation and compatibility before accepting the order.
Process: cloning a Mercedes EZS
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Diagnosis with the original Mercedes diagnostic system
Before every cloning we carry out a complete EZS diagnosis with the original Mercedes diagnostic system — component status, communication faults, immobiliser status. Only this way can we judge whether cloning is the correct solution.
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Assessment: cloning or re-coding?
The original Mercedes diagnostic system shows whether the EZS data memory is intact. If yes: cloning onto a tested replacement EZS. If not: re-coding with SCN programming. We choose the right approach.
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Read and back up EZS data
Complete read-out of all EZS data regions: transponder data, ELV coupling, key roles, VIN binding, immobiliser status. A safety copy is created.
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Clone onto replacement EZS
Transfer of the complete EZS data onto an identical, tested replacement EZS. The replacement unit receives your exact vehicle signature — no re-coding in the vehicle required.
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Functional test & return shipment
Final verification with the original Mercedes diagnostic system: immobiliser active, key recognition correct, ELV synchronised. Insured return via DHL with installation guide and written findings report.
EZS cloning — scope of service
EZS cloning Standard
- Incoming diagnosis with the original Mercedes diagnostic system
- Read EZS data
- Clone onto replacement EZS
- Final test with manufacturer diagnosis
- Return shipment DHL insured
EZS cloning Advanced
- Incoming diagnosis with the original Mercedes diagnostic system
- Read EZS data
- Clone onto replacement EZS (Gen. 3/4)
- Verify ESL coupling
- Final test with manufacturer diagnosis + SCN protocol
- Return shipment DHL insured
EZS + new keys
- Diagnosis with original Mercedes diagnostic system
- EZS re-coding SCN
- Key learning procedure
- All keys lost: possible
- Final test with manufacturer diagnosis
🔬 Technical details: EZS generations and data structure
The Mercedes EZS was installed in several generations. The data regions differ considerably depending on the generation:
- EZS Gen. 2 (Motorola HC12 based): Found in the W211 and Sprinter W906. Relatively simple data structure. Key transponder: up to 8 key roles. ELV coupling via LIN bus.
- EZS Gen. 3 (Freescale HC12 / 68HC12): W204, W212, early W221. More complex security structure, FBS4-compatible. XENTRY required for correct key role evaluation.
- EZS Gen. 4 (32-bit processor): Later W221, W212 facelift. Full XENTRY SCN coding required for all cloning work.
During cloning the following data regions are transferred: transponder EEPROM (key roles 1–8), NEC controller region, ELV sync register, VIN binding region, security block status.
Blind cloning without prior XENTRY analysis risks transferring an active security lock onto the replacement unit, or overlooking an ESL version incompatibility — either results in a vehicle that cannot be started.
Nationwide send-in service
KFZ Dietrich GmbH & Co. KG
📍 Meckelstraße 8, 37181 Hardegsen, Germany
🕐 Mon–Fri 07:30–16:30
🌍 Nationwide send-in service
Request an EZS cloning order
Tell us the series, year of manufacture and fault description — we will respond with a diagnosis plan and a fixed price.
Request EZS order now