Mercedes Benz EIS immobiliser ignition repair service

Mercedes Benz EIS immobiliser ignition repair service


This is a repair service for all Mercedes Benz electronic ignition units, also known as EIS/EZS unit.

You will need to remove and send us your ignition unit and we will diagnose and repair any fault you may have with it.
We will need you to also send all keys you have for the vehicle with the unit.
No need to replace your EIS at a great cost, we can save you money.

One of the most common faults is that the EIS no longer recognizes the key, this prevents you from turning the key and starting the engine.

All Mercedes Benz models covered.
Mercedes A-Class (W169) 2004-2010
Mercedes B-Class (W245) 2005-2010
Mercedes C-Class (W203) 2003-2007
Mercedes C-Class (W204) 2007-2009
Mercedes CL-Class (W215) 2001-2006
Mercedes CL-Class (W216) 2005-2009
Mercedes CLK-Class (W208) 2001-2002
Mercedes CLK-Class (W209) 2003-2008
Mercedes CLS-Class (W219) 2004-2009
Mercedes E-Class (W210) 2001-2002
Mercedes E-Class (W211) 2002-2007
Mercedes E-Class (W212) 2009-2010
Mercedes G-Class (W463) 2002-2009
Mercedes GL-Class (X164) 2006-2009
Mercedes M-Class (W164) 2005-2009
Mercedes R-Class (W251) 2005-2009
Mercedes S-Class (W220) 2001-2005
Mercedes S-Class (W221) 2005-2009
Mercedes SL-Class (R230) 2001-2009
Mercedes SLK-Class (R171) 2004-2009

Mercedes Sprinter (W906) 2005-2009
Mercedes Viano (W639) 2004-2009
Mercedes Vito (W639) 2004-2009
Meredes Vito W447 2015 +


Please note that prices are from £150 +vat depending on the exact fault we find, price may be more. (You will be informed before hand if you wish to proceed.)

Mercedes EIS / EZS Immobiliser Key Module Problems and Repairs

Symptoms we can diagnose and repair are:

  • Unable To Turn The Key
  • Unable To Start The Car
  • Turn The Key – But Car Won’t Start
  • Intermittent Ignition Key Faults
  • Vehicle not responding to remote

If the EIS unit becomes faulty, the key will not turn & start the engine, this function will be de-activated and the module will be locked for security purposes. This will stop the engine from starting. It is very unfortunate but also a very common problem as there are many reasons as to why these units fail. Some of the most common reasons are listed below:

  • Jump Starting Whilst Key Is Inserted
  • Power Surge
  • Low Battery Voltage
  • Damage to key
  • Damage to eis

All of the above can cause memory loss or corruption of the EIS module and it cannot be repaired or re-flashed using the usual Mercedes diagnostic systems. At this point most people will advise you to purchase a new ignition unit which can work out extremely expensive and will need programming and coding before it will work
We also provide a replacement eis unit service, we can send you a reconditioned unit fully programmed to your car ready to install and drive should your original eis be beyond repair.


***Please note all EIS repairs take Between 5 – 7 days***

We have a standard check up fee of £60 +vat if we find nothing wrong with your unit or key after testing