Mercedes Motorola EIS Diagnostic and Repair Guide

Here we will share some useful tips for diagnosing and repairing Mercedes Motorola EIS.Hope these will help you.


  • First thing is to read and back-up the EEPROM data,this is usual way.
  • Connect the EIS to a bench power supply with display for the current for testing. Monitoring the current EIS help you to evaluate the condition,even 1mA difference points will leads to a problem. Also the behaviors thru different stages can be observed when inserting the key, when it goes to sleep mode, etc.
  • Reading the dump from EIS by tools like VVDI MB Tool, then run it using MB SKC key calculator to verify the dump’s correct. If it looks weird, read again to verify.
  • Connect to a power supply and test the function before starti any work on the EIS. Even if there is no original working key another key can be inserted to verify the correct function,which will help you know whether a subsequent failure has occurred after your intervention or before.
  • Please confirm the key you programmed is fully functional.
  • It is good to have a similar EIS handy to make comparisons on the board, the current it draws and eventually to erase the EEPROM.