2003-09 Mercedes-Benz E-Class Auxiliary Battery Replacement

This guide provides instructions on how to replace the auxiliary battery on 2003 through 2009 Mercedes-Benz E-Class vehicles. Applicable to models such as E320, E350, E500, E55 AMG, E63 AMG. 


  • Auxiliary battery malfunction on the dashboard
  • Battery protection: Convenience functions temporarily unavailable

What you will need


  1. Open the hood and locate the auxiliary battery in the right side of the engine bay. 
  2. Remove the 10mm plastic nut from the cabin filter housing. w211 auxilary battery location
  3. Remove the 10 mm nut from the top bracket. Lift up the bracket. w211 e class aux battery bracket
  4. Remove the 10mm bolt from the negative battery terminal. neg positive  w211 aux battery
  5. Remove the 10mm bolt from the positive battery terminal. Be extremly careful so that the positive cable does not come in contact with any metal parts.  
  6. Remove the old battery and place the new battery in place. Connect the positive cable first. Connect the negative cable last. Spray battery terminal protector on the battery post to prevent corrosion. Install the cabin filter lid. w211 aux battery installed


No programing or coding is required. Once you replace the auxilary battery on your W211 E-Class, the warning message should disapear from the dashboard.


Stephanie , 2018-12-28

My local shop wanted $195 to replace the auxiliary battery on my 2005 E500. This is so easy I plan on doing it myself.

Jesus , 2018-12-30

Very good step by step guide. Thanks for sharing.

Timothy, 2019-07-05

What's the model number for a axillary battery for 2003 e320

By YOUCANIC on Aug 9, 2019


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