W211 visit workshop red battery

Discussion in 'Electronics' started by foru2justnv, Jan 27, 2017.

  1. foru2justnv

    foru2justnv Member

    Messages:
    43
    Joined:
    May 18, 2011
    Location:
    West sussex
    Car:
    Mercedes w211 E320 CDI s212 e220cdi
    Hi all
    W211 e320cdi. Had a red warning light on now for a while so thought id buy some new batteries.
    Bought a new 019 battery for the rear and a ytx14 for the front.
    I have checked the polyfuse and it was good.
    Checked the wiring from bcm to polyfuse and the both had continuity. Changed the aux battery relay as they were cheap.

    Just today installed smaller battery at front and surprised to see the red battery light hasnt dissappeared.
    Have I missed something.
    As per instrument cluster ive got good voltage before and after start up.
    Any help much appreciated
    Tiff
     
  2. OP
    OP
    foru2justnv

    foru2justnv Member

    Messages:
    43
    Joined:
    May 18, 2011
    Location:
    West sussex
    Car:
    Mercedes w211 E320 CDI s212 e220cdi
    Would a faulty bcm trigger the light?
     
  3. whitenemesis

    whitenemesis MB Club Veteran

    Messages:
    14,085
    Joined:
    May 7, 2007
    Car:
    Lexus RC300h F-Sport 2016
    A faulty BCM may trigger the warning , as could a failed alternator regulator pack.

    You really need to get the car on STAR and have the codes read..
     
  4. Auto-mobile

    Auto-mobile Hardcore MB Enthusiast

    Messages:
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    Oct 1, 2011
    Location:
    Birmingham
    Car:
    2x c43 Amg clio 172 turbo 314bhp
    Probably the alternator.
     
  5. OP
    OP
    foru2justnv

    foru2justnv Member

    Messages:
    43
    Joined:
    May 18, 2011
    Location:
    West sussex
    Car:
    Mercedes w211 E320 CDI s212 e220cdi
    Hi Thanks for your replies. I have been monitoring the alternator output while driving and also witha voltmeter. Im consistantly getting 14.0v so the alternator checks out fine. Plus its never drained or gone flat since ownership. Previous rear battery was fine I changed it thinking it was that but that was 3 months ago.
     
  6. Auto-mobile

    Auto-mobile Hardcore MB Enthusiast

    Messages:
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    Joined:
    Oct 1, 2011
    Location:
    Birmingham
    Car:
    2x c43 Amg clio 172 turbo 314bhp
    You may have to have fault codes erased after fitting the batteries, had that on a sl once.
     
    1 person likes this.
  7. OP
    OP
    foru2justnv

    foru2justnv Member

    Messages:
    43
    Joined:
    May 18, 2011
    Location:
    West sussex
    Car:
    Mercedes w211 E320 CDI s212 e220cdi
    Will give that a try tomorow. Let you know thanks
     

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