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w220 electrical problems after flat battery. s350 petrol

Discussion in 'Electrics, Vacuum, Ignition and ECU' started by bonchester, Mar 25, 2020 at 5:58 PM.

  1. bonchester

    bonchester New Member

    Messages:
    8
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    Joined:
    Apr 17, 2018
    Your Mercedes:
    s class. 350 petrol
    been having problems with battery drain which resulted in a totally flat battery. I charged the battery,reconnected and then the problems started. The engine cranked but didnt start after that numerous malfunctions appeared, abs, stability control etc. The electric cooling fan started to run stop start and then the engine would not crank at all.
    Has anyone any ideas please or remedies?
     
  2. Botus

    Botus Senior Member

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    Joined:
    Jul 29, 2014
    Location:
    UK
    Your Mercedes:
    S500/2010/500
    its normal on this era's electrics - they like to give issues.

    you need someone with good diagnostics to nurse maid it back to good health. Likely needs a new battery and a few hours clearing and resetting stuff (mind u it will go flat again even with a brand new battery as you try to reset stuff, so need a power supply as you go) or you'll get nowhere as it'll die on you again and bring the faults you just cleared back again.

    also if there any damp in the can bus (front passenger footwell a good starting point) this will be something you'll need to resolve.... you might also have some frazzled modules, they were all a bit too delicate for their own good, or got rather soggy in all the rain we've been having

    without STAR and an experienced helper and a big power supply.... you'll probably just get stressed out
     
    Last edited: Mar 25, 2020 at 10:53 PM
  3. mersum1es

    mersum1es Senior Member

    Messages:
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    Joined:
    Sep 25, 2010
    Location:
    Finland
    Your Mercedes:
    W212/-09/350CDI, W219/-07/320CDI, W220/-01/320CDI, EX:W211/-04/320CDI, EX:W210/-01/270CDI
    check no fuses blown, check that battery didn't die totally (cooling fan sounds indicating lack of voltage)
     
    bonchester likes this.
  4. mioba

    mioba Senior Member

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    Joined:
    Feb 19, 2006
    Location:
    Nottingham
    Your Mercedes:
    W124/1994/E200, W220/2004/S320CDI, W205/2016/C200, W447/2017/3.0 CDI
    You didnt spark the battery when replacing did you.
    Whats the voltage showing on the charged battery.
    W220 hate low battery, eps, pre-safe, command all inoperative until the battery is 100%
     
  5. OP
    bonchester

    bonchester New Member

    Messages:
    8
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    1
    Joined:
    Apr 17, 2018
    Your Mercedes:
    s class. 350 petrol
    thanks to all for your replies. The battery is the culprit,i didnt quite realise it was at its end as it hasnt been holding any charge at all. Just standing overnight,not connected,drops to below 10. Even though i had charged it fully it was not up to the task apparently. New battery solved it.I know i should have gone down that route at the start. Once again thank you.
     
    daibevan likes this.

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