Battery control module faulty

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simoncollinge1

New Member
Joined
Dec 14, 2018
Messages
20
Location
Denbighshire
Car
E320
Hi over last six months have battery warnings displayed. Early ones “non essential switched off” then more recently Red picture of battery and go to workshop. Happens both when left standing for a week and when just overnight. Car has still started ok
messages then disappear.
checked batteries and alternator and all working fine.
Is the battery control module faulty?
E320 2004
Thanks
 
Classic symptoms of a failing battery.
Get the codes read to see what's going on
 
Would still suspect battery 🤓
 
And it is not battery fault if you have a current leak... ANY battery will surrender there at some point... measure your current draw.
 
The thing is the display showing a Red Battery fault is irregular. Some days it’s there, others not.. short or long journeys do not seem to make any difference. First thing in the morning, one day it shows a fault, another non…that’s why suspect a fault battery control module?
 
Not at all, could easily be the charging circuit. Very little to go wrong with the module but, anything can break..
I'd suggest getting the codes read using STAR.
 
You can check voltages using the dash computer, failing that, STAR, as whitenemisis says, or you can buy a cheap plug in tester from Ebay for a fiver, I've had one for yonks and it's still accurate. Voltages, ignition on but not running, 13+V, engine running after a few minutes, 14+V, the CANbus system is extremely sensitive to voltage drops, sadly the batterie's age doesn't count. Good luck.
 
Not at all, could easily be the charging circuit. Very little to go wrong with the module but, anything can break..
I'd suggest getting the codes read using STAR.
Slipping or slack serpentine belt? Slipping alternator pulley? Faulty alternator?
 
Sorted by fitting two new batteries. Old ones only 5 years old.. Thanks for all your comments
 

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