When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Wife left ignition in ACC for a few hours with lights on. Drained battery. We jumped car and drove home. I charged battery overnight. Battery Malfunction message still on dash. Battery was 3 years old so I went ahead and replaced. still no joy in extinguishing message. Battery voltage while running is 14.4VDC so Alternator is doing its job. Anyone have any ideas?
I am not infinitely familiar with your model, but nearly all models in your year and newer now use a Battery Control Module. It is an intelligent management system. When the battery is changed, the new battery data is read into the module, then it tracks battery performance from a voltage (charge health) AND a time standpoint. So, it's not as simple as just replacing the battery. The module needs to be reset too.
I can reset my module if/when I change my battery using one of my scan tools (Autel MX808). Not sure if it would work on yours, but I am pretty sure that is why you are still seeing the message. The dealer certainly can reset it, but not sure that's what you want to hear....LOL.
There also might be some combination of quirky button pushes, etc. that can reset it, but I've not spent time researching that. Google could unveil something if you try, and maybe before bringing it to someone with a diag. tool.
Chances are a quick scan job will resolve that pesky left-over message.
It's either the ECU or the F-SAM that's is nagging you to have a workshop look at this stored fault. Battery status is stored in the battery sensor on top of the NEG(-) post. Unplugging the Batt. sensor triggers an automatic battery relearn cycle, a good thing!
Personally I thought the F-SAM power management would have forced the car into sleep mode after 20mn or when low voltage got reached.
The positive side is you now have a known good battery and freshly rebooted car computers, all right!👍
Last edited by CaliBenzDriver; 12-18-2021 at 06:57 PM.
I agree this car seems to smart to let the battery sit in parking lot and die.If anyone has a favorite scanner that works well with MB I love to hear about it. I see several on Amazon, but not positive they will do what I need them to.