jerellorenzo

Hi Forum,
First not an idiot, all things point to dead battery because a dome light or something was on from 9pm to about noon the next day. In large i'm just trying to negate the anxiety that i managed to destroy my baby by disconnecting the battery.
2012 cls550 4matic blue efficiency - i think that's a M278 ? and that designation and my vehicle aren't actually on any of the lists - not sure why, this is the early lineage of AMG GT - ya know the one we all spurt over...
B1 service I changed the right plugs - took it for a spin, all was well. Left plugs i decided to disconnect the negative battery terminal in the front ( for safety.)
doors had been gently opened and closed as the windows don't move without a battery.
morning comes i finish up the plugs, go to the battery - see the negative terminal leaning on the post - so presumably the door was open and the light killed the battery.
So i put a meter on the battery 4 volts - car is dead as a doornail with the terminals connected.
Throw the battery on a charger for a while with the terminals off, gave it a bit, terminals on got in the car, car was mostly alive this time, used the key in ignition over the button and at that point it almost cranked over.
Presumably again terminal slid over to the battery and the lights turned and killed the battery. Battery otherwise was seemingly great, it's 88 degrees out, battery is 2021.

Anyway so i started looking and i'm curious if I somehow destroyed my car by disconnecting the battery? Seems stupid question. it's a 2012, not hybrid anything to screw up as far as i'm aware.

So it's still on the charger, slow charge at 2amps.
I don't have a jump pack, tempted to call AAA just to know one way or another.

Beyond that, my WIS has the indexes for the articles about removing the vacuum pump ( left side on the back of the valve cover ) - as that o-ring is leaking on the exhaust and that will eventually catch on fire if neglected.
I'll make another thread for that. Youtube and google no longer serve any function beyond how NOT to do anything ever.

thoughts? I'll update later tonight as the meter is at 75% once it says 12.5v on the meter i figure the car should start.
no corrosion or anything.

thoughts?

Baltistyle

if it’s really at four volts and won’t seem to charge, look up the procedure for resurrecting a battery too low to charge. It involves connecting two batteries (one good with the one bad) overnight so they balance at a higher average, then it can take the charge. Many batteries won’t take a charge below six volts (or so Ive been told, and personally witnessed)

jerellorenzo

Well the good news is the battery took a charge, and the car started.
The bad news is NONE of my fancy electric features work.
no touch door unlock, no auto park, no mirror shifts down when in reverse, and that's all i've noticed thus far, but seemingly disconnecting the battery has removed all my luxury.
Any thoughts?

jerellorenzo

Thanks for responding. The battery charged. Drove the car around. All the bells and whistles are back except for park assist, the auto reverse mirror just started working after about 20 minutes of driving around and another stop start. I have a feeling the battery is on it's way out, it was aftermarket - only had the car 2 years and it's been covered in the driveway for at least 1/3 of that. I assume the voltage is insufficient to allow for autopark as i bet the draw on moving the steering wheel with all the sensors makes sense. I'm just going to suck it up and pay the $1000 to get the vacum pump seal replaced. I'll give one last update after the dealer with all the resolutions.

I still don't know exactly how the battery died, and have not hooked up the xentry to clear any codes, which i will do before it goes to the dealer IF it doesn't start working again. As far as the car being destroyed from the battery, the aux battery probably plays into things.

Otherwise my clock reset, all my presets are there. everything works except park assist, which just doesn't activate when put in reverse as it should with teh blue P on