amgboy916

i have a 2012 cls 63 with 55k miles
i was driving and i had that dreaded eco mode on and my car shut off at a stop and then wouldnt start again!

now my car wont start at all it wont even crank ive tried to jump start it multiple times it has power and the key unlocks and locks the car fine and i can put key into the igniton and twist it fully but it will not crank at all i tried my spare key as well and same thing
i tried changing the battery on the keys as well.

please help im frustrated theres no error codes or anything this car shouldnt be doing this i just got it 3 months ago

im really trying to avoid towing it to the dealership but i may have to

6speeddave

Sounds like a bad battery.

amgboy916

really? Even if all other electrical components work? And i tried jump starting it with an SUV twice. Should i remove the battery and tske it to autozone to get that ruled out?

Mikeki7

What battery are you trying to jump start? The one in the trunk or the one under the hood? The trunk battery is for accessories while the hood battery is for starting the car, you should be jump starting that one.

6speeddave

There is a chance the battery is the wrong kind (non-AGM), it happened to me and happens more often then not. You said you've only had the car 3 months. The battery is always the first thing to check. If the auxiliary battery failed you would have had prior messages well before it actually failed and doesnt really affect the car starting or not. The last thing to check would be the alternator but I doubt that its bad, the car is only 5 years old.

sambam2006

A few things to check:

If eco mode on and car goes off and doesn't start, make sure you put in 'P' position before attempting to restart the car otherwise the key will turn with no crank.

Battery seems to be the main issue but to be honest but again we don't want to rule other things out at the same time, your car has two batteries, one in the front bonnet which is the big main battery and the one in the trunk is the auxiliary battery.

Ge the battery checked by dealer, you could also try this in the mean time open the Mercedes me app to see battery voltage.

TTMerc

check the terminals on the main battery. Check also the ground to the chassis make sure no corrosion and good contact.

amgboy916

I appreciate all the battery tips i tried jump starting already and charging with a trickle charger but no luck

haven't checked volts yet but can battery be ruled out if those haven't worked? I'm about to get it towed to the stealership tomorrow. I'm about ready to give up i checked the fuses and relays all are good too

amgboy916

Is it supposed to be agm or non agm?
its a benz battery in there that came with it but im not sure if its agm or not

6speeddave

It is supposed to be AGM. If its mercedes branded then it should be. Remember the main battery is up under the front hood (passenger side), and the auxiliary battery is in the spare tire well in the trunk. Dont confuse the two.

Mikeki7

If it doesnt crank even when jump started I dont think its the battery. Did you check it with a multimeter yet?

JDMAP1

So what's the verdict/diagnosis?

amgboy916

It turned out to be the starter. It was pretty expensive and not covered under warranty lol