Main Battery Issue?
Thread Starter
Senior Member
Joined: Jul 2019
Posts: 443
Likes: 91
CLS400 4Matic EC Tuned
Main Battery Issue?
Hey Everyone,
When I press push to start, the car cranks and gives up. If I take out the button and insert the key and start it, it works. I’ve changed the battery in the key fob, but that hasn’t helped.
Yesterday, it failed to start with the button, and even with inserting the key it failed to start, there wasn’t even a crank. So I hooked up a jump starter, and the car turned on with the button. Is this a symptom of the main battery failing?
I believe this car battery is the original from 2015 as I purchased the vehicle in mid 2019 and I don’t see anything on the Carfax prior to that where the battery was changed. I’ve always maintained this battery with an 8 amp battery charger and I have it hooked up now so it’s good for tomorrow. I did notice that after about 10 hours of charging, the voltage reads 13.8V. In the past, this would often read 14.7V or it would say FUL.
When I press push to start, the car cranks and gives up. If I take out the button and insert the key and start it, it works. I’ve changed the battery in the key fob, but that hasn’t helped.
Yesterday, it failed to start with the button, and even with inserting the key it failed to start, there wasn’t even a crank. So I hooked up a jump starter, and the car turned on with the button. Is this a symptom of the main battery failing?
I believe this car battery is the original from 2015 as I purchased the vehicle in mid 2019 and I don’t see anything on the Carfax prior to that where the battery was changed. I’ve always maintained this battery with an 8 amp battery charger and I have it hooked up now so it’s good for tomorrow. I did notice that after about 10 hours of charging, the voltage reads 13.8V. In the past, this would often read 14.7V or it would say FUL.
Out Of Control!!
Joined: Apr 2019
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Hey Everyone,
When I press push to start, the car cranks and gives up. If I take out the button and insert the key and start it, it works. I’ve changed the battery in the key fob, but that hasn’t helped.
Yesterday, it failed to start with the button, and even with inserting the key it failed to start, there wasn’t even a crank. So I hooked up a jump starter, and the car turned on with the button. Is this a symptom of the main battery failing?
I believe this car battery is the original from 2015 as I purchased the vehicle in mid 2019 and I don’t see anything on the Carfax prior to that where the battery was changed. I’ve always maintained this battery with an 8 amp battery charger and I have it hooked up now so it’s good for tomorrow. I did notice that after about 10 hours of charging, the voltage reads 13.8V. In the past, this would often read 14.7V or it would say FUL.
When I press push to start, the car cranks and gives up. If I take out the button and insert the key and start it, it works. I’ve changed the battery in the key fob, but that hasn’t helped.
Yesterday, it failed to start with the button, and even with inserting the key it failed to start, there wasn’t even a crank. So I hooked up a jump starter, and the car turned on with the button. Is this a symptom of the main battery failing?
I believe this car battery is the original from 2015 as I purchased the vehicle in mid 2019 and I don’t see anything on the Carfax prior to that where the battery was changed. I’ve always maintained this battery with an 8 amp battery charger and I have it hooked up now so it’s good for tomorrow. I did notice that after about 10 hours of charging, the voltage reads 13.8V. In the past, this would often read 14.7V or it would say FUL.
They are available all over the place at various prices from $800 installed to $175 carry-out and in between.
MBWorld Fanatic!
Joined: Oct 2019
Posts: 5,152
Likes: 1,766
From: Colorado
G550
If you've had 6 years of service from a battery that was already 4 years old when you acquired it, consider yourself lucky. You can buy a top quality battery for less than $250 and install it yourself in 30 minutes.
Thread Starter
Senior Member
Joined: Jul 2019
Posts: 443
Likes: 91
CLS400 4Matic EC Tuned
FYI - it was a main battery issue. I’ve seen a couple of these threads but nobody posted their solution. Took a look at my Carfax and the battery was replaced in 2017 so it was 8 years old.
Junior Member
Joined: Nov 2024
Posts: 43
Likes: 8
From: Phoenix, AZ
2014 CLS550 4MATIC M157 swap, MBH Tuned
WOW, good to know that. I'm about due for a new battery too. My Carfax shows mine was changed in 2020 heard AGMs can last 5-6 years. Your up keeps makes me see I should buy a battery tender.
Thread Starter
Senior Member
Joined: Jul 2019
Posts: 443
Likes: 91
CLS400 4Matic EC Tuned
Also wanted to point out that my auto start stop works again. The first stop after installing this new battery the car immediately turned off. I would charge my old battery to full and even then it wouldn’t work. Haven’t had this function working since like 2021. I don’t use it though as it’s kind of pointless.
Junior Member
Joined: Nov 2024
Posts: 43
Likes: 8
From: Phoenix, AZ
2014 CLS550 4MATIC M157 swap, MBH Tuned
Mine did this as well. Wished I waited longer to change out both batteries. I was sitting at Chevon and the car just shuts off. It scared me thinking my car just died. I forgot to shut off the ECO button. It was nice to not have to turn off the system every time. I know it's not hard to reach over to push the button <---I'm that lazy. It's just a waste to me plus the extra I feel wear and tear on components.
