C43 Battery Replacement Instructions
I feel a little dumb for asking this, but are there any precautions I need to take and steps I must do?
I've changed batteries in cars before, but never in one so complex as a C43.
I have seen some old videos on Youtube that say the ECU will have to be reset, and I know there's a constant power battery too.
Can anyone give me the steps or best practices to change out the main cranking battery?
Thanks in advance!
It seems an excessive cost and would like to ask you if you were able to replace it by yourself and reset the ECU? and if you can lead me in the right direction.
thank you in advance
I had to have the battery replaced after a few months. Kept getting "starter battery critical" warnings.
And now, with this new battery, it's mostly always at "starter battery partly charged."
Are battery issues common with the LCI model?
A good example:
Last edited by ////AMG_C43; Feb 12, 2021 at 08:17 PM.
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FWIW, I've never had to use Xentry when replacing a battery. It's a good idea to close all windows and sunroof to make re-synchronization necessary.
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Last edited by l3m; Feb 13, 2021 at 05:39 PM.
It seems an excessive cost and would like to ask you if you were able to replace it by yourself and reset the ECU? and if you can lead me in the right direction.
thank you in advance
I used an Interstate from Costco and I couldn't be happier! 3 year NON-PRORATED warranty. and only $260.
Took maybe 15 minutes to replace from start to finish.
FWIW, I've never had to use Xentry when replacing a battery. It's a good idea to close all windows and sunroof to make re-synchronization necessary.
I'll NEVER buy an OEM battery for ANY car I own again. I can return this battery to Costco after 35 months and 29 days and they'll hand me a brand new one no questions asked.
Hook up a battery charger while you replace it and you don't have to reprogram anything.
The readings came back as 12.3V, I confirmed low voltage when I went to the local BatteriesPlus store and they tested it at 12.5V and did a load test and it didn't hold up.
The AGM battery is expected to have 12.8V to < 13.5V if I remember what the BatteriesPlus sales associate said.
So knowing I had to replace the battery, I stopped by Costco and bought the Interstate H6/48 AGM battery, which set me back $195 (including a $15 core return fee, which I'll get back when I return the used/flat battery).
It seems smaller than the Mercedes stock battery, so I think the 2018 C43 can actually take a H7/49.
Anyway, after the replacement, I cycled the power windows and the roof and everything seemed normal and then went for a 20 min drive.
To my delight, ECO stop/start works again! (I know you guys don't like the feature, but I like to know that I have the power to turn it on/off at will)
The battery replacement was pretty easy.
You guys are a wealth of knowledge and I appreciate it!
The readings came back as 12.3V, I confirmed low voltage when I went to the local BatteriesPlus store and they tested it at 12.5V and did a load test and it didn't hold up.
The AGM battery is expected to have 12.8V to < 13.5V if I remember what the BatteriesPlus sales associate said.
So knowing I had to replace the battery, I stopped by Costco and bought the Interstate H6/48 AGM battery, which set me back $195 (including a $15 core return fee, which I'll get back when I return the used/flat battery).
It seems smaller than the Mercedes stock battery, so I think the 2018 C43 can actually take a H7/49.
Anyway, after the replacement, I cycled the power windows and the roof and everything seemed normal and then went for a 20 min drive.
To my delight, ECO stop/start works again! (I know you guys don't like the feature, but I like to know that I have the power to turn it on/off at will)
The battery replacement was pretty easy.
You guys are a wealth of knowledge and I appreciate it!








