What’s the preferred replacement? I’ve got a code (B21059A) that the battery isn’t up to snuff and also at U0401 code that I am hoping is related.

 

factory battery lasted 9 years in my 2013 gl,now in my 2017 it has a date 2022

 

I bought a battery from the MB dealer for my W166. Dealers in my experience are competitively priced on batteries (and tires) compared with local retail shops. Plus at the dealer you know the part number/model is correct.

 

Some dealers are surprisingly competitive at the parts counter, but maybe not so much in the service bay. If you're a DIY'er, check prices online at the auto and box stores.

 

I ended up going with the offering NAPA had. They were running a 10% off battery sale. The replacement job wasn't too bad, and the CEL went out immediately.

 

Got this cool thingy,tells me battery health,state of charge

 

I have 2 of these -- one is a Foxwell and the other is a Topdon. I haven't used either one enough to opine as to their usefulness, but it is important to attach them directly to the battery terminals and not the engine compartment jumper terminals (if your vehicle is so configured).

 

true,it gives me totally diferent reading when i connect to jump terminal under the hood