w203 Changing battery
 

Do i need to worry about anything when changing the battery on a 2007 C230? Ive read there are no radio codes to worry about but is this job a DIY, no diagnostic tool needed?

I had no problems doing it on my 2004 C240. Bear in mind that the battery is very heavy, and it is in there a ways from where you would be standing, so it takes a certain amount of strength to lift it up and out without dragging it across the fender. Probably easier for a tall person. Once I got the new battery in, I had to re-seat it a couple of times before I got it into position where the hold-down clamp would set into place. You will need a socket wrench with a fairly long extension in order to deal with the bolt for the hold-down clamp. Be careful swinging the ratchet as it will be in close proximity to the positive terminal.

Is it worse than on a 123 300D? I've been tempted to remove the air filter housing when changing batteries just to get some more room to get that heavy bastige in and out

Easier than a W123....there's a little more room, and the stock battery for a W203 (gasser) is smaller than the enormous group 49 (H8) that the diesels have so its not quite as heavy.

Mercedes has a battery replacement service. Just call 1-800-FORMERCedes. Same price as at the MB parts counter and they install, reset any features and recycle the old one. They'll come to your house or work and you then qualify for 18 mos of roadside service. About $175-$200 -- varies by dealer.

Done! Replacing the battery on the w123 is much easier. Battery looks like a group 49 also. Much easier if you get the hood shock out of the way. Its a tight fit. Everything worked as before. Didnt have to adjust the clock or set the garage door opener again - probably an aux battery somewhere.

The C230 2007 models had a command unit. It's nice to not have to remember your code when changing the battery.

Family member owned an '04 and had to have a code. I don't recall though him ever changing the battery since he only had it for two years.

They have an aux battery. Can't remember where it is.

I found this out when my battery drained (as a result of a bad seat controller) and triggered the alarm, and when I pulled the battery terminals off it kept chirping at me.

I don't think the W203 has an aux battery. That's only on models like the W211 e-class with the SBS braking system. It might have provisions in its electronics to retain memory/power for a short time during a battery replacement, but I don't think they have any other physical batteries.