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.

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k