B Service
 

I have a 1999 ML 430 88,000 miles. I've only had it for about a week. Should I do the B service?

if the service indicator in your instument cluster says you are due, then yes. if you have more miles to go, then no. if the previous owner was careless and did not perform the services (you'll have a negative sign in front of the mileage til service), then yes, and hope they at least changed the oil.