What does service code AO indicate? on 2008 Mercedes-Benz C300 4MATIC

I get a service code of AO on my instrument cluster. I know A means the oil and filter are due for a change, but Mercedes would not tell me what the "O" service code means. Check brake pads and rotors, change brake fluid perhaps????

by in Manteca, CA on February 18, 2011
Get Your Car Fixed at a RepairPal Certified Shop.
We certify shops based on expertise, quality work, and verified customer reviews
1 answer 2 comments
ANSWER by , February 18, 2011
i service mercedes and never seen an o service. could it be a D service you seen?
COMMENT by , February 20, 2011
It may be. The A and O or D are right next to one another on the instrument panel. It states AO or AD Service due in 900 miles. What is a "D" service? Thank you for your reply and assistance.
COMMENT by , April 08, 2011
it states A O