What does Service A, A1, A2, B, B1, B2, C, D, E, E1, E2, E3, F, G, H, indicate when it appears in your Instrument Cluster. The letter is a reference to the time required to perform the indicated service. A = 1 hour, B = 2 hours, H = 8 hours, if a plus symbol ( + ) also appears this is an indication that an inspection of the Brakes is required while performing the required service.
This can lead to some confusion as most Servicing of Mercedes Benz vehicles is performed either doing a Service A, or Service B. Service A, being a minor service and Service B, being a major service. Servicing is required due to mileage or time, a Service is required yearly.
Service requirements are different from model to model and on the year of manufacture.