The maintenance indicators are used to remind the operator of needed service. Typically service interval indicators are usually triggered by mileage, and the owner should also factor in the seasons and the type of use the vehicle is subjected to.
The following is a list of what most manufacturers consider severe use. If the vehicle meets any one of these conditions, even if not indicated by the service indicator, maintenance should be performed more frequently. The following is a general list of severe operation conditions.
One category not mentioned in severe operating conditions is vehicles used for competition or high performance driving. It goes without saying that a machine used at its limits should be maintained more frequently, both in the interest of reliability and safety. BMW's are very competent for operation in a high speed closed course environment and will provide many hours of trouble free operation if properly maintained.
The BMW maintenance indicators are unique in that they are not triggered strictly by odometer mileage. The early versions tracked a number of parameters to deduce the type of use the vehicle has been subjected to. Later versions simply monitor the vehicle's fuel economy as an indication of how the vehicle has been operated. The Engine Control Module (ECM) uses the information to determine when the Oil Service and Maintenance Indicator warning lights should be turned on. Therefore the service indicator is activated much sooner for vehicles driven in severe use situations.
The service indicator should be reset using a suitable scan or reset tool. These tools are readily available and designed specifically for the vehicle to avoid damaging any of the components. Some enthusiasts have found methods using home made tools to reset the service indicators, however in doing so there is also risk in doing irreparable damage to other very expensive components, including the Engine Control Module (ECM), also referred to as the Digital Motor Electronic (DME) control module. For the cost savings in performing your own maintenance, these reset tools will pay for themselves over the long run. And, if you are ever willing to part with your BMW, it's a nice token of added value.
When resetting the service indicator, follow the directions for the specific tool as supplied by the tool manufacturer.