See also:

Fuel quality
Fuels that are marked on the gas pump as containing metal must not be used. Refuel only with unleaded gasoline without metallic additives. Do not refuel with any leaded gasoline or gasoline with ...

For 520i and 528i: Check oil level
The concept The oil level is monitored electronically during driving and shown on the Control Display. If the oil level reaches the minimum level, a check control message is displayed. Displayi ...

Coolant temperature
Should the coolant, and with it the engine, become too hot, a Check Control message is displayed. Check the coolant level. ...