Under certain conditions, wear can occur on individual intermediate levers in the variable valve gear. As the wear only occurs at specific points on the intermediate lever contact surface, it cannot be detected under all engine operating conditions. For that reason, there is a special system test for diagnosing intermediate lever wear which spans the entire range of adjustment.
In order to be able to start the system test, the following conditions must be met: Engine at normal operating temperature, air conditioning off, engine at idling speed, vehicle road speed = 0, accelerator pedal not depressed, engine not choked (Valvetronic not open).
During the system test, the engine is changed from unchoked to choked mode at idling speed. If there is intermediate lever wear, misfiring will occur during the changeover. The misfires are added up for each cylinder. If specific limits are exceeded, worn intermediate levers are diagnosed.