The purpose of the fuel injectors is to specifically inject fuel into the combustion chamber depending on the requirement at a given time. The requirement is calculated (non-trivial) in the engine control unit MSS70. The valves are activated individually by the control unit.
To check the fuel injectors, the components are activated individually in cycles. The activation must take place with the S54 engine switched off. A clocking sound is audible. Subsequently, the engine must be started to burn the injected volume of fuel.
Alternatively, the control unit functions under the menu item <component activation> provide the possibility to switch individual fuel injectors off briefly. With the fuel injectors switched off, engine operation is unsettled.